Historic, Archive Document Do not assume content reflects current scientific knowledge, policies, or practices. ENTERED IN THE COMKTTEH' \***Lio «°"f O' os- PROCEEDINGS OF THE 32ND SOUTHERN PASTURE AND FORAGE CROP IMPROVEMENT CONFERENCE Texas A & M University Agricultural Research and Extension Center at Overton and Longview, Texas May 20-22, 1975 Ds» ,-rn —f c_ 2*. rn 20 1 r-r- co coCT 507 O CD > >. __ “r- o |vs Rc i — CD re .-i -cr o This publication is reproduced from camera-ready copy supplied by the Conference. The views of the participants are their own and do not necessarily reflect the views of the U.S. Department of Agriculture. Trade names are used in this publication solely for the purpose of pro- viding specific information. Mention of a trade name does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture or an endorsement by the Department over other products not mentioned. Agricultural Research Service U.S. DEPARTMENT OF AGRICULTURE July 1976 This publication is available from Homer D. Wells Agricultural Research Service Tifton, Ga. 31794 CONTENTS Page PROCEEDINGS OF THE 32ND SOUTHERN PASTURE AND FORAGE CROP IMPROVEMENT CONFERENCE The Forage Situation, By William E. Barksdale 1 Forages and Beef - Still a Winning Combination, By L. S. Pope 5 The Fertilizer Situation: Present and Projected, By Edwin A. Harre and Gerald G. Williams 9 Foundation Seed Project, By C. S. Garrison and C. M. Rincker 14 Forage Fed Beef Challenges It Presents, By Joseph C. Purcell 23 Symposium II: Panel Discussion of Forage-Fed Beef, By Carl S. Hoveland.. 27 Discussion following panel concerning the production of beef on pasture.. 31 Forage Research in the Southern Region: Objectives, Emphasis and Trends, By A. W. Cooper 35 A Regional Approach to Breeding Forage Crops, By J. E. Halpin 42 Significant Advances in Plant Tissue and Cell Culture, By Earlene A. Rupert 44 Exploration and Collection of Paspalum Species in South America, By Byron L. Burson 52 Producing Seed of Tillman White Clover, By Pryce B. Gibson 56 Advances in Rhizobium Specificity and its Significance to Forage Legume, By Joe C. Burton 57 Inoculation Techniques for Temperate Forage Legumes and Their Affect on Rhizobium Survival, By Richard W. Weaver 68 Digitaria Genotypes Evaluated in Brazil for Nitrogenase Activity, Yield and IVOMD, By Stanley C. Schank 79 l Grass-Bacteria Nitrogen Fixation in Florida - Preliminary Results, By Rex L. Smith, M. H. Gaskins, S. C. Schank, and D. H. Hubbell 87 Growing Calves to Yearlings on Winter Annual Small Grains and Grasses Plus Legumes and Summer Perennial Grasses, By Sidney C. Bell 91 Research in Tennessee Related to Grass Tetany, By John H. Reynolds 93 Programming Models for Forage-Beef Systems, By W. A. Halbrook 95 THE FORAGE SITUATION By William E. Barksdale — ^ The forage situation in the United States today can be described in sever- al terms which are not entirely consistent with one another. One could say that the forage situation in the Southeast and parts of the Eastern United States is currently very critical. A recent 3,500 mile, nine state tour of forage production and livestock enterprises revealed that beef cattle in general are in about as poor a condition as has been witnessed since the 1930' s. This is because the heavy inventories of beef cattle now on farms as a result of low prices have overburdened forage supplies. This presents a challenge for future generations of forage farmers--we must not repeat this sort of experience. Obviously, the conditions will only worsen if we have dry weather this summer. Another way to describe the current forage situation is to say that for- ages are gaining in value. Recent figures from the Statistical Reporting Ser- vice indicate that hay sold for an average of $31.30 a ton in 1972. In 1973 the average price was $41.71 per ton. The 1974 average price was $50.78 per ton. Similar increases have been noted in the per acre grazing fees being charged in various areas. A third way to describe the current forage situation is to say that forages are receiving increased emphasis. A recent agricultural publication surveyed its readers, 907, of whom have some type of pasture and 747, of whom have some sort of hay crop. Seventeen percent of those who have pastures said they were increasing their pasture acreages in 1975 and 24% of those who grow hay said they were increasing thfeir hay production this year. On a more meaningful basis, however, I think it is accurate to say that the current forage situation is one of extreme optimism for the future- -because, in my analysis, forages are on the threshold of a completely new level of value in American agriculture. I feel that this is a fact because of the new pre- miums which the world food economy has placed on the U. S. grain and oilseed supplies . We Americans have been widely exposed to three myths about the increasing value of grain. We have been told that worldwide weather conditions in 1972 caused a temporary shortage of grain, but this is not a valid fact because 1972 was, at that time, the second highest grain production year in the world's history. We also have been told that the increased prices seen in 1972 and 1973 were due to a temporary leap in world grain consumption and that it would not be continued. This, however, is not a fact. World cereal grain production has increased by an average of 27 million metric tons per year since 1960. 1/ Barksdale Agri-Communication, P. 0. Box 17726, Memphis, Tennessee 38117. 1 A third myth that we all have heard is that Russia bought all the grain in 1972 and 1973, and that this caused an unusually high grain price which will not be maintained. This is definitely erroneous. The amount of grain moving to the Soviet Union in 1972 and 1973 from the United States represented only 207o of the increased volume of grain moving from this country. The remaining 807o of increased volume of grain exports went to countries around the world. Three factors which have caused demand for U. S. grain are a growth in world population, increasing affluence around the world, and, simultaneously, increased consumption of poultry and livestock. All of these factors combined to place new world premiums on grains and oilseeds. This, in turn, places new priorities on the role of ruminant animals (primarily cattle and sheep) in converting forages to meat, milk and fiber. In the past, the United States has utilized about 757o of its corn crop in feed for poultry and livestock. If, in fact, world customers are interested in utilizing a greater percentage of our U. S. grain now for human food, we can provide them increased tonnages of grain without sacrificing our standards of nutrition here in the U. S. We can simply utilize more forages and less grain in the production of meat and milk. The United States is in a uniquely advantageous position to make such a transition in its animal agriculture. Of the 2.3 billion acreas of land in the Continental United States, about 1 billion acreas are currently involved in forage production. This land currently is producing at about 227> of its po- tential according to the American Forage and Grassland Council. At present levels the United States produces about 213 million Animal Unit Months from forages. This could be raised relatively easily through currently available technology to about 560 million Animal Unit Months--with an ultimate potential of about 1700 million Animals Unit Months possible. An Animal Unit Month is the nutritional equivalent of about 8 bushels of corn. With corn at $3.00 a bushel, an Animal Unit Month from corn is worth about $24.00. However, an Animal Unit Month can be produced from forages for only $3.00 to $4.00. Obviously, American agriculture can produce a net profit of $20.00 to $21.00 per Animal Unit Month by exporting more corn and making better use of its forage resources. According to Wedin, Hodgson and Jacobson, 737, of the feed units utilized by the American beef cattle population come from forages. Approximately 647, of the feed units utilized by dairy cattle come from forages, and about 897. of those utilized by sheep and goats come from forages. Forages are big business. One way to consider the size of the industry is to appraise the value of forages as feed for beef and dairy cattle. Feed As 7o Total Prd. Cost 7, Feed From Forages FORAGE VALUE RATING 1974 Sales ($ Billion) Value of Forage Contributions Beef 75 75 = .56 X 18 - 10 Dairy 50 65 .33 X 9 = 3 $13 billion Forages have some very special features. First, as you in this audience know so well, legumes in a grass pasture not only increase the nutritional content of the forage but also provide 100 to 200 pounds of nitrogen per acre 2 to fertilize the grass. This, obviously, attains new significance in these days of higher nitrogen fertilizer prices. Conservation and erosion-preventing aspects of forages also have attained new significance in recent years as this country has become more aware of its environmental problems relating to agricultural practices. Also, it is significant to remember that people in many undeveloped nations consider the ruminant animal their only promising link to better supplies of protein. These people have no money to import grain from the U. S. and other major grain exporting countries, and they do not have the soil, climate and other resources to utilize American row crop technology. They do, however, have the climate and abilities to grow abundant supplies of forages and they do know how to manage cattle. They simply need help in improving their efficiency in producing grass and cattle. The South has a very unique advantage in forage production. It has a long growing season, adequate rainfall, a variety of species of forages, adequate acreages of non-row crop land, and relatively mild winters. I have seen, not too many miles from this very location, 30 cows and their calves being carried on a 30 acre pasture year around. Additional emphasis will have to be placed on research if Americans are to make better use of their forage resources in the production of meat, milk and fiber. Approximately 498 scientific man years were devoted to research in forages, pasture and rangeland during 1973 in a total of 1279 projects. This compares to about 498 scientific man years devoted to research in cotton. However, one must consider that forages represent 15 or 20 or more different species, while cotton, of course, is only one. Obviously research needs to be intensified to aid American agriculture in its effort to better utilize for- ages . Consumers will need to be educated about the value of making better use of forages. They will have to be informed that quality is not necessarily going to decline simply because an animal is brought to market weights utiliz- ing more forages and less grain than has been true in the past. Producers will carry an extremely big responsibility in making better use of forages. They will have to group their calving dates more closely to make best use of forages when they are available. For areas growing cool season grasses this will probably mean calving in the early spring. For areas where warm season grasses are grown with overseeded winter grazing, fall calving probably will be preferred. Cattlemen must breed their animals for maximum forage conversion abilities and they must plan to own their calves longer, selling yearling cattle instead of weanling calves. They will also have to make better use of fertilizer and •such practices as rotation grazing and the utilization of crop residues. And, obviously, we all know that producers can do a much better job of harvesting forages for quality content in the future . The American Forage and Grassland Council is striving to aid the entire agricultural complex in making better use of forage resources. AFGC is a clearinghouse of ideas and thoughts in reaching these objectives. Individual memberships cost only $10.00 a year--and the price has been held at that level to encourage you--the forage research and extension specialists, to participate in AFGC. The main burden of financial support comes from the corporate sector, where memberships sell for $150.00 to $500.00, depending on sales volume. State Forage Councils have already been organized in about ten states, including at least three Southern states- -Arkansas , Louisiana and Kentucky. 3 More councils are now being organized-- and I firmly believe that they should exist in states such as Texas, Mississippi, Alabama, Georgia, and others. AFGC conducts an Annual Research-Industry Conference at which scientists, agribusinessmen and producers all have a chance to discuss their observations and findings in the forage field. AFGC also publishes Forage and Grassland Progress, a newsletter which goes to all members, as well as a special Corpor- ate Members Newsletter. The condition of the organization has improved vastly under its first year of having an executive vice president, Warren C. Thompson. AFGC has published a brochure which explains the role of the organization and the value of the forage resources of America and the organization also recently published a leaflet for aiding the organization of additional State Forage Councils. Annually, a membership directory is published, also. AFGC has just initiated a program which will produce six new publication within the next year or less. These are as follows: Managing Pastures to Maintain Legumes Crops for Silage Forage for the Dairy Herd Forage for the Beef Herd Fertilizing Pastures Improved Pastures--Why and How? AFGC has a special Hay Task Force which is investigating several areas of the hay industry including the bases on which hay is priced and the possibili- ties for more effective packaging systems for hay. About 20% of the total U. S. hay crop is sold in one form or another. In 1973 this amounted to 27 million tons of hay which sold for 1.2 billion dollars. AFGC also will soon initiate a special panel of forage farmers which will be surveyed periodically to measure their results, attitudes, and intentions. In conclusion, I think that forages face an entirely new future of utili- zation in the production of meat, milk and fiber for American consumers. Pro- fessional workers and producers who respond to the challenges ahead no doubt will face new opportunities in connection with this trend. We Americans simply must make better use of our resources for feeding humans--and a very critically important part of this total picture is the utilization of forages by ruminant animals . 4 FORAGES AND BEEF - STILL A WINNING COMBINATION By L. S. Pope -l While there has been much furor lately over the wastefulness of heavy grain feeding of beef cattle, particularly in drylot fattening on the Plains, a fact largely overlooked is that it is primarily forage that produces the bulk of American beef. First, there is the maintenance of nearly 45 million beef cows, almost completely on range or pasture. Add to this the millions of acres of improved pastures for yearling cattle, plus eight million acres or so of wheat and small grains grazed during a normal winter, and millions of tons of silage and hay used both for growing cattle and in finishing rations. So, when the critics of the beef industry talk superficially about cutting one hamburger from our diet and thereby increasing tremendously the grain available for human food, they should bring themselves up to date on the true nature of the inputs into a total beef production unit. For example, beef cattle utilize nearly 900 million acres of range and improved pastures in the U. S. each year - nearly 75% of our land total. This has no market outlet, in most cases, other than through the ruminant. And even with emphasis on drylot fattening of cattle, it is estimated that only 407o of the final weight of most finished steers is the result of the feedlot program. Therefore, about two-thirds of final weight is represented by the contribution of grass or harvested forage. Rapid and dramatic changes in the U. S. beef industry over the past 18 months point to some permanent shifts in structure and organization - reaching down to every level of American beef production. So great has been the economic impact of developments during 1974 that the U. S. beef business may never be quite the same again. What are some of these changes and what do they mean, particularly to cow- calf producers and feedlot operators? Let's take a close look at what is happening to agriculture's largest money-earner the production, processing and retailing of U. S. beef. Unlike the '30's, the price collapse of 1973-74 hit a highly capitalized business, greatly dependent on other segments of agriculture and industry. We were caught with too many heavyweight, over finished cattle, together with bulging cow herds. Retailers held their margins high while live cattle prices collapsed. The fed beef market has remained "soft" for nearly 18 months. Continued financial loss by investors caused outside sources of capital to dry up. Since outside capital was one of the major factors bolstering feeder cattle demand, the result of withdrawal had a domino effect on feeder cattle prices . ]_/ Associate Dean of Agriculture, Texas A & M University, College Station Texas 77843. 5 Coupled with this, the year 1974 marked a dramatic shift in the cost of feed grain. Many feedlots on the Plains were established on the concept of cheap grain. Grain alone makes up nearly 807, of the feed costs for fattening cattle. Thus, a sharp increase in grain prices was sufficient to drive costs right through the ceiling. With a shorter- than-expected grain crop in 1974, many cattle feeders were reluctant to try it again. The results was the worst loss in feeder cattle returns since 1954. Obviously, grain supplies cannot be replenished before another crop is produced in 1975. Even then, some authorities believe we will have to see back-to-back record grain crops before the cost of grain comes down much since the export demand for corn and grain sorghum will remain strong. What is likely to be the result of all this? Many experts in the beef business say we are witnessing the beginning of a vast change within our indus- try. They believe that the days of long-fed cattle, fattened on cheap grain for 180 days or more in drylot, are gone for this decade, perhaps forever. In the future, they believe, we will see more yearlings and cattle weighing 700 pounds or so, fed less than 120 days on heavy grain rations. The recent pro- posal to change the grading standards for beef carcasses with less emphasis on marbling, will certainly be a step in this direction. Many predict that with world-wide grain shortages, we will see, at least locally, a return to "forage finished" beef. Experiments at several southern states, notably Louisiana, Georgia, and South Carolina, have shown that it is indeed feasible to fatten steers to an acceptable degree of finish on forage alone. Farmers in the Midwest have long understood the value of excellent corn silage, properly supplemented, as a ration for finishing steers to the Good- to-Choice grades. However, before "forage finished" beef can be produced in volume, some sobering obstacles must be considered . For example, in most regions the production of excellent forage is a seasonal proposition. To be an important source of beef, it would have to be produced over a longer period than now seems likely. Further, most large packing operations have followed the feedlots west. Thus, local packers seem to be the best outlet for this type of beef and the supply will be seasonal. What will be the consumer's reaction to a difference in beef quality, to the possibility of a slight yellow cast to the fat of grass- finished beef? Also, grass- finished cattle will yield less than those finished on heavy grain rations, thus killing costs per hundredweight of product will be higher. These obstacles must be considered before a serious inroad can be expected from "forage finished" beef as a part of our total beef system. It seems logical that we will see a return to the fundamentals of beef pro- duction, to greater emphasis on weaning weights, greater use of winter and spring pastures in producing cheaper gains. Perhaps this is as it should be. Large commerical feedlots had an unlimited demand for nearly every feeder calf we could produce during the 1960's. By 1973, nearly 75% of our total calf crop passed through feedlots, large and small, before slaughter. In a real sense, feedlots dictated the direction of the entire beef industry. Heavy weaning weights from fertile, highly productive crossbred cows will again resume the ir rightful importance. Cattlemen may look to combination cow- calf and yearling programs. Production of lightweight calves will be discour- aged. These trends can be important for the beef industry. We should never have been diverted from this goal in the 1960 's by the heavy demand for feeder cattle of any weight, shape or age. Improved pastures for Stocker calves and yearlings will also assume added 6 importance. The high cost of grain will encourage the feeder to buy weight in the form of heavier feeders, rather than feeding it on. However, feedlots will still occupy a crucial position, if for no other reason than that they provide an assembly point for the finished cattle which must supply most of the 60 million pounds of beef consumed each day by hungry Americans . But it will be a cattle feeding industry that will be only one part of the total beef system. No longer will large feedlots dominate the beef industry, rather they will provide the short, heavy grain- feeding phase which many believe is necessary to produce the "eating quality" of beef which Americans prefer . Abundant forage, therefore, will become the key to profits in the next phase of the U. S. beef industry. Can we produce it economically, manage it efficiently and utilize it to greater advantage in the years ahead? That is the question that must be answered as we progress through the last half of the 1970's. For one thing, it takes lots of forage just to maintain our cow herds and put gain on growing cattle. Estimates are that it takes about 125 million pounds daily just to keep our operations going in Texas. With this massive in- take of forage, whether from native range or improved pastures, beef produc- tion has been relatively efficient as compared to other species. It has been calculated that due to the large percent of the total ration of the cow and growing calf derived from forage, it requires only 2.9 pounds of concentrates per pound of total gain on the finished steer at 1,100 pounds. This is only slightly above that required by the broiler, and even better than the pig. However, events of the past two years have shown that forage is no longer a cheap feed, whether produced on native range (due to high costs of land) or on improved pastures (due to high cost of fertilizers). Costs per acre of establishing small grain pastures were estimated at $90/acre in East Texas last fall. Nitrogen shortages and high prices have stimulated interest in legumes - an almost forgotten subject two years ago! Likely, the costs of fertilizer will remain high and shortages will occur in phosphate fertilizers from time to time. Already, producers have begun to cut back on fertilizer use, as indicated by recent tonnage figures. After all, when calves were 60q per pound, it was easy to think of pasture fertilization. This year, many good pasture management and fertilization programs will suffer from the high cost of doing business. While caught between the "rock and a hard place", the producer should con- sider the costs of not fully utilizing all his resources to the maximum in mod- ern beef production. When forages are not fertilized so as to yield maximum tonnage, other costs of production increase, percentagewise. Interest on in- vestment, taxes, labor, and operating costs still continue whether or not cows wean a larger and heavier calf crop or yearling cattle gain 1.0 versus 1.5 pounds per day. When all costs are considered, cattlemen are "locked in" to a rather rigid set of economics and maximum production of forage remains the key to profits. Lastly, let's not be too pessimistic about the future of beef. In 1975, lucky Americans will consume the greatest tonnage of beef ever produced in U. S. history . And they will pay little more in terms of percent of disposable income for beef in 1975. Few other items in our inflated economy fall in this class. But Southern beef producers in 1975 and beyond will need a better "systems approach" to beef production. Starting with "custom built" cattle, genetically engineered to be highly fertile, grow rapidly and produce a superior 7 carcass, the beef man will use every management tool and technique to increase output per cow unit. Forage, obviously, will be the key to success. There's an old adage in the beef business: "Fit the cattle to the feed supply." This implies "fine tuning" of cattle and feed resources to obtain maximum yield at minimum cost. It will require investments in cattle and feed to do this. Shorting beef cattle on an ample supply of forage may be the most costly mistake in the beef business today, since costs of other items of pro- duction continue to mount as cattle stand still in performance. Nearly all experts agree that the long-range outlook for beef is good, despite current economic problems. We can do the job of producing lean, thrifty beef for U. S. consumers and still return a decent profit only by the "forage route" since the long-range picture calls for rather high grain prices through the remainder of the 1970' s. Southern cattlemen need your help to assure a continued output of millions of pounds of carcass beef daily - and you need a profitable cattle industry to make your efforts worthwhile. To- gether we form a winning combination. Let's hope the lucky U. S. consumer appreciates our efforts. 8 THE FERILIZER SITUATION: PRESENT AND PROJECTED By Edwin A. Harre and Gerald G. Williams — ^ The U. S. fertilizer industry has made a full cycle. In the last two years it has unmired itself from five years of overcapacity, overproduction, minimal growth in demand, excessive inventory levels, and low profits where any existed at all. During this time, new plant construction was almost at a standstill because of the poor economic condition of the industry. When the demand for fertilizer materials did pick up again in 1974, the lack of suffi- cient capacity led to shortages in the supply of all three primary plant nutrients and prices increased rapidly. However, now the exaggerated profit picture of the last few months is stimulating new investment in the industry, and supply is once again increasing faster than demand. Fertilizer Prices The recent rise in retail fertilizer prices is shown in Figure 1. The price freeze imposed in 1970 came at the lowest level that fertilizer prices had reached in many years. With little prospect for adequate returns on invest- ment, plant construction stopped, and producers searched for new markets. In October 1973 in an attempt to increase domestic supply levels that had become abnormal- ly low because of the attractive export market, price controls were removed. Fertilizer prices doubled almost overnight. They have continued moving upward since then--out of proportion with agricultural commodity prices which began to stabilize or decline during 1974. With relatively unfavorable ratios of farm output to fertilizer price, the farmer has taken a second look at his soil fertility needs. Instead of demanding more plant food he is calculating the lowest level he can use without suffering a significant yield reduction. Today the bubble ha s bur st , fertilizer materials are stacked in warehouses all over the country, and fertilizer prices are backing off from recent high levels. Fertilizer Inventories The wet spring weather and the fact that many farmers had purchased and stored fertilizers prior to the spiraling price change of the last few months left producers--who had pulled out all of the stops to increase production-- shipping to storage rather than to the retailer or farmer. Inventory levels that had been virtually depleted in 1973, as indicated in figure 2, were on the climb once again, and it should be remembered that this measurement of stocks l / Fertilizer Distribution Analyst, Test and Demonstration Branch; Director, Division of Agricultural Development; Tennessee Valley Authority, Muscle Shoals, Alabama 35660. 9 on hand is taken at the producer level which only begins to accumulate after retail and regional storage areas have been filled. As we end the 1975 fertilizer season, it is apparent that demand did not reach expectations and that the normal spring drawdown in inventory will not deplete stock levels to their normal lows. The supply position for each plant nutrient is not the same. Each has experienced different market prospects and restrictions . A brief discussion of the future supply-demand situation through 1980 for the U. S. nitrogen and phosphate industries and the North American potash producers follows. Nitrogen Nitrogen use has increased more rapidly than either phosphate or potash, averaging better than a 7.8 percent annual increase during the last decade. Farmers are now applying twice as much N in relation to P2O5 or K^O. By 1980 TVA has forecasted a continuation in this growth pattern; however, at the reduced annual rate of near six percent. If this rate of gain is achieved, it is expected that the U. S. farmer will be applying 12.5 million short tons of nitrogen to his soils. It has recently been thought that the U. S. would be unable to supply the U. S. farmer with this amount of material from domestic production. A return to our net import position was expected to last indefinitely as critical short- ages of natural gas have put a damper on any expansion plans for the industry. But the attractiveness of the market and the risks involved in the investment in plants and equipment in foreign countries has brought about a number of new ammonia plant announcement s for construction within the boundaries of the U. S. As indicated in Figure 3, the majority of these new plants is scheduled to be- gin operation in 1976 and 1977. At this time, the industry will once again be in a position to produce enough nitrogen to satisfy the domestic market and have an exportable surplus. Total nitrogen production capacity in the U.S. is just over 15 million tons N and is projected to reach over 21 million tons N by 1978. At a 90 percent operating rate and considering processing losses and the nonfertilizer market demands, this level of capacity will result in a potential nitrogen supply for fertilizer of over 13.5 million tons N by 1980. While comfortably above the projected demand of 12.5 million tons for the same year, it does not account for any possible closing of plants during the interim when a surplus exceeding 13 percent of the projected demand is expected. Considering the age of many smaller ammonia plants in the nation plus the marginal economic posi- tion of some of the smaller scale units recently reconditioned and brought back into production, it is reasonable to assume that more than a million tons of ammonia capacity will be phased out in the next few years. If this is the case, by 1980 the nitrogen industry could be facing the need for additional capacity as the supply cycle continues to move through periods of deficits or surplus . One factor in the nitrogen market that cannot be overlooked is the recent announced expansion of ammonia plants in the Canadian province of Alberta. Natural gas reserves are abundant in that region and offer an alternative supply source for the U. S. market. Two plants of 400,000 tons each of ammonia are under construction with six others of similar size approved by the Alberta Energy Board. These units still await approval by the Provincial government. If they come into production as currently scheduled, however, North America will have ample nitrogen supplies and will need to establish itself as a major 10 world nitrogen supplier in order to achieve a domestic supply-demand balance within reasonable economical operating rates for these new plants. Phosphates It is difficult to project future growth in the use of phosphate fertili- zers. Over the last 30 years this market has increased at an annual rate close to 4.5 percent. In recent years growth has slowed, but the market has contin- ued to expand. However, present farmer uncertainty, poor weather conditions, and adequate P9O5 levels in many soils suggest that use in 1975 will be signi- ficantly below previous levels . The question of the future use of phosphate materials under more favorable price relationships with agricultural commodi- ties in view of soil reserves remains to be answered. The argument may be academic. Regardless of the optimism or pessimism applied to the demand forecast, it is apparent that future supply levels will be more than adequate to satisfy demand and keep exports well above current levels. As indicated in Figure 4, the large scale expansion program initiated in 1972 because of anticipated favorable export market conditions is now coming into production. Four new phosphoric acid units began operation this spring, rais- ing the nation's phosphoric acid capacity by almost two million tons of P2O5. Addi- tional units tentatively scheduled for the remainder of the decade would bring total capacity to near 10 million tons by 1980, thus the wide divergence between supply and the most optimistic of demand estimates as presented in figure 4. Phosphate rock producers have undergone the same market problems faced by the nitrogen and phosphate industry since the middle of the 1960's. Little expansion has taken place in production, sales have exceeded production since 1968, and a steady inventory reduction has taken place. Recent price changes also brought about large scale expansion in rock mining in the U.S. and there now is not expected to be any limitations on phosphate fertilizer production from a short supply of phosphate rock. Potash During the 1974 fertilizer season, potash producers enjoyed one of their best years. Reported deliveries were up 20 percent over the previous years and consumption increased faster than either nitrogen or phosphates. Canadian producers were allowed to operate without quotas for the first time since 1970; however, significant production increases were not immediately forthcoming since additional investment was needed to bring long idle facilities up to full production levels. As seen in Figure 5, North American potash producers will need to operate their plants at more than 70 percent of the total capacity presently available. A 10 percent increase in the overall production level should assure adequate supply levels for the North American domestic market and allow a continuing expansion of offshore trade of up to about two million tons by 1980. Canada now supplies about 75 percent of the U. S. potash market with pro- duction from Carlsbad, New Mexico, making up the remainder. Recently there have been some announced expansions at the potash mines in New Mexico. How- ever, with the exception of the reopening of one plant, little in the way of additional production is expected. In the future the supply of potash for the U. S. market should remain adequate as long as there are no restrictions imposed on producers that would discourage any necessary investments in plant and equipment . 11 Summary Once again, the laws of supply and demand have brought the fertilizer market through another cycle. After the short supply levels of the 1973 and 1974 fertilizer years, increased price levels have stimulated investment in the industry and new capacity is becoming available to satisfy the market demands. Phosphate and potash supplies should be ample for the remainder of the decade, while nitrogen supply will follow by 1977. The future supply-demand balances and the prosperity of both the farmer and the fertilizer industry will depend on maintaining an equitable price relationship between agricultural commodi- ties and fertilizers. Fertilizer remains a vital input in the nation's agriculture, and its use will continue to expand as long as the farmer con- tinues to receive a favorable benefit-cost ratio with its use. Generally speaking, the problems of the fertilizer industry in the lastdecade stem not from lack of demand but from overreaction on the supply side of the equation. 1965 1970 1975 Figure 1 U.s. FERTILIZER PRODUCER'S INVENTORY LEVELS 12 MILLION SHORT TONS K?0 MILLION SHORT TONS US. NITROGEN FERTILIZER SUPPLY U S. PHOSPHATE FERTILIZER SUPPLY POTASH FERTILIZER SUPPLY Figure 5 13 FOUNDATION SEED PROJECT By C. S. Garrison and C. M. Rincker, ARS BACKGROUND The Foundation Seed Project was approved in 1948 and has operated contin- uously to date. The purpose of the Project is to "build up quickly and to maintain foundation seed of superior grass and legume varieties". Operational phases are concerned only with producing, assembling, distributing and limited stockpiling of foundation seed. Technical, operational and financial support for the project is provided jointly by the Agricultural Research Service and the Commodity Credit Corporation. A Memorandum of Understanding between ARS and the Agricultural Stabilization and Conservation Service, representing CCC, was signed in May 1949. The most recent revision of the M/U was approved on October 5, 1970. The Project continues to play an important role in the rapid multiplication of many improved forage varieties used extensively in the humid regions of the country. Without this program some varieties would not be making the contribu- tion to livestock feed production as is currently the case; others would have been available to farmers only in limited supply. In the mid 1940's, superior forage varieties were grown on less than two percent of the acreage. A study by Administrators in the U. S. Department of Agriculture and the State agricultural experiment stations showed the major factors responsible for this situation were; 1) The failure to develop seed production programs for many small seeded grass and legume varieties in favor- able environments in the western States; this is in contrast to the local pro- duction of cereals and oilseed crops. 2) No organized program for the pro- duction and maintenance of inventories of foundation seed of the superior f orage var ie t ie s . 3) Inadequate educational programs. These three factors have the same importance today as they did 30 years ago although some States have expanded their foundation forage seed activities. Each has a significant bearing on the success of varietal releases from public breeding projects. Inadequate educational programs emphasizing improved varie- ties is still a major limitation. The Foundation Seed Program has built up and maintained foundation seed of forage crop varieties used extensively in the Central, Eastern and Southern States. To facilitate the maximum increase of new grass and legume varieties, the Foundation Seed Program is authorized to assist breeders in maintaining breeder seed and, as may be necessary, to accumulate small supplies of register- ed seed. During the 25 years of operating this program, CCC has not sustained any long-term financial losses. In fact, there has been a small net gain of $300,000 to $400,000 during the period. ARS participation is covered by funds appropriated annually. The operational phases of the program, namely, production, processing, 14 storage, and distribution of foundation seed is cooperative with State agricul- tural experiment stations, State seed certifying agencies, State foundation seed organizations, and seed firms. Each cooperating agricultural experiment station assigns a State foundation seed representative to assist with Project operations in that State. The production and distribution of adequate and recurring supplies of foundation seed is the final stage in the breeding and release of superior varieties. This type of support program is required if the investment in forage breeding is to pay dividends by increasing feed production efficiency. Frequently, new varieties are not multiplied in the quantity needed to meet demand because of inadequate foundation seed. Such varieties as Cumberland and Midland red clover; Atlantic and Buffalo alfalfa; Tift sudangrass; and Climax lespedza failed to meet their full potential because of "too little and too late" effort into the production of foundation seed. On the other hand, Vernal alfalfa was taken into the Foundation Seed Pro- ject at the time of its release in 1953. Eighteen months later there was over 1.8 million pounds of certified seed. In comparison, only 1.1 million pounds of certified Ranger and 14,568 pounds of certified Atlantic alfalfa seed were produced six and eight years following release. The maintenance of foundation seed supplies has made Vernal the most widely used alfalfa variety in the U.S. today. To date more than 280 million pounds of certified Vernal have been produced. This quantity is second only to the record for Ranger which is nearly one billion pounds. Certified seed of Cumberland red clover never was available in adequate supply because stock seed was continually siphoned off and used for forage plantings in the Eastern States. Had there been a program to maintain recurring supplies of foundation seed, this variety would have been used extensively for hay and pasture. Midland red clover adapted to the North Central States fell by the wayside for the same reason. A committee of the International Crop Im- provement Association (AOSCA) tried to coordinate supplies of foundation seed. However, because of limited financial resources, it could not build up and maintain reserves of foundation seed. Another example of the importance of an adequately financed foundation seed program is the record with Gahi 1 pearl millet. This variety was develop- ed at the Georgia Coastal Plains Experiment Station and released for use in the Southeastern States. Foundation seed supplies have been maintained by the Project. In 1963, there was extensive propaganda by the seed trade to encour- age farmers to plant Sudan- sorghum hybrid seed on the Coastal Plain soils in the southeast. This caused a sharp reduction in demand for foundation Gahi 1; zero in 1965. However, the Foundation Seed Project retained its inventories. This resulted in foundation seed being readily available three years later when the demand for planting stock seed was regenerated following poor performance of the Sudan- sorghum hybrids on the light soils. In the late 1960's certified Gahi 1 seed prices dropped severely so that it was not profitable for many growers to produce seed; therefore, there was a reduction in the demand for foundation seed. However, the Project carried over reserves and in 1973 was able to meet the largest demand for foundation Gahi 1 seed. Thus, the Project maintains foundation seed supplies for current distribution and carry-over in- ventories to assure the availability of planting stocks over the long-term. Otherwise, varieties such as Gahi 1 would "die" and be lost to agriculture. Many of the seed firms with their own breeding programs are interested primarily in the production, distribution, and promotion of their own propriet- ary varieties. They have not shown the same interest in handling seed of 15 publicly bred varieties unless they were granted exclusive rights to these varieties. For example, the initial foundation seed of Apalachee alfalfa from the North Carolina Agricultural Experiment Station was released to two seed firms for multiplication and distribution in the area of usage. Four years later there was no reported production of certified seed from these releases. The new Arc alfalfa was released in 1974, 50 percent of the 417 pounds of reclassified breeder seed was distributed through State foundation seed pro- grams, the remainder through two seed firms. The former was planted and most of the acreage produced a seed crop in the seeding year. The foundation seed distributed to the seed firms was not planted until late last fall. According to reports, the firms were too involved with proprietary varieties to arrange for the multiplication of the ARC stock. Approximately 22,000 pounds of cer- tified Arc seed will be distributed in the mid-Atlantic States in 1975 for for- age production. Varieties developed by the Agricultural Research Service in cooperation with the State agricultural experiment stations are not likely to be released on an exclusive basis in the near future because of recent court ruling. Since the large seed firms have proprietary varieties which give them exclusive marketing rights, they are not interested in maintaining the foundation seed reserves of non-exclusive public varieties which must be distributed equitable to all qualified growers who request seed. However, a large number of smaller firms use the public-released varieties as the backbone of their seed business. Current Operations The Foundation Seed Project like other activities has suffered from in- creased prices, costs and inflation. The salvation to date has been the seed in inventory produced prior to 1973 when prices paid growers were 407, to 907o lower than those in 1973 and 1974. Because of the high sale prices and the FIFO method of managing inventories CCC has made limited unplanned monetary gains. These gains may be needed should there be a major break in grass and legume prices in the future. Recent sale prices established for Foundation seed were higher than the purchase price would justify. However, it was necessary to raise the sale price for foundation seed to protect inventories. For example, a seed firm inquired about the purchase of 50,000 pounds of foundation Vernal at the esta- blished foundation seed price of 90q per pound. At the time, certified seed growers were being paid $1.20 to $1.35 per pound for their certified seed. Thus, the project was forced to escalate the sale prices to avoid depletion of its inventories-- the seed to be used for forage planting. Foundation seed production, distribution and inventory. In Table 1, we have summarized data on the distribution of foundation seed by variety in 1973 and 1974; the estimated production in 1974 and the current carry-over inventory on January 1 , 1975. The latter does not include the 1974 production. We need to build up the supply of Ramsey alfalfa. And of course, do better with Agate with which we had one of our occasional failures this past year; the field did not meet certification requirements. The details are given as footnote 4 in Table 1. The supplies of the other varieties are adequate particularly in view of the reduced grower interest in producing certified forage seed. Wheat, sugar beet, potatoes, some vegetable seed crops, etc., are too competitive and can be grown with less risk. Tables 2 and 3 include the annual production and distribut ion of foundation Vernal and Gahi 1 seed. Dr. Brink requested the Vernal information and we used the Gahi 1 data for another purpose. We have similar tables for the other 16 varieties if they are of interest. At the time we prepared the report for Dr. Brink, we were surprised by the quantity of foundation Vernal that has been produced and distributed since its release in 1954. The production of founda- tion seed has amounted to 1,826,398 pounds; distribution 1,592,290 pounds and the total production of certified seed at approximately 280,000,000 pounds according to AOSCA reports. The current CCC inventory of foundation seed as of January 31, 1975 amounts to 234,108 pounds. It is stored in three ware- houses (Caldwell, Idaho; Madras, Oregon; Wapato, Washington) to protect against losses from fire and other calamitous events. TABLE 1 . - -Foundation Seed Production, Distribution and Inventories Foundation Seed Project - January 1975 Dis tr 1973 lbs . ibution 1974 lbs . Production 1974 lbs . Carry-over Inventory Jan. 1, 19752 7 lbs . Alfalfa Agate 1,677 4,218 2/ Apalachee -- 1,394 Arc -- 427 14,5002/ Ranger 4,890 6,428 1,2003/ Ramsey -- 1,9003/ -- Team 930 9,240 -- 4,950 Vernal 84,030 25,680 93,009 141,099 Birdsfoot trefoil Empire Red clover Ar 1 ington 38,0002/ Kenland 15,742 4,098 20,0003/ 10,830 Kenstar 37,0003/ Lakeland 14,100 10,740 31,0002/ 93,623 Pennscott 17,640 9,270 -- 14,190 White clover Til lman2 ^ 465 1,068 (Regis- tered seed) Crownvetch Chemung 55 750 -- 900 Orchardgrass Poto mac 5,910 990 11,617 15,449 Timothy Verdant 1,020 2,010 -- 3,570 Pearl millet Gahi 1 Line 13 37,767 14 , 259— 7 15,692 0 (Blend of 0 lines 13- 18-23-26) 17 TABLE 1 . --Continued Distribution Production Carry-over Inventory 1973 1974 1974 Jan. 1, 19751/ lbs. lbs. lbs. lbs. Line 18 2,076 19,190 Line 23 9,646 672 Line 26 6,376 12,750 Starr 4,500 1,619 15,286 — _1/ Inventory does not include the 1974 estimated production of foundation seed . 2/ A twenty six acre Agate field was established with breeder seed for the production of foundation seed. It failed to meet isolation requirements for certification. After the field was planted a neighbor farmer seeded an alfalfa hay field too close. 3/ Estimate of seed crops in process of being cleaned and certified. Will be added to inventory as soon as available for purchase by CCC . Founda- tion Vernal was purchased in mid-January. 4/ Foundation is distributed by the New York Seed Improvement Co-operative, Inc., Ithaca, New York. 5/ Tillman white clover is a "difficult" variety to handle. It's average yield has been lower than Ladino and other similar varieties. White clover seed production, at best, is not popular with growers except in a few isolated areas. With Tillman's low yields and economic competition from other crops, this variety doesn't have a bright future. We were successful in 1974 in building up the breeder seed supply of the three single crosses from vegetatively propagated material representing the six parental clones. 6/ Distribution of foundation Gahi limited in 1974 due to shortage of line 13 seed. A small crop was harvested in 1973 as a result of an irrigation pump failure. The unexpected large demand for foundation seed in '73 reduced our carry-over inventory of line 13 below the safe limits--a minimum of one years seed stock requirement. We harvested a poor crop of line 18 in '74 again because of a pump failure. However, there is and estimated two-year supply on hand. 18 TABLE 2. --Vernal Alfalfa Seed Production QJ OJ bO d 03 *r— I 01 x CM| r—4 TO S3 0) Cl bO 0) 03 > G o o Pl u 03 03 14-1 OJ i— 4 4-J 03 C 14-1 03 I— I 1— I < cg 14-4 QJ O bC 03 r~° o; g o < LOOOOOOCxJO ^DOOOr^-r^r' I OCOOiO^DiDiOvD HHHMMMtMM oomiDOc^ rx rx rx rx rx rx rx rx rx r> rx rx > *r4 G >x cti Q 33 CN CO x£> O i—4 LO r—4 vO CO 00 LO N- LO CN 00 LO CN tO M-4 C 1 1 X 5-i O i—4 i—4 ON o o CO vO CN co vD CN 00 LO co 00 CN CN •i—l T3 G d •G CU 03 Pl 1—1 1—4 r—4 i—4 i—4 r—4 LO T3 4G S3 G "d 03 rx QJ G CO > >x cu 0) i—4 4—1 G £ "d G Pt4 co X3 O G S3 o O W) T3 O •rH 4-J rx •r4 G •r4 G c CO Q3 G T3 4-1 G G cu s *4-4 G S3l > • i—4 ►]c -]c -jc T3 'TO C 4-J 03 O'-' CN CNI CN vD o LO CO CO O o vD) CN i—4 CO O O O O CN 03 T3 G c G •H CU 03 LO 00 a> N- LO CN CN 00 LO vt CN CO O 00 t—4 vD o J3 03 G d J33 •r-4 •r-4 CN LO O 00 CN CN CN CN 00 LO CN CN CN CN LO O r—4 O CN 4-J > G o 4-J G 5-4 4-1 CO r. rx rx rx r> rx rx rx rx rx rx rx rx rx r> rx rx O X LM > d •p-l X) co 00 i—4 LO vO o T— 1 CO o p^ P^ o co CO r—4 CO o CN LO vO 00 14-1 G G G G > 4-J t— 1 r- "4 CN LO x o 14-4 X S3l TD c 03 - rx rx ** rx rx rx rv rx rx rx *rx r> rx rx •■X rx r« rx rx rx w CO r*H G o G o U i—4 vO CN O CN CN CO r—4 vD CN CN 00 CO 00 r—4 o vD vD LO o •r4 CL >. 4-1 G G J3 •r—4 i— L r—4 r—4 r—4 i—4 i—4 r—4 r—4 1—4 i—4 i—4 CN CN r—4 r—4 i—4 00 w CL 5-4 S3L u X 4-J CN ctf C/3 3 O G u •H cj JO 03 Cb u G 3 G i—4 d G C X G bO Xi X cu G (U G G G 3 O JO CO G > G G CL U 4-J G d W 3 O Oh C G •r4 4-J G Ul 4-1 o c -G >x X o X •rL 3 3 •H *X rx 1 1 1 rx rx 1 1 rx rx u i—4 r4 G G X 4-J C i— 4 CO i—4 r—4 CO vD CT3 CL *l~| X G 33 G 3 i—4 1—4 CO LO CN> o 00 vD LO o CN 00 CN CN B •H G . S3 o O r— 4 i — 1 CN i—4 r—4 CN i—4 CN 00 ' •r4 4-J G G i—4 4-J G CL U* rx 4-J i—l JC r—4 3 G G i—4 W D H G d O H DC r—4 w s u ro vD vO VsO VxD vD VxD vD VxD \D P"x O- P^x 4-J 0) ON ON CN CN CN CN ax CN CN CN CN CN CN CN CN CN CN CN CN CN CN o >< r—4 r— 4 i—4 i—l i—4 r—4 1 r— L i—4 i—4 i—4 r—4 i—4 i—l i—4 i—4 i—4 r—4 1—4 i—4 t—4 r—4 i—l H i—4 i — 1 X r^- i—4 i—4 CN 33 •r-4 o i—4 G 4L X 3 X) •r-i O X d d 4-J G d 4-J s d CU o •H r- L G d rO > CN B d G i — i r—4 G co •r-4 X rx d d G CN JJ > G vD d CN 4-J G i—l o d 3 CO (U x X) 4-J G rx G X d d G LO rx G d X X r—4 cu G T3 o d £ a G G Cl d G G G CU <4-4 G d G G O rC Q X G S3. CL 4J CO CO G d o G) G X 4J S3 r—4 LO H CO O G X CN ■G" rO •H •r-4 G i—4 xD r—4 CO >x 03 03 G 0) CxJ Cxi 19 TABLE 3 -Product ion and Distribution of Foundation Gahi 1 Year Production Lbs . Distribut ion Lbs . Shrinkage Lbs . Inventory Lbs . 1958 27,479 27,479 1959 111,290 11,040 -- 127,729 1960 6,600 17,884 -- 97,974* 1961 0 20,858 1,095 76,021 1962 8,462 28,100 1,706 54,677 1963 98,003 30,664 1,651 120,365 1964 21,840 13,954 1,595 126,656 1965 0 0 1966 0 16,250 -- 110,406 1967 9,027 30,131 930 88,372 1968 0 35,658 514 52,200 1969 69,970 26,700 650 94,820 1970 0 9,150 85,670 1971 0 18,300 -- 67,370 1972 20,350 19,342 258 68,120 1973 40,501 37,767 128 70,726 1974 33,790 14,259 44 , 540** 18,471 lbs. taken out of inventory because of genetic impurity. 11,927 lbs. removed from inventory due to poor viability. The distribution of foundation Gahi 1 seed now amount to approximately one-third of a million pounds; production over 440,000 pounds. In 1974, even though there was an inventory of 70,726 pounds of the inbred lines, we were able to make available only 14,259 pounds of foundation seed because of a shortage of line 13. An irrigation well failure reduced the production to a very small quantity thus this limited the amount of foundation Gahi 1 seed that could be composited for distribution in the spring of 1974. As the production record in Table 1 indicates, we have a good supply on hand of all four lines and will be able to meet total demand. Experience has shown inventories should be maintained at a 2-year supply; never should reserves be permitted to drop below a 1-year planting requirement. When the inventories get below the safe operating level then, by chance of course, we seem to encounter low yields or crop failures. At least when you have adequate reserves the foundation seed crop failures cause minimal concern. Foundation seed production contract. We have requested CCC to review the section in the production contract detailing the price that will be paid for foundation seed. To date, it has provided for a fixed price schedule based on the average yield for the area at a standard price and any seed above this quantity at an excess seed price. This revision is necessary to provide more flexibility in pricing seed in relation to the fluctuating certified seed mark- ets and returns from competitive crops. Because the contract was not amended in time for use in 1974, all the foundation seed except pearl millet was pro- duced under a verbal agreement with the growers. The understanding was that CCC would purchase their foundation seed after the crop was harvested based on the average certified seed price for the crop in the area plus a reasonable premium for foundation seed. The production contract used in 1975 will incor- porate a flexible pricing structure. For example, Vernal is by far the variety produced in the largest volume. It is logical, therefore, to tie the contract 20 price to the certified Vernal seed price on a given date plus a premium for foundation seed. One recent problem has been that certified Vernal to the grow- er is lOp to 25c per pound below the contract for proprietary varieties. This situation may well have resulted from the exceedingly high certified alfalfa seed prices paid growers during the 1973-74 marketing season. This influenced pricing in the 1974 contracts. We believe 35c per pound is an adequate premium above certified seed for foundation seed. Our 1974 alfalfa prices were a little over this f igure--about 45c; Arlington and Lakeland red clover a little under it--about 25c to 30c and Kenland and Kenstar just about on the mark. We had a verbal agreement with the growers that we would purchase their 1974 seed based on prices of certified seed in early December. We prefer the contract! I'm not a good negot iator- - to sympathetic to the "tails of woe" from the growers. They almost had me crying too. There was some justification; alfalfa yields at 250 to 350 pounds per acre and red clover at 350 pounds. On a few farms the same land would have produced wheat yields of 80 to 100 bushels to the acre; at $5 per bushel. Prices for 1974 foundation seed crop. CCC is paying $1.40 per pound for foundation alfalfa seed produced in 1974; except Apalachee which is $1.85; $1.35 for foundation Lakeland and Arlington red clover and $1.50 per pound for Kenland and Kenstar; 50c for Gahi 1 pearl millet and 45c for Starr and 75c for Potomac orchardgrass . The difference in prices for the red clovers relates to yield potential of Lakeland and Kenland over years in the Columbia Basin. However, it isn't possible to adjust for the seed grower factor. Two seed grow- ers have produced most of the Lakeland--probably the two best growers who have produced red clover seed for the Project. They have high average yields--the best was 1600 pounds per acre on 28 acres. If you have suggestions for the best procedure for pricing foundation seed in the production contract, please give us your ideas. We would welcome them. Foundation seed production in 1975. In the coming year we will replenish our supplies of Agate, Ramsey and Arc. We believe the inventories of the other varieties are adequate for the time being. For Vernal, we estimate the inven- tory on hand will meet the demands for the next three to five years depending on the economics of alfalfa seed production versus other cash crops. Our prim- ary problem at the moment is locating a good foundat ion Agate seed grower. The Ramsey grower should produce a thousand pounds per acre in 1975. There is large acreage of Arc eligible to produce foundation seed. Although the demand for foundation red clover seed is down from previous years, we will start a new filed of pennscott in August to meet any unanticipated future demand . After we get a fix on demand for foundation seed of other red clover varities this spring we will consult with the orginators, consuming states and the seed trade to decide whether additional acreages should be established in late summer 1975. Barring any unforeseen circumstances the production of each of the red clover varieties should be similar in 1975 to that listed for 1974. Each field will be pro- ducing the second seed crop except a new 25-acre seeding of Kenland. A new field of Potomac orchardgrass is under production in Western Oregon. In addition to our inventory the Foundation Seed Project, Oregon State Univer- sity is also holding approximately 10,000 pounds of foundation Potomac antici- pating farmer shift from wheat back to grass seed production. We have arranged to grow 15-20 acreas each of the four Gahi 1 line in 1975. The inventory of Starr will be adequate for two years since the register- ed class is included for this variety. The foundation seed representative in Minnesota will arrange for the production of an additional field of Verdant timothy. Future contract production. For the Foundation Seed Project to provide recurring supplied of foundation seed, it is necessary to make contracts with seed growers for several years production. This is an essential component of the successful program. To do otherwise would not provide a basis for the recurring seed supplies, and in addition would require the plant breeder to devote more of this time to breeder seed production and less to breeding new varieties . Commitments have been made to growers for the production of foundation seed and have informed them of the quality standards that must be met. We feel an obligation to these growers as well as the State Agricultural Experiment Station whose varieties are included in the program and a responsibility to produce and distribute foundation seed in an equitable manner to meet the total demand from the seed industry. Bagging requirements. The bagging requirements were changed based on the recommendations of the Planning Conference last spring. The vote was slightly in favor of the change to single 50 pound units. It was interesting that states purchasing foundation seed generally preferred the 30 pound units. There was almost unanimous agreement that paper bags should not be used even though the bagging costs per pound of seed would be 40 to 50 percent of the cotton bags. About a year ago the cost of double 2.35 osnaburg cotton for 30 pound units was estimated at 4q to 5q per pound, whereas the single 50 pound units would be about 1 l/2q. There will be some operational problems in shift- ing bag size since, for 25 years, the 30 pound unit has been standard except for pearl millet which was 50 pounds. For sometime into the future, we will have both 30 and 50 pound units available of several varieties such as Vernal or Lakeland. Commodity Credit Corporation. In September 1973 the CCC Board of Directors indicated their desire to discontinue acting as banker for the Found- ation Seed Program. This was in line with their general objective to minimize price support stock piling activities . The funds for the Foundation Seed Purchase Program are not in the category of price support. However, it was the general feeling of the Board at the time that withdrawal from the foundation seed activities would be in order. The proposed recommendation of the Board expressed the opinion that foundation seed production responsibilities for public varieties should be turned over to the seed firms. You will recall that Dr. Graumann asked for your evaluation in February 1974. Also AOSCA and the ASTA were asked to review the proposal. Numerous letters were sent to ARS, CCC, the Secretary of Agriculture and Congress requesting continuation of the Found- ation Seed Project. After a thorough review of these communications, a report from the Agri- cultural Research Service, ASCS discussions with members of the seed industry and consultation with other people, Commondity Credit Corporation has advised ARS it will continue its participation in the Foundation Seed Program and have suggested another review the latter part of 1975. Appreciation . In completing this report we want to give special credit to the plant breeders who make available the breeder seed, the State founda- tion seed representa t ives appointed by the Directors of the cooperating state experiment stations, the state certifying seed agencies and seedsmen who make this Project. We offer our thanks--for without these significant inputs the Department's managment costs would multiply several fold; there would be a reduced operating efficiency and it would not be possible to facilitate the production of certified seed of improved forage varieties in this manner. 22 FORAGE FED BEEF CHALLENGES IT PRESENTS By Joseph C. Purcell — ^ Historical Perspective Forage fed beef is not a new concept or a new practice. Prior to World War II, most of the beef produced in the United States moved directly from grass to slaughter. In some areas, these cattle were more than three years old and weighed up to 1,500 pounds -- these were commonly designated as "export" cattle. This term was a carryover from the era in which live cattle were shipped to England. However, beef production systems changed -- gradually during the 1950' s and more rapidly during the 1960's and through 1972 when most of the U. S. beef slaughter excluding cull cows took a turn in the feedlot prior to slaugh- ter (Statistical Reporting Service, U.S. Dept, of Agr . Cattle on Feed (Selected Issues) and 1973. Livestock and Meat Statistics. Stat. Bull. No. 522 and Supplements). The grow-out and finishing period was reduced from three years or more to approximately one year to 18 months depending on the grow-out system. U.S. consumers took to young grain-fed beef like ducks take to water. Between 1950 and 1973, the demand for beef increased 547, per capita. Real (de- flated) cattle prices were nearly the same in 1950 and 1973 with the per capita consumption: 'at 72 lbs. in 1950 and 111 lbs. in 1973 (Ibid. Cattle prices deflat- ed by the U.S. Dept, of Commerce. Survey of Current Business (Selected Issues)). With only two minor exceptions, both the per capita quantity of beef and the real price received by producers increased consistently from 1964 through 1972. Also, the price of cattle increased relative to the price of feed grain during this period (Statistical Reporting Service. U.S. Dept, of Agr. Agricultural Prices (Selected Issues)). This was truly the golden era (1964-72) for the U.S. beef business with everyone reasonable happy including the consumer. Then came 1973 and 1974 when the bubble rose and collapsed for the U.S. beef industry. First we had a consumer rebellion against excessively high beef prices followed by government intervention in the market in the form of price ceilings in early 1973. This led to excessive withholding of all types and sizes of cattle during the first three quarters of 1973. The excessive backlog of cattle broke the market in late 1973. At the same time .grain prices were rising and was further augmented by the extremely small grain harvest in 1974. Cattle feeders suffered heavy losses and responded by drastically reducing the price paid for feeders. Topping it off, the economic recession in 1974-75 has resulted in a sharp decline in consumer demand for beef. 1/ Professor of Agricultural Economics, Georgia Experiment Station, University of Georgia, Griffin, Ga . 23 The History Lesson Was 1974 a fluke with regard to grain production and prices in the U. S.? We do know the size of the crop was weather related, and more normal crops and lower prices are expected in future years. Will the consumer market recover? Yes, if the United States economy recovers. Will the backlog of beef in inventory be worked down? Yes, it is now in process. Where do we go from here? The lessons we have learned are: 1) the U. S. consumer prefers young beef that is firm with a white fat and well marbled, 2) the market requires a uni- form supply of uniform quality beef, 3) a large scale well coordinated feeding- slaughtering system is a highly efficient system, and 4) the U. S. can finish cattle rapidly and efficiently on grain. The beef industry that evolved during the 1960's met all these requirements. Opportunities and Problems Confronting a Forage Fed Beef System The U. S. is a sizeable market for processed beef. This is beef used for hamburger, weiners, bologna and other luncheon meats. Between 1964 and 1973, this market was supplied by cull cows, bulls and stags, and imported beef. The only requirement of this market is healthy bovine animals. The South has the potential to supply this market. The key is least cost production without regard to grade. Cull cows, bulls and stags are by-products of cow-calf and dairy enter- prises. Animals supplying meat for the processed products should be slaughter- ed in the areas where they originate. A considerable part of this type slaughter is boned out and shipped to processing plants in major consuming areas. Pork, imported meats and fat trim from block beef may be incorporated into the final processed products. In that the South contains a large part of the cow herd (both beef and dairy) , the future of the region in this type beef is pretty much assured. Major, but not insurmountable, problems arise in supplying the block beef market from forage feeding systems. Forages can be harvested and fed, or harvested by animals through grazing. Harvested forage requires more mechani- cal energy and labor per unit of weight gain on cattle than grain. Both the quantity and balance of nutrients necessary for high rates of gain are diffi- cult to sustain for long periods of time on grazing systems. A second major problem area is that of supplying the market with a uniform flow of uniform quality animals from forage systems. Nutrients contained in forages are not as concentrated nor as durable as they are in the form of grain. Slaughter animals from grazing systems result in bunched marketings near the end of the grazing season. On a large scale, this results in sharp breaks in price at the peak marketing periods. Moreover, a variable flow of variable quality animals results in an inefficient marketing system and dissatisfied consumers. Requirements for a Successful Beef Industry Relatively high grain prices that prevailed during 1974-75 may have misled people into believing that grain no longer has a place in cattle feeding. Grain is used for purposes other than cattle feeding. Weather related short supplies of grain caused the high prices not necessarily production cost. 24 The real challenge for research is to find the least-cost system of pro- ducing acceptable quality beef through a combination of forage (harvested and grazed) and grain. The key inputs in the beef industry, as well as most other sectors, are energy and labor. Prior to 1973, energy was relatively inexpensive with high cost labor. Now and forevermore both energy and labor will be expensive. No longer can we afford to squander energy as we did in the 1950-72 era. Much of the increase in the forage capacity of the South that occurred during the 1950-72 era came from an increasing use of energy -- mostly in the form of nitrogen fertilizers. A key challenge for future forage systems is to reduce the dependency on commercial nitrogen fertilizers. Obviously, this means incorporating more legume type plants in the forage systems. Corn and alfalfa are still the king and queen in producing nutrients for cattle per unit of land where soil, climate and terrain are favorable. With the increased cost of nitrogen fertilizer, the advantage has probably shifted to alfalfa. We need to now reassess our position in terms of optimum use of energy and labor as well as land in producing beef. Harvested forage systems require more mechanical energy and labor than do grazed forage systems, but yield more beef per unit of land and applied plant nutrients. Regardless of the source of nutrients, a successful beef system require rapid gains from weaning to slaughter weight and finish. Under most any system, gains on growing-fattening cattle of under 2 pounds per day will in- crease the cost of the end product. In contrast, the cow-herd should be maintained on a near maintenance diet 8 to 9 months each year. This requires early weaning of calves. All crop residues (grain, soybeans, peanuts, etc.) and low quality pastures can be utilized for maintaining the cow herd. Future Role of the South in the Beef Industry The future role of the South lies not in a total forage beef system but in a system utilizing less grain than the traditional system that developed during the 1960-72 era. Under a predominately forage system, it would be economical to retain more calves through the growing- finishing period to slaughter. If so, cattle slaughter will increase in the region. A program is needed to monitor and supplement the nutrients in forages (either harvested or grazed) in order to maintain rapid rates of gain. Most likely this would require some grain and protein supplement. Also, a short turn in a feedlot should be considered as a feasible alternative to slaughter- ing directly off a total forage system. The South is rather variable in terms of soils, climate and terrain, and subsequently the seasonality and quality of forage. Slaughter facilities should be located to minimize the cost of assembling live cattle, slaughtering, and distributing the beef to consumer markets. This requires considerable detail on the potential location of slaughter cattle and time of marketing. Detailed data are available on location and size of consumer markets. To be competitive, the South must be efficient through all production and marketing activities. A second requirement is to deliver a uniform product on a con- tinuous weekly schedule. This is not an easy order to fill with a predominate- ly forage beef system. However, it can be accomplished with a high degree of coordination among research-educational institutions and all phases of the beef industry. 25 LITERATURE CITED (1) Anothy, W. B. 1975. Harvested Feed Programs. Feedstuffs, Vol . 47, No. 9: 29 (2) Raunikar, Robert, Purcell, J. C., and Elrod, J. C. 1969. Spatil and Temporal Aspects of the U.S. Food Market. I. Ga . Exp. Sta. Res. Bull. No. 69. 30. Beef . 26 SYMPOSIUM II: PANEL DISCUSSION OF FORAGE-FED BEEF By Carl S. Hoveland — Why Produce Forage Finished Beef? The primary justification for beef cattle, when grain is in great demand for poultry, swine, and direct human consumption, is their ability to convert forages into high quality protein. Rapidly increasing world population, com- bined with crop failures in many areas of the world have in recent years made grain expensive. Even though grain prices have declined, long term energy prospects suggest that more forage will be utilized in the production of beef. Predictions have been made that rising land prices and high grain prices will eliminate beef cattle from good crop land and shift them to land which may have rough topography or be otherwise undesirable for row crops. This has already occurred in many areas of the South. However, much land not well suited for crops can grow excellent pasture which can be used for finishing of beef cattle for slaughter. Many countries in the world produce satisfactory slaughter beef on forage alone. Increased production of forage-finished slaughter beef in the southern USA is certainly possible when it becomes economically attractive to do so. I believe the southern USA will eventually develop large scale production of forage- f inished beef. The big problem is making it an attractive opportunity for location of new slaughter facilities in areas where few or no such plants now exist. If grain prices are low, that day will be delayed. Forage- finished beef must be profitable to the producers, the processor, and retailer. If forage- f inished beef can be produced with low inputs of petro- leum energy, then beef will be available at prices competitive with feed-lot beef. Actually, the feeding system used will not likely be entirely pasture or entirely feedlot but rather a mixture of the two, depending on consumer de- mand, availability of cattle, and cost of energy and grain. How can We Produce Forage-Finished Beef? Warm season perennial grasses such as bermuda and bahia are satisfactory for maintenance of brood cows but do not provide enough digestible energy for rapid growth of steers or heifers (Table 1) . Daily gains of steers grazing Coastal bermuda or Pensacola bahiagrass do not usually gain much over one pound per day. In contrast, digestible energy and daily gains on dallisgrass are generally better although carrying capacity is lower than for bermuda or bahia. 1/ Professor, Agronomy and Soils Dept., Auburn University, Auburn, Ala. 36830. 27 Slaughter grade of animals grazed on these warm season perennial grasses is usually only Standard or Utility. Steer performance on these grasses is much better when clover is present in the sward. TABLE 1 . - -Digestible energy of grazed common southeastern USA pasture species and average daily gain of steers grazing them. Forage Digestible Energy, °L Average daily steer gain, lb. Bermuda & Bahia 45-65 1.0 Dallisgrass 60-70 1.4 Tall Fescue 60-70 1.2 Pearl millet 65-75 1.1 Winter annuals 70-80 1.9 (Rye -ryegrass- Yuchi arrowleaf clover) Warm season annual grasses such as pearl millet and sorghum-sudan hybrids are high in digestible energy and have a high carrying capacity for short periods of time. However daily gains per steer are often no better than on perennial grasses. Tall fescue pasture during its main cool season growth period is fairly high in digestible energy and generally provides daily steer gains somewhat better than that obtained on warm season grasses. However, the toxicity potential with this grass can result in poor steer gains and finish. Animal performance is improved when ladino clover is grown in association with the grass. Cool season annual pastures offer the greatest potential for producing forage-finished beef in the southeastern United States. Various combinations of small grains, ryegrass, and annual clovers can be used. These forages have a digestible energy concentration sufficient for cattle to reach a certain degree of finish. In the lower southeastern USA, a mixture of rye-ryegrass- Yuchi arrowleaf clover can be grazed continuously from November to June. Daily gains of about 2 pounds per day result in 400 pounds of annual gain per steer and slaughter grade of high Good to low Choice. Some Problems in Producing Forage-Finished Beef There are two major types of problems in the production of forage- finished beef: (1) pasture problems and (2) processing and marketing problems. Some of these problems can be alleviated with improved management while others will require further research. Pasture Problems (1) Winter annual pastures, especially on clay soils, can be seriously damaged by hooves of cattle grazing during wet periods in winter. Ryegrass forms a better sod than rye alone and can reduce pugging damage by cattle. However, animals may need to be removed from extremely wet pastures and fed stored roughage. (2) Uneven seasonal distribution of forage production is a major problem when finishing steers on pasture. Unused forage accumulated during 28 a favorable growth period may result in overmature grass of lower nutritive quality and little or no initiation of new leaves. One way to overcome this problem is to stock the pastures at a rate to utilize forage during peak growth periods and supplement with corn silage during periods of insufficient pasture growth. Close grazing of winter annual pastures not only utilizes all the rye forage in late winter and early spring but also stimulates growth of high quality arrowleaf clover and ryegrass. If supplemental silage feed- ing is not possible, then pastures may need to be stocked less heavi- ly and surplus forage during vigorous growth periods can be utilized by beef brood cows. (3) Productive pasture legumes seem to be the key to maintaining good animal gains over a long season as well as reducing the cost of nitrogen fertilizer. Unfortunately, on many soils we do not have satisfactory adapted legumes. We are especially deficient in high quality, productive summer legumes that can grow in association with grasses. Much more research is needed in this area. (4) Perennial grasses, especially warm season species, are too low in digestibile energy, resulting in poor gains and finish of growing animals. Breeding programs now in progress are making progress in developing more digestible grasses. Unless dependable cheap nitrogen is available from a compatible legume or symbiotically fixed in grass roots, large amounts of nitrogen fertilizer will have to be applied to these high quality perennial grasses. The same amount of nitrogen applied to corn grown on good cropland will produce more digestible nutrients per unit area. Processing and Marketing Problems (1) A major deterrent to wide acceptance of beef finished on pasture is that many of these cattle may have yellow fat. Cattle from these production systems are discredited at every level of the marketing system (whether justified or not) because of yellow pigmentation of external fat. (2) Probably the most serious problem with developing a strong forage- finished beef industry is the undependable year around supply of slaughter animals. Winter annual forages are the only pasture species in the South that will permit cattle to reach a considerable degree of finish without supplemental grain feeding. Finishing cattle exclusively on winter annual pastures will result in an over- supply of slaughter animals in late spring and none over much of the year. A supply of slaughter animals at all seasons of the year is essential if this region is to support a significant slaughter beef industry . SUMMARY 1. There is no easy way to produce a slaughter beef with suitable degree of finish year-around on pasture alone in the Southeast. 2. A successful forage- finished beef program currently must depend on: (a) cheap land (c) legumes (b) winter annual pasture (d) supplemental stored roughage (corn silage) . 29 3. Future development of a forage- f inished slaughter beef industry will require further research on: (a) Improved quality warm season grasses and legumes to permit a year- around supply of slaughter animals to processors. (b) Improved quality cool season perennial grasses and legumes with nema- tode and disease resistance. (c) Improved biological fixation of nitrogen by symbiotic bacteria on legumes and grasses. 30 SOUTHERN PASTURE FORAGE CROP IMPROVEMENT CONFERENCE ANNUAL MEETING 1975 Overton Research Center, Texas A & M System Overton, Texas Discussion following panel concerning the production of beef on pasture Mr. Harold Johnson: I would like to express my concern for research to develop a supplement that can be fed to cattle on pasture to change the color of the fat. Quest ion by Dr . Glenn Burton: Can we convince the consumer that the yellow beef is just as good as yellow poultry meat? Dr. Maurice Ray responded that a good example to give was that the Coastal Bermuda dehydrates industry is interested in maintaining a high xanthophyl content in Coastal in order to enchance the shank color in poultry. Response by Dr. Joe Purcell: It does not seem to be as necessary to change the consumer as it is to change the standards so that the yellow fat is not discounted to the producer. Mr. Bill Conrad: How long do you need to feed cattle in dry lot after cool-season grazing in order to get the yellow color out of the fat? Response by Dr. Aaron Baxter: Our research indicates that 49 days is not sufficient time in dry lot to get the yellow color out of the fat. Following Dr. Baxter's comment it was indicated that 60 days on dry lot would be necessary to get the yellow color out of the fat. Comment by Dr. Ray: There appears to be an area difference in the acceptability of yellow fat. Dr. Ray indicated that in his area of the country the packers did not discriminate against yellow colored fat. Dr. Ray emphasized that he was refering to tinted coloring in fat and not to the very deep color that can sometimes appear in older beef cattle. Dr. Marvin Riewe commented that one chain store in his area was offering grass fed beef for 60q a pound less than they were charging for choice fed beef. Dr. Riewe interpreted this to -mean that the marketing channel would be a greater influence on whether the cattle were moved to the feed lot off grass or directly to slaughter off grass. Dr. Joe Burns commented: It may not be too important whether the beef is yellow or white, but more importantly whether the consumer has income to purchase beef. It was emphasized that the total profit chain is important and must be considered with respect to how efficiently beef can be merchandised. Response by Dr. Purcell: The develop- ments in price between low, good and choice steer carcasses is $11 per hundred weight. This means that the final 200 pounds on a steer is worth $90 per hundred weight. Thus, presently it is paying to finish cattle to choice grade. Dr . Tim Taylor : My question is to Dr. Ray. Is the quality of beef affected by preslaughter stress? What is preslaughter stress? Response by Dr. Ray : Preslaughter stress represents that stress to that animal inducted in the hauling and other manipulation of the animal and its carcass during the killing and dressing operation. It is usually the kind of handling the animal is 31 subjected to immediately before it gets to the packer. The management of the animal immediately before slaughter has much to do with the color of the red meat in the dressed carcass. A question with respect to Prime and choice beef from grass and grain, would there be a difference in quality? Response by Dr. Ray: There would be no difference. Would the amount of yellow color in the carcass depend upon when the cattle were pulled off pasture? Response by Dr. Ray: Our cattle discussed above came off pasture in early June. A further comment was made that some data show that cattle coming off wheat pasture in March did not carry fat pigmentation. Based upon this finding it may be that we should select the pro- per time of removing cattle from pasture to slaughter. Another comment was made that the fat is trimmed off carcasses and, therefore, fat color is of little importance. Mr. Bill Smith: Is there an opportunity for mechanical tenderization to improve froage fed beef? Response by Dr. Ray: Some work from Texas A & M University indicates that the way the carcass is hung in the cooler may affect the tenderness of the carcass. Dr. Ray emphasized that anything we do to the carcass adds to the cost and this cost must be justified in improvement in the carcass . Dr. Ethan Holt observed that the consumer reaction recently stopped legislation concerning a change in the meat grading system. He suggested that the action of consumer groups is an important influence on market systems and we must recognize this influential factor in our beef production system. Dr. Holt emphasized that we should develop forage grazing systems in order to main- tain good distribution of forage throughout the year and thus be able to pro- duce quality cattle off pasture. Dr. Holt also emphasized that there was need to develop quality into warm-season perennials so that these crops could be used in sequence with cool-season annual pastures. He indicated that more research was needed in this area. Dr. Carl Hoveland commented that we must seek major improvement in the performance of animals on warm-season perennials. He emphasized that we must manage cattle for rapid growth rate. Because of the high interest cost for money invested that we can not extend the period of time that we keep cattle on pasture. Dr. Hoveland was asked how we might get this increase rate of gain on warm-season perennial pastures. His response was that he did not know, but perhaps Dr. Glenn Burton would like to comment on this subject. Dr. Burton responded that perhaps a legume might be one way to improve cool-season annuals. However, there are serious limitations in legumes with respect to disease and climatic variables. Certainly more research in needed in this area. Question by Dr. Ray: I would like to ask if there is any prospect for an alfalfa that can be produced in pastures? Response by Dr. Burton: In Florida there seems to be nice progress in developing an improved alfalfa. There is the problem of seed production in alfalfa; also there are serious disease problems. Dr. Burton said that he did not think that we have to have a legume in order to get quality in warm-season perennial forages. He stated that management is an important factor in maintaining high quality in forage. Dr. Burton cited the example of improving sorghum quality by selecting to remov'e the gloom. This work was reported in Crop Science; this simple gene change makes a lot of difference in the nutritive value of Sudan grass. The increase of digestibil- ity amounted to 2270. This compares with a 127. improvement in digestibility for Coast-cross Bermuda over Coassal Bermuda. This 22 % increase was reflected in a 307, increase in beef production. 32 Dr. Baxter: I would like to ask Mr. Johnson what he plans to do this fall and winter with his grazing program? Mr. Johnson: I am going to in- crease; I will buy some steers and I will be buying larger steers to put in a pasture by themselves. I believe I can increase my grazing program to improve efficiency in use of my land, machinery, and time. This program doesn't tie a manager down. It permits time to go fishing. Thus, there is great con- venience in carrying out this grazing program. Dr, Horn: My comment is relative to the international market for high quality beef. Are we going to have a turnaround and must we write off our export beef market? Do we need legislative protection? Response by Dr. Purcell : The United States is the largest producer of beef and also the larg- est importer of beef. Dr. Purcell emphasized that we have a large requirement in this courntry for processed beef and about 307, of this is imported. New Zealand, Australia and Argentina have some advantage in producing processed beef and that is particularly because we have a land use requirement in this country. In the Southeast there are opportunities for producing processed beef in contrast to block beef. Marvin Riewe : If we go for processed beef production can we compete with imports or do we need legislation to block the imports for us to get into that? Response by Dr. Purcell: No, we do not have to have regulations. However, there is a contradiction in our import/export laws. These need to be modified. Question by Dr. Burton: Relative economics of the baby beef production as compared with carrying the calf on to heavier weights. Does the industry have to go past the baby beef stage in order to be prof itable . Response by Dr. Purcell : For the short term we are going to slaughter the 600 pound calves. Beyond this short period we have too much cost into the cow/calf. In order to market the calf, then we must carry the calf on to about 1000 pounds slaughter weight. Minimal cost of beef comes from about a 1000 pound animal. It was suggested that the animals need to be grown past weaning. Question had to do with the relationship of stocking rate to beef pro- duction per acre. The question seems to be "Why do you graze the pastures short?" Response by Dr. Hoveland: We graze short to maintain the legume in the sword and nutritional quality of the sword. Reference was made to Mr. Johnson's statement that cattle standing in belly-deep forage did not gain as well as those on short forage. When the sword growth gets out of hand, daily gain drops. It is a complicated thing; less clover in the pasture with more mature leaves causes quality of forage to drop. Question by Dr. Hagen Lippke: Referring to the data presented by Dr. McCarter, at what point on the forage production curve would we maximize beef production? Response by Dr. Hoveland: "The eye of the master fattens the beast." We should adhere to this philosophical concept. Response by Dr. McCarter : Management of the grasses is important and should be related to the management of the legumes. There was further discussion in this area by Drs. McCarter, Hoveland, and Lippke. There comments were primarily stimulated by the information presented by Dr. McCarter in his paper. Not all the comments made at this point were recorded; one interested in this discussion should refer to the paper by Dr. McCarter, especially the graph showing the relationship of forage availability and animal performance. Dr. McCarter cited some data from Dr. Burton where cattle had made an average daily gain of two pounds on Coastal Bermuda at the Homer, Louisiana Station. It was stressed that one could get this kind of gain on steers on Coastal Bermuda where the sword and cattle were properly managed. Dr. Riewe commented that forage availability was an important consideration. 33 Question by Charlie Welch: In the short run we are depending upon a cow/calf production for beef, and I am wondering if we are doing any work to enhance the milk production of the cow. Dr. Maurice Ray: Yes, much effort is being put forth to improve the production of the beef cow. As an example, we are using the beef-dairy crosses to enhance milk production. Comment by Dr. McCarter: It is necessary to give attention to the region when one is selecting the kind of livestock to use. There are differences in animals in respect to geographical areas. Dr. McCarter commented that cattle do selectively graze and may use only about 50% of the forage available. Comment by Dr. Lucas: With respect to Dr. McCarter's diagram, the grazing results would depend upon whether the sword represents one specie or several species. As an example, grazing pressure might need to be regulated to pre- serve legume in the sword. Dr. Lucas also stated that in grazing tests on Coastal Bermuda, changing the grazing pressure on the sword to keep the grass short and vegetative increased the ADG from about 1.3 to 2 pounds. Thus, the management of the animals and the sword has much to do with the animal perfor- mance results one should expect. Question by Dr. Ethan Holt to Dr. McCarter: Could you comment concerning the expected performance of yearling cattle that were placed to graze warm- season perennials after a grazing period on cool-season annuals? Dr. McCarter responded by emphasizing that there would be a difference with respect to whether the calves were spring born or fall born. For spring born calves there would be little delay between weaning and the time the animals could be placed to graze cool-season annuals. In contrast, fall born calves would be weaned from their dams much earlier than they could be placed to graze cool-season annuals. Question by Dr. Homer Wells: If we want to eat beef the year round, why do we have to have our calves born at a particular segment of the year? Response by Dr. Ray: Although for good management we plan our calving program accurately, we have calves available throughout the year. Comment by Dr. Riewe which was not audible on the tape . Comment by Dr. Pratt: Here in the Southeast we can grow forage almost 365 days of the year. It is important that we give our attention to developing forage management systems that fit our various regional areas and that make full use of our great potential for the production of forages. Dr . Riewe : As researchers, it is our responsibility to develop systems of producing beef that are efficient and that utilize our potential for feed production. 34 FORAGE RESEARCH IN THE SOUTHERN REGION: OBJECTIVES, EMPHASIS, AND TRENDS By A. W. Cooper^/ It is a pleasure for me to be with you today at this most important Forage Breeders Work Group. House Resolution 1339 states in part: "as a prudent nation, we make immediate and substantial public investments in agriculture research and tech- nology for the purpose of increasing food production." Secretary of State Kissinger said, before the U.N. General Assembly, that "international, national, and regional research programs must be expanded. Scientific and technical resources must be mobilized now to meet the demands of the year 2000 and beyond." That sounds like agricultural research is basking in a warm, comfortable climate. With our present staffing and funding, we cannot consider these as halcyon days, however. Since 1971 the ARS budget has declined about 27% in constant dollars. There are 200 fewer scientists in State Agricultural Experiment Stations than in 1966. But we should consider the House bill and Secretary Kissinger's statement as a charge and a challenge. As I've said many times, we do have the resources-- the people, the water, and the land--to accept the charge and meet the challenge for a plentiful supply of food and fiber. We must do the best we can with the research funds available to 1/ Deputy Administrator, Southern Region, Agricultural Research Service, U.S. Department of Agriculture, New Orleans, La. 35 obtain the technology needed as conditions change. Work groups such as this one can be a catalyst to improve forage production in the South and to contribute to the technology needed to improve the economics of the Southern Region of the United States. Grass-producing lands cover about one half of the area of the world. These lands protect the environment from erosion, they beautify, and they produce feed. Forage is one of our most important crop commodities, and we need to increase our knowledge about its cultivation. There were more than 21 million acres of unused land in the Southern Region in 1966 that offered great opportunity to expand the livestock industry. No doubt some of this land has been put back into crop production. However, large numbers of acres still remaining idle could be best utilized for forage production. Much land is now underutilized. Cattle are well distributed in the Southern Region. Texas and Oklahoma have the largest number of beef cattle, and North and South Carolina have relatively few. The largest concentration of dairy cows in the Southern Region is in Texas, Kentucky, Tennessee, and Florida. We should increase the population of other ruminant animals in the Southeast. Preliminary figures by the Statistical Reporting Service show that the cattle and calf population in the Southern Region in 1974 was 44.8 million, up 2.6 million over 1973. This adds up to a total farm value in the 13 Southern States of over 12.5 billion dollars. That represents 30% of the total in the United States. Research shows that many areas in the South have the capacity to produce large quantities of a variety of forages to support these animals. However, these forages vary greatly in their concentration of digestible nutrients, and there are great differences in animal response to grazing on the wide variety of species that can be grown. Grasses and legumes, which can be produced on land not well suited for crops, contribute significantly to man's food supply when processed through ruminant animals. Forage- produced beef contains less fat and may be more nutritious than grain-fed beef. In many areas of the Southern Region, beef could be produced--and marketed at a lower cost--on pasture, with little or no grain feeding. In Puerto Rico, milk can be produced successfully on an all grass ration. The South has a greater potential for feed production than any other section of the United States, which suggests a need for more research aimed toward selection of better production systems. Many ARS scientists have told me that their research program could not be carried out effectively without the cooper- 36 ation they receive from the States. I hope that the cooperation is a two-way street. Forages in the South must be integrated with the most highly diversified agriculture in the United States. Few farmers in the South are interested only in livestock. Therefore, livestock and the forages needed to feed them compete with cash crops for land, labor, and equipment. Far too often cash crops receive priority. Last March, I met with the Southern Regional Planning Committee. During the meeting we were pleased to hear from Dr. Ray Corkern, an ERS economist stationed at our Southern Regional Research Center in New Orleans. Ray presented some interesting statistics. I'd like to review a few with you. The per acre yield of silage in the Southern Region is not quite 92% of the national per acre yield. Hay yield is just over 84% of the national yield. The Southern Region accounts for 35.2% of all cattle and calves in the U.S., yet the Region receives only 30% of the total dollar value. One reason for this low percentage is the fact that southern farmers and producers sell their calves at an early lightweight age. The Southern Region is a net exporter of cattle, and the North Central and Western Regions are net importers. If we concentrate on beef cattle alone for a moment, the Southern Region has 46% of the total U.S. beef-cow population, that is, beef cows that have calved, or a total of 22 million head . Dr. Will Butts, Technical Advisor for beef cattle, tells me it would be advantageous to hold calves to about 700 pounds-- called in the industry a "handy weight feeder"-- rather than selling weaned calves weighing 450 pounds. If you disregard last year's market, it can mean 20 to 25% more weight to produ- cers over a long period of time. This production practice could mean considerable savings in grain. Percentages are about the same today as in 1970, when the Southern Region accounted for just over 27% of the total U.S. population. However, the Region accounted for 40% of the total farm population, showing that the highest ratio of farmers to population is in the South. The Southern Region has more resources and practical alternatives to provide year-round feed production than any other section of the United States. Does this fact tell us that we should be directing more research toward selection of better production systems? I think it does and I think we are. ARS is conducting forage research in every Region. The Southern Region has several locations involved in increased forage production. 37 At College Station, Tex. , there are 4 ARS scientists developing technology to improve the productive capacity and nutritive value of range ecosystems for cattle and sheep and for coordinated multiple use. The direction being taken is with ecological and physiological studies in plant communities. They’re concerned with improving varieties and practices for more efficient forage-livestock ecosystems. This work is aimed at reducing livestock production costs and to conserve natural resources . Research by 4 ARS scientists at Raleigh, N.C., is devoted to improving production practices and performance of forage varieties. They are developing grasses and legumes with higher yield and quality, and with resistance to diseases, nematodes, insects, and environmental stresses. They are investigating new cultural practices and utilization of forages for hay, silage, or pasture to reduce the cost of feed for producing livestock products. At Tifton, Ga. , 5 ARS scientists are studying the cytology, genetics, breeding, pathology, and quality of several forage grasses, legumes, and turf grasses adapted to the Southeastern U.S. They work cooperatively with State and Federal plant and animal scientists and utilize the information obtained to develop improved varieties and germplasm sources. Improving forage quality by breeding and management is being emphasized to increase the efficiency of red meat production. Coastcross- 1 bermudagrass , capable of increasing average daily gains and liveweight gains per acre by one-third, is the first varietal product of this research. At Tifton, Ga. , our scientists are striving to improve equipment to manage forages, to find improved methods and equipment to increase the drying rate of forage, and to develop utilization of solar energy to replace some of the fossil fuel required for mechanical drying. Other objectives at Tifton are packaging, handling, transporting, storing, and feeding of hay and silage. Research is also being conducted to improve the digestability of forage crops. There is other research at Tifton that I would also like to mention. One is the important work to develop safer, more effective chemical methods for controlling insects on forages and legumes, which parallels the research on cultural and management practices to reduce insect populations. Another area is the search for, and the research on, parasites, predators, and insect pathogens for possible use as control agents. The whole idea is to utilize new and radically different insect control methods and mold them into suitable and efficient pest management systems. 38 At Mississippi State, the objectives of one ARS scientist include improving grass and legume seed efficiency for producing forage, pasture, range, and turf. He wants to assure that domestic and foreign markets have recurring supplies of high- quality seed of improved varieties. There are 8 ARS scientists at Athens, Ga. , working on forage research, developing improved methods for feeding dairy cattle. The emphasis is on production and storage of high quality forage. Scientists are also evaluating the efficiency of pelleted forages. In addition, there is one ARS scientist at Temple, Tex., working on development of new varieties of weeping lovegrass having improved forage quality, winter survival, drought toler- ance, and seed production. One ARS scientist at Woodward, Okla., devotes his efforts to developing range improvement tools, improved annual and perennial pastures, and ranching practices for increased quality and quantity of forage. The objective of the ARS scientist at Stillwater, Okla., is to develop efficient cultural and management practices to provide maximum reproductive potential of bermudagrass , weeping lovegrass, switchgrass, and other introduced and improved native grasses. At Poplarville, Miss., one ARS scientist cooperates with MAFES scientists on basic research on forages, including measurement of regrowth potential, quality, and yield of perennial grasses in relation to animal performance. An ARS scientist at Clemson, S.C., studies methods to increase longevity of white clover stands and improved distri- bution of forage production by breeding varieties with heat and drought tolerance, improved resistance to pests, and improved persistence . Studies on forage plants for use in maintaining a vegetative cover and for providing a potential for economical use of surface mine spoils is the emphasis of one ARS scientist at Blacksburg, Va. Two ARS scientists at Lexington, Ky. , direct their work toward development of superior varieties of tall fescue with high nutritive value, palatability , disease resistance, and yield . One ARS scientist at Gainesville, Fla., is studying the specific biochemical processes affected in forage species when 39 growth is adversely affected by environmental stresses. ARS , in cooperation with University of Florida scientists, has recently placed emphasis on exploring the possibility of nitrogen fixation in tropical grasses. Not all of the scientists mentioned are able to devote full time to forage-research problems, but ARS participation in forage work in the Southern Region involves approximately 32 scientific man years. This is just a brief summary of the broad areas of research going on in ARS in the Southern Region. Our colleagues in the other Regions are also working to reinforce the overall effort to improve the production, efficiency, and utilization of forages . Forage research i_s difficult, time consuming, and expensive. Cereal research is concerned with one harvest a year of a reasonably uniform product. On the other hand, forage research requires many harvests per year of a highly variable product. Forages have all (and perhaps more) of the pest problems of the cereals, plus the additional problems of seed production. In addition to the emphasis and objectives in forage research, I’ve been asked to touch upon the trends; I presume this means future needs. Heretofore, most research focused on component parts of the milk or forage-beef production systems. In the future we need to focus not only on the behavior of individual system components but also on the mechanisms whereby the components are coupled with each other, for example, the interfacing of sward and animal. Thus, we need to emphasize a fully integrated, interdisciplinary approach to forage-animal production problems. Several areas of forage research that will receive special attention are-- Collection, evaluation, and preservation of forage species to provide germplasm for improving forage crops. Breeding of warm- and cool-season forage species for superior nutritive value and improved persistence. Development of equipment and techniques for improving the establishment and management of small-seeded grass and legumes . Identification of the extent of stand, yield, and nutritive losses from weeds, insects, diseases, and other pests and the development of new and improved chemical, biological, and cultural methods to control these pests. 40 Development of technology for improved establishment of symbiotic relationship. Rhizobia strain evaluation for tolerance to high tempera- tures and acid soils. Development of forage systems for meat and milk production. Evaluation of promising components of crossbred cow-calf test units, development of better breeding methods, and breeding of cattle that will better utilize forages rather than concentrates. And finally, in relation to cool season grasses, development of a creeping winter grass for the coastal plains similar to the bluegrass that is so effective in the limestone soils . Those are just some of the challenges that are ahead. As we look into the next 3 to 5 years and further, it seems obvious that even greater demands will be placed on our land resources for the production of food and grain crops which will mean less acreage for livestock and forages. This inevitability does not mean, however, that our need for forages will decrease. The dairyman who is making a profit today has a feeding program based soundly on stored forages: silage, haylege, or hay. The cattleman, to stay in business, must rely heavily on grazing for beef production. The demand for meat and milk will remain strong. The beef and dairy industries of the future will be based more squarely upon the feeding of forages than they do today, a result of the high cost of grain and protein supple- ments. Pressures on land resources will mean that American farmers will have to do a better job of producing forages. Higher production per acre is needed, and lower cost per unit of feed is essential. When you and your colleagues have accomplished these goals you will have solved critical economic problems facing the South while helping to meet the food needs of the world. I wish you a most successful meeting. 41 A REGIONAL APPROACH TO BREEDING FORAGE CROPS By J . E . Halpin — / INTRODUCTION The four key words provided are advantages, disadvantages, limitations, and mechanics. Disadvantages and limitations would be closely related. Let us proceed to consider the negative first and then proceed to the more positive aspects of the topic. If the scientist prefers to build an "Ivory Tower" image around himself then regional research is not the answer. One might paraphrase this by saying, "I prefer to be here by myself, although I may be in the dark." In today's world, this makes about as much sense as a person trying to cover up the fact that he has Syphillis. Another way of looking at it is that if you cooperate, someone may find out about your limitations. Certainly we would not want that to happen. At the same time, the will and forcefulness of others may affect your work, either its direction or its load. People may question your selec- tion of projects and priorities, even your approaches. The results could be that your pet project does not receive the acclaim that you had hoped for and instead of getting comfortable in science, a degree of professional dis- comfort might result. Enough for the negative. Turning to the advantages of the regional effort we must keep in mind that forage crops are diverse in habit, characteristics, problems, and purposes. Nonetheless, in the philosophical vein there are certain advantages which must be considered. The famous Pound Report noted that in agricultural research, the regional research program of the state stations had provided more publications per SY of time than any segment in the public agricultural area. This might be the re- sult of the second advantage I have for you: social. The very fact that the regional research program involves cooperation with others, often from different disciplines and certainly different environments, provides an impetus which may not be available in other climes. Likewise as different disciplines come together, each brings its own "laws" or "modes of operating" which have built up over the years and may not be totally valid. Thus a check and balance system might be provided for the conscientious investigator who desires to take advantage of the system. There is one area in limitations which is unique and deserves separate understanding: that of funding. It is correct that under the Hatch Act, cer- tain of the funds appropriated thereunder are earmarked for regional research. However, this does not guarantee that participating in a regional research project will mean necessarily extra funds become available to the investigator. 1/ Director-at-Large , State Agricultural Experiment Stations, Southern Region, Clemson, S. C. 29631. 42 Levels of current funding for regional research projects in general indicates that much more non-regional Hatch and even more state appropriated funds are placed on the regional research program by the station directors than the law requires. As a result, it is possible that for an individual scientist, involvement in a regional research project may only result in a change in funding source, not actual funding level. However, experience has shown that often times development of regional research projects can result in renewed attention to a project area and the administration of funds providing extra increments of dollars as means of supporting the concepts which the scientists collectively are undertaking. The mechanics of establishing a regional research project are straight forward and spelled out in a publication by the Cooperative State Research Service entitled, "Manual of Procedures for Cooperative Regional Research." Incidentally, this manual is currently undergoing revision but the bulk of its contents are quite well established. Assuming that a group of scientists have reason or belief that a regional research project might be developed, they can follow the various steps in the manual and although it appears to be an administrative hassle to do so, actual- ly the effort involving the initiation of a project is not that great. To initiate a topic, a letter to a station director providing a paragraph on concept and need can result in his initiating, through SRRC, a recommenda- tion for an area of work. Once an area of work has been approved, steps in establishing a regional research project can follow. To do so is certainly not "Ivory Tower" but truly positive, in spirit and action. 43 SIGNIFICANT ADVANCES IN PLANT TISSUE AND CELL CULTURE By Earlene A. Rupert — The usefulness of cell and tissue culture in plant improvement was pro- posed by Haberlandt as early as 1902 (_14) , but significant progress was delayed for several decades by the absence of biochemical parameters for the nutritive and physical environments in which isolated cells and tissues could survive and reproduce. The urgent need to equalize the relationship between population growth and food supply has inspired recent intensive collaboration among basic and applied physiologists, biochemists, molecular geneticists and plant breed- ers in this new area of genetic engineering. Excellent and detailed reviews of their accomplishments and the application of these to agricultural problems have been published between 1972 and 1975 (JL, _3 , 12 , 17 , 21 , 23 , 29 , 30 , 31) . Most living tissues can be excised and cultured. Many, such as embryonic tissue, apical meristem and leaf mesophyll, are capable of expressing the complete range of genetic information found in a zygote. General _in vitro culture techniques for higher plant tissues were developed by Phillip White during the middle decades of this century and are summarized in his classic manual (32) . Since the discovery of auxins, cytokinins and gibberellins in the fifth and sixth decades, cultures have been stimulated to regenerate new plants, although, frustratingly , each species, often each variety, seems to require a different combination of mineral salts, sugars and growth regulators. During the last five years, enzymatic removal of the pecto-cel lulose cell wall has produced a membrane-bound protoplast capable of incorporating plastids, bacteria, viruses, exogenous DNA and polystyrene balls, and also capable of fusing with related and unrelated neighbors to form "somatic hybrids" (_30) . Higher plant biologists need envy the facile transformations of species report- ed by the microbial geneticists no longer! Meristem culture Plant reproduction through meristem culture already is a common and highly profitable practice among nurserymen specializing in horticultural species such as orchids, carnations, and chrysanthemums. Stem apices retain their organo- genetic potentiality until the flowering process is initiated. Morel and Wetmore (22) first grew fern apices on mineral salts and sugar water in 1949, but had little success with other species (sunflower, dahlia, potatoes) until gibberellins and potassium were found to stimulate apical organogenesis. In 1964 Morel (20) extended the technique to orchids, whose meristem, on an agar- based medium, produces numerous embryo- like protocorms, each of which can be 1 / Associate Professor, Department of Agronomy and Soils, Clemson University, Clemson, S. C. 29631. 44 subdivided ad infinitum to produce plants identical to the original stock. Some 22 orchid genera are propagated currently from shoots, leaf tips and young inflorescences (2_3) . Murashige (23) has listed 151 species and varieties distributed among 54 additional plant families with demonstrated potential for clonal multiplication through meristem tissue culture. Chrysanthemums are a striking example of the efficiency of shoot meristem culture. Reproduction through conventional cuttings may give 30,000 6-inch plants in one year; reproduction via shoot culture on synthetic media can give 9 million; via shoot-callus-cell culture the number can be increased to 90 billion in the same time span (1_0, 11) . Moreover, four-year-old cultures continue to produce normal plants. The multi- plication of hybrids has been especially profitable: An F^ hybrid asparagus derived from crossing diploidized haploid lines has been multiplied and distri- buted by Morel (2_1) . Careful removal of differentiated tissue surrounding the meristem has produced virus-free lines of those above and many other species, i.e., straw- berries, geraniums, dahlias, potatoes, and white clover. Foresters recognize that these new procedures may ease their struggle with the long life spans of trees and are actively developing culture media for species and hybrids. There is no doubt that many of our forage crops can be manipulated to advantage in similar fashion once the specific culture conditions have been defined . Callus and cell suspension cultures Callus and cell suspension cultures are easily obtained from hypocotyl , pith, endosperm, meristem and other tissues, and may be maintained in active reproductive condition for many years by replenishment of nutritive substances. However, with a few exceptions such as the model plants carrot, tobacco and sugarcane, the embryogenic capacity of these cultures deteriorates rapidly and they have not proved especially useful yet in clonal multiplication (23) . Cultures of sugarcane, in which organogenesis seems to be an endogenous capaci- ty, have been the source of several new cultivars from pith and inflorescence. These vary in genotype and chromosome number from the parental clones. Resis- tance to leaf scale and eyespot has been isolated from cane cells treated with gamma irradiation (J_6, _18, 2_5) . Similar intrinsic variability and regenerative capacity have been well -documented for tobacco. Considerable commercial interest has developed in the use of chemostatical- ly maintained cell suspensions as a means of mass production of physiologically active substances such as the anti-cancer drug campothecin from Campotheca , virus inhibitors from Phytolacca , napthoquinone pigments from Lithospermum (19), and insulin from Mormordica. Regulation of the production of these compounds through tissue selection and substrate fromulation has been proposed. Anther culture The development of haploid plants from agar-cultured post-meiotic anthers of Datura innoxia was first reported by Guha and Maheshwari in 1964 (13). In a similar manner, Nitsch and Nitsch (26) obtained large populations of haploid tobacco plants from which homozygous diploids were obtained by both natural and colchicine doubling. Recently, Sunderland (3_1) listed 12 crops species for which anther culture has been from 1-100% successful (Table 1); 5 of these 45 belong to the family Solanaceae, 4 are cereals and most fall near the 1% pro- duction level. Apparently, the anthers of few species contain the regenerative capacity of tobacco and perfection of culture techniques may be painfully slow. TABLE 1. --Haploid plants from anthers or pollen Order Family Genus Species DICOTS Rhoeadales Cruciferae Brassica oleraceae and x alboglabra Arabidopsis thal iana Geraniales Geraniaceae Pelargonium hortorum Tubif lorae Solanaceae Atropa belladonna Lycopersicon esculentum pimpinellif ol ium Capsicum annuum Datura innoxia metel meteloides Nicot iana tabacum et al . MONOCOTS Graminiales Gramineae Oryza sativa Lol ium multif lorum Lol ium L. multiflorum (4x) x Festuca x F. arundinaceae (12x) Hordeum vulgare Triticum Tr iticale aestivum Aegilops caudata x umbel lulata Setar ia ital ica Liliales Lil iaceae Lil ium longif lorum From: Smith, H. H. 1974. Bioscience 24: 269-276, However, the time-saving offered plant breeders, particularly those working with long juvenile periods, by the immediate production of true-breeding off- spring from Ft hybrids, would be of great value (29) . Kasha (_17) has used successfully a different haploid technique in breeding barley. F^ hybrids of Hordeum vulgare varieties are stimulated to produce hap- loid embryos by pollination with H. bulbosum, a perennial species. Embryos are cultured in the laboratory, treated with colchicine, and the resultant homozy- gous diploid lines are field-tested without concern for further segregation. Varieties are ready for release three years after the initial cross. 46 Protoplast culture, fusion, and transformation Manipulation of the nuclear and cytoplasmic organelles of higher plants has been impeded until recently by the structural characteristics of the cell wall. Since Cocking' s first release of living naked protoplasts after enzymatic digestion of the walls of tomato root tips (6), protoplasts have been obtained from fruit, leaves, roots, root nodules, endosperm, flower petals , tubers and other organs of many species (1) . Transformations and insertions of nuclear and cytoplasmic organelles and fusions of somatic cells are no longer unusual. Somatic hybridization of cultured mouse cells was observed by Barski et al. in 1960 (2^, and of man with mouse cells by Harris and Watkins in 1965 (15). Intra- and interspecific plant cell fusions were reported first between corn and oat root-tip protoplasts after treatment of mixtures with sodium nitrate in sucrose solution (2_8) in 1970. Many researchers since have obtained fusions among closely and distantly related species (Table 2) (_1, 12) . Among these are soy- bean fused with barley, corn, pea, rape, and alfalfa. Sodium nitrate has been replaced by a more effective aggregator, polyethylene glycol. That hybrids can be regenerated from fused protoplasts was demonstrated elegantly by Carlson et al . (5) with a "parasexual" hybrid between Nicotiana glauca and N. langsdorf ii . Leaf mesophyll protoplasts from complementary nutritionally dependent strains were fused to produce a hybrid. Protoplasts were plated onto a medium inadequate for the survival of cells of either parent. Plants obtained from fused cells were identical with interspecific hybrids obtained by traditional cross-pollinations. Extensive development of wide new hybrids from protoplast fusion undoubted- ly will be limited by the nature of interspecific differences and will probably provide little competition for traditional methods of hybridization. In addi- tion, development of fusion hybrids is limited presently by the lack of selec- tive media for elimination of non-fused cells, by the lack of methods for regeneration of whole plants, and by the rarity of nuclear fusion itself after cell fusion (Table 3) . In 1969 Nass (^4) reported the incorporation of spinach chloroplasts into animal cells where they retained their identity and divided normally, demon- strating the autonomy of these plast ids- -and giving rise to facetious speculations by the press on the creation of photosynthetic animals. Carlson (_3, 4) inserted normal chloroplasts into albino tobacco protoplasts where they continue to function and reproduce, suggesting possibilities for intro- ducing improved photosynthetic pathways into many of our crop plants. Protoplasts will incorporate various other foreign substances by invagina- tion of the plasmalemma during cell wall removal. Included are viruses, bacteria, and exogenous DNA. Precise studies of infection, gene complementa- tion and enzymatic action have been faciliated by protoplast availability. Exogenous DNA, however, is usually degraded rapidly by nucleases and currently reported permanent effects on plant development are still questionable. Incorporation of Rhizobium and Agrobacterium into protoplasts has had repeated success, but as yet no new symbionts have been regenerated. Legume root-nodule protoplasts containing packets of bacteria have been extracted by Davey et al. (_7, 8) and progress made in inducing their fusion with non-legume protoplasts (2_7) . Effectiveness of new associations can be tested by acety- lene-ethylene reduction during culture on a nitrogen-free medium. 47 TABLE 2 . - -Intergerteric plant protoplast fusion and heterokaryocy te division SOURCE OF PROTOPLASTS Leaf mesophyll Cell culture Barley (Hordeum vulgare) X soybean (Glycine max) Pea (Pisum sativum) X Vicia haiastana Corn (Zea mays) X soybean (Glycine max) Pea (Pisum sativum) X soybean (Glycine max) Rapeseed (Brassica napus) X soybean (Glycine max) Alfalfa (Medicago sativa) X soybean (Glycine max) Sweet clover (Melilotus alba) X soybean (Glycine max) Chick pea (Cicer arietinum) X soybean (Glycine max) Angelica archangelica X carrot (Daucus carota) From: Gamborg, 0. L. , et al. 1974. Can. J. Genet. Cytol. 16: 737-750, TABLE 3. --Examples of protoplasts in which cell regeneration and division has been observed Systematic Common Name Cell Origin Ammi visnaga (L.) Lam culture Bromus inermis Leyss. Brome grass culture Cicer arietinum L. Chick pea leaf Brassica napus L. Rapeseed culture, leaf Daucus carota L. Carrot culture, leaf Glycine max (1) Merr . Soybean culture Linum usitatissimum L. Flax leaf Medicago sativa L. Alfalfa leaf, culture Melilotus alba Desr. Sweet clover leaf Phaseolus vulgaris L. Bean leaf, culture Pisum sativum L. Pea leaf Pisum sativum L. Pea culture, shoot tip Vicia haiastana Grossh. cul ture Vigna sinensis L. Cow pea leaf From: Gamborg, 0. L. , et al . 1974. Can. J. Genet. 16: 737-750. In addition to new symbiotic relationships, there is the possibility of cryptic transfer of the nitrogen- fixing operon to new species by means of trans- ducing bacteriophages. Apparently, Doy et al . (9) already have been able to transfer the galactose operon from Escherichia coli to haploid Lycopersicon and Arabidopsis callus by means of a bacteriophage. They have coined a new term, " transgenosis" , to describe the event. One can visualize a combination of genes from Rhizobium, Azotobacter , mycorrhizal fungi and blue-green algae which, as either plasmid-like symbionts or structural components of the plant 48 genome, might go far toward liberating agriculture from the expense of applied fertilizers . The preservation of germplasm through liquid nitrogen freezing of protoplasts or cell cultures is of considerable potential importance . Periodic costly replace- ment of banked material through seeding or vegetative propagation with the inevitable loss of genetic variability to disease and weather might be avoided. Normal plants have been obtained from carrot and other species which have re- sumed mitotic activity after prolonged freezing. The use of these microbiolo- gically sterile tissue cultures in plant introduction may revolutionize our quarantine limitations. At the same time they promise safe and efficient means of maintaining while containing cultures of infectious organisms such as viruses and nematodes. Plant breeding can be aided enormously time-wise and space-wise by labora- tory techniques allowing for early screening for photosynthetic pathways, heterotic combinations, resistance to pest toxins, protein synthesis, etc. Chromosomal and genetic variability is characteristic of many kinds of cell and callus cultures ; regeneration from single cells with or without the use of mutagens would allow economical study of and selection among variants on a large scale and might facilitate recovery of diversity lost during past ages of selection. Use of haploid cultures in these experiments would avoid lengthy selection against recessive lethals. In summary, it is clear that spectacular advances in the areas of plant improvement and plant growth in the near future may be achieved by manipulation of cultured plant cells and tissues through the processes of reproduction, fusion and regeneration, and by accessory studies of physiological activities at the cellular level. Regeneration of whole plants from cultured cells is the major remaining unsurmounted barrier to realization of an infinite potential contribution to agriculture. LITERATURE CITED (1) Bajaj, Y. P. S. 1974. Potentials of protoplast culture work in agriculture. Euphytica 23: 633-649. (2) Barski, G., Sorieul, S., and Cornefert, F. 1960. 1960. Production dans des cultures in vitro de deux souches cellulaires en association de cellules de caractere hybride. C. R. Acad. Sci. (Paris) 251: 1825. (3) Carlson, P. S. 1973. The use of protoplasts for genetic research. Proc. Nat. Acad. Sci. (USA) 70: 598-602. (4) Carlson, P. S., and Polacco, J. C. 1975. Plant cell cultures: genetic aspects of crop improvement. Science 188: 622-625. (5) Carlson, P. S., Smith, H. H., and Dearing, R. D. 1972. Parasexual interspecific hybridization. Proc. Nat. Acad. Sci. (USA) 69: 2292-2294. (6) Cocking, E. C. 1960. A method for the isolation of plant protoplasts and vacuoles. Nature 187: 962-963. (7) Cocking, E. C., and Peberdy, J. F., Eds. 1974. The use of protoplasts from fungi and higher plants as genetic systems. A handbook. University of Nottingham, Nottingham. 49 (8) (9) (10) (ID (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) Davey, M. R. , Cocking, E. C., and Bush, E. 1973. Isolation of legume root nodule protoplasts. Nature 244: 460-461. Doy, C. H., Gresshoff, P. M. , and Rolfe, B. G. 1973. Biological and molecular evidence for the transgenosis of genes from bacteria to plant cells. Proc. Nat. Acad. Sci . (USA) 70: 723-726. Earle, E. D. , and Langhans, R. W. 1974a. Propagation of Chrysanthemum in vitro. I. Multiple plantlets from shoot tips and the establishment of tissue cultures. J. Amer. Soc. Hort. Sci. 99: 128-132. Earle, E. D., and Langhans, R. W. 1974b. Propagation of Chrysanthemum in vitro. II. Production, growth and flowering of plantlets from tissue cultures. J. Amer. Soc. Hort. Sci. 99 : 3 5 2 - 358. Gamborg, 0. L. , Constabel, F. , Fowke, L. , Kao, K. N., Ohyama, K. , Kartha, K. , and Pelcher , L . 1974. Protoplast and cell culture methods in somatic hybridization in higher plants. Can. J. Genet. Cytol. 16: 737-750. Guha, S., and Maheswari, S. C. 1964. In vitro production of embryos from anthers of Datura . Nature 204: 497. Haberlandt, G. 1902. Kulturversuche mit isolierten Pf lanzenzellen. Sitzber. Akad. Wiss. Wein, Mathnaturw. Kl . Ill: 69-92. Harris, H. , and Watkins, V. F. 1965. Hybrid cells derived from mouse and man. Artificial heterocaryons of mammalian cells from different species. Nature 204: 4971. Heinz, D. J., and Mee, G. W. P. 1969. Plant differentiation from callus tissue of Saccharum species Crop Science 9: 346-348. Kasha, K. 1974. Haploids from somatic cells. Proc. 1st Intern. Symp . Haploids in in Higher Plants: 67-87. Mee, G. W. P., and Heinz, D. J. 1969. Gamma irradiation of sugarcane callus tissue. Sixth Ann. Rep. Hawaiian Sugar Planters' Assoc. Misawa, M. , Sakato, K. , Tanaka, H. , Hayashi, M. , and Samejima, H. 1974. Production of physiologically active substances by plant cell suspension cultures. Proc. 3rd Intern. Congr. Plant Tissue and Cell Cultures: 405-432. Morel, G. 1964. Tissue culture - a new means of clonal propagation of orchids. Bull. Am. Orchid Soc. 33: 473-478. Morel, G. 1972. The impact of plant tissue culture on plant breeding, Sixth Congr. Eucarpia: 185-194. Morel, G., and Wetmore, R. H. 1949. Growth and development of the shoot apex of Adiantum pedatum nutrient agar. Amer. J. Bot. Suppl. 36: 805-806. Murashige, T. 1974. Plant propagation through tissue cultures. Ann. Rev. 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The cultivation of animal and plant cells:. The Roland Press Co., New York. 51 EXPLORATION AND COLLECTION OF PASPALUM SPECIES IN SOUTH AMERICA By Byron L. Burson — ^ 2/ In November 1974 Dr. W. R. Langford — and I were asked by the United States Department of Agriculture to travel to South America for the purpose of collecting native forage grasses and legumes. My primary interest was the collection of Paspalum species, especially different forms of dallisgrass, P. dilatatum Poir. Since common dallisgrass reproduces by apomixis and essential- ly no improvement has been made by conventional breeding methods, our objective was to find sexual forms of dallisgrass. Due to the increased cost of commer- cial fertilizers and the increased interest in forage legumes, Dr. Langford's major concern was the collection of native legumes. We left the United States in early January 1975 and returned at the end of February. Material was collected in southern Brazil, Paraguay, and Uruguay. Initially we had planned to collect in northern Argentina; however, due to the unstable political situation in that country we were unable to collect. A maximum amount of plant diversity was anticipated in this region of South America because it is generally considered the center of origin of dallisgrass and other Paspalum species. OBJECTIVES The major objectives of the plant exploration trip were to: (a) locate and collect as many diverse forms of dallisgrass for the purpose of securing a highly cross- fert ile , sexual type; (b) collect as many different Paspalum species as possible: (c) collect any other species of grasses which appear to have potential use; (d) collect as many different native legumes as possible. In addition to the above objectives we received a number of requests for other species which are grown in that area of South America. We also collected nodules from some of the legumes obtained and soil samples from the root zone of grasses which were suspected of being associated with free living nitrogen fixing organisms. I / Associate Professor, Department of Agronomy, Mississippi Agricultural and Forestry Experiment Station, Mississippi State University, Mississippi State, MS 39762. 2/ Regional Coordinator S-9 Committee, Agric. Res. Serv., U. S. Depart- ment of Agriculture, Southern Regional Plant Introduction Station, Experiment, GA 30212. 52 GENERAL PROCEDURES Upon notification by the USDA that the trip was approved we contacted different people in each country for assistance in making arrangements or referral to someone who would be of assistance. Our itinerary was such that we first collected material in Rio Grande do Sul, the southern most state in Brazil. Then we went to Paraguay, Uruguay, and returned to Rio Grande do Sul . Upon arrival in each country one or two days were spent with prearranged contacts concerning the best locations for exploration and collection, securing maps, interpreters and a vehicle, visiting herbaria, and arranging for the mailing of the plant material. In each country a person who was knowledgeable of the native grasses and legumes accompanied us. This person also served as a driver and interpreter. Although our means of transportation was normally by car or jeep, it did vary from horseback to private airplane. At each collection site the collection number, species collected, plant description, location, soil type, and any other pertinent information concerning the site or plant were recorded. Seed were dried, threshed, and packaged for mailing. The soil was washed from the roots of the vegetative material and then packed in sphagnum moss and placed in a plactic bag for mailing. All of the plant material collected was sent to the United States by diplomatic pouch and then forwarded to the U.S.D.A. plant Inspection Station in Washington, D. C. for processing . EXPLORATION AND COLLECTION We flew to Porto Alegre , Brazil, the capitol of Rio Grande do Sul. Dr. Roger Hanson, who is with the University of Wisconsin U. S. AID program, was our contact and provided us with climatological and soil maps of the state. He also arranged a meeting with Dr. Ismar Barreto, an agronomist with the Universidade Federal de Rio Grande do Sul. Dr. Barreto is quite interested in Paspalum taxonomy and was very helpful in indicating the best areas to collect, location of different species, etc. He obtained a vehicle from the University for our travels and provided the services of Mr. Arnildo Pott, a taxonomist with interests in range management. Porto Algre was used as a base of operation while collecting in that area. Then we went north to Vacaria and used it for a base of operation for several days. This was an area where we suspected considerable variability in dallisgrass. We started finding the yellow-anthered biotype of dallisgrass just north of the Rio das Antas. We found several different forms of dallis- grass in the Vacaria area. There were types which appeared to be intermediate between yellow-anthered dallisgrass and vaseygrass, P. urvillei Steud. It was in the Vacaria area where we first saw the converting of native pastures to cultivated crop land for soybeans and wheat. Undoubtly valuable germplasm was being lost because of this; however, we were soon to see that overgrazing by livestock probably resulted in even a greater loss of germplasm. We then explored and collected in the vicinities of Bom Jesus, Sac? Francisco de Paula, and Torres. We returned to Porto Alegre and prepared the plant material for mailing. We flew from Porto Alegre via Sa’o Paulo to Asuncion, Paraguay. Mr. San- ford White and Dr. George Ellis of the U. S. AID mission gave us much assis- tance. They provided an AID vehicle for our travels and also obtained per- mission from the Paraguayan Minister of Agriculture for two Paraguayan 53 agronomists to assist us on our trips. Before starting collecting, we reviewed the herbarium specimen at the National University and discussed the distribu- tion of grasses and legumes with the Paraguayans. Because of the distribution of roads in Paraguay we used Asuncion as our main base of operations. All of the grasslands around Asuncion and in the Southern part of the country were severely overgrazed. This was also true along the roadsides. The cattle density in this area was the highest encount- ered on the trip and severely affected our collection. The Chaco region comprised the northwestern section of the country. It is all of the area west of the Uruguay River. The lower portion is a sub-tropical savanna; however, further to the northwest it becomes less tropical and is more of a desert shrub. P. alcal inum Mez is a species used in the Chaco. Buffelgrass, Cenchrus ciliar is L. , was widely used in the upper Chaco and appeared to be the best adapted forage grass we encountered in this area. There had been little rainfall in the Chaco and in the southwestern part of the country which affected our collections. The temperature was in excess of 100°F every day we were in Paraguay and was 115°F the days we were in the Chaco. Eastern Paraguay had more rainfall; however, since most of it was recently cleared jungle, there were limited pastures of any size. We were fortunate in that Dr. Anibel Heisecke, a Paraguayan rancher, provided an airplane for us to fly to his ranches to search for grasses. Two of his sons had attended Texas A & M University and Dr. R. C. Potts, Associate Dean at Texas A & M, was responsible for this contact. This provided us an opportunity to explore in areas otherwise inaccessable . At one ranch there were no motorized vehicles so we traveled by horse. We flew to six ranches at different locations in the country. The most common Paspalum species in Paraguay were P. notatum Flugge, P. pi icatulum Michx. , P. ro jas ii Hack., and P. guenoarum Arech. We saw very little dallisgrass which suggests that it is not native to this area of South America and very little has been introduced. Seed from 143 plants were collected and this included 89 Paspalum accessions. Since we were unable to collect in Argentina, we flew from Asuncion to Montevideo, Uruguay. Our contacts were Dr. Bernardo Rosengurtt, an agrostol- ogist with the Universidad de la Republica, and Mr. Juan Millot, an agronomist at an experiment station near Colonia. Upon arriving we underwent the normal orientation with them. They provided transportation for us and either one or both accompanied us during our travels. We used Montevideo, Colonia, Paysandu, and Tacauremb^ as our bases of operation. We were able to cover most of the country. However, there was a severe drought in the upper two- thirds of the country. It was the worst in the areas of Melo, Tacuarembo and Rivera. This along with heavy grazing pressure severely limited our collections. In north- ern Uruguay we encountered temperatures in excess of 110°F. Due to the drought and overgrazing, we had the most success in areas inaccessable to cattle and sheep. These were small fenced areas and railroad right of ways. A number of diverse forms of dallisgrass were found in Uruguay. The area of maximum diversity was near Minas in the south. It was interesting that the yellow- anthered forms of dallisgrass were found only in the southern third of the country. However, more different Paspalum species were found in the north- ern part of Uruguay. In spite of the deleterious conditions for collecting plant material, a total of 231 collections were made which included 111 Paspalums . We flew from Montevideo to Porto Alegre, Brazil to complete the explora- tion of Rio Grande do Sul. After securing the services of Mr. Pott we rented 54 a vehicle and explored the southern half of the state. Rather than having a base of operations we traveled to Pelotas, Bage, Dom Pedrito, Uruguaiana, Alagrete, Sao’ Gabriel, and Guaiba. We were able to collect several species that were unavailable in Uruguay because of the drought. Several forms of yellow-anthered dallisgrass were found near Bag/. Prior to leaving Porto Alegre we made arrangements to visit with Dra. Johanna Dobereiner at the experiment station at Km 47 near Guanabara which is west of Rio de Janeiro. On our return flight to the United States we stopped in Rio de Janeiro and visited with Dra. Dobereiner concerning her work with nitrogen fixation in grasses. We were able to collect some additional Paspalum species at the station and in the Rio area. Seed of these plants were brought with us to Miami where they were forwarded to the USDA Plant Inspection Station in Washington D. C. A total of 346 collections were made in Brazil and 216 of them were of Paspalums . SUMMARY The plant exploration and collection trip to Brazil, Paraguay and Uruguay lasted for two months. The cooperation and assistance we received from scien- tists in these countries and U. S. AID personnel was excellent. A total of 720 collections were made and these can be categorized as follows: 416 Paspalums which represents more than 50 species, 154 legumes comprising 27 genera; 117 grasses other than Paspalum species which represents 34 genera; and 33 miscellaneous collections. In addition to these approximately 30 soil samples were collected and 34 nodules samples were obtained from some of the legumes collected. A number of diverse forms of dallisgrass were found and collected. Be- fore the mode of reproduction and crossability of these plants can be deter- mined they will have to be studied cytologically and evaluated in a hybridiza- tion program. 55 PRODUCING SEED OF TILLMAN WHITE CLOVER By Pryce B. Gibson — ^ Tillman was released in October, 1965, jointly by the Agricultural Research Service, U. S. Department of Agriculture and the South Carolina Agriculture Experiment Station. In 1965 a few grams of breeder seed which is an equivalent of viable seed from each of three clonal crosses were produced in bee cages at Clemson. The few grams of breeder seed were sent to Oregon for use in a seed increase pro- gram. Reports on this venture were optomistic in 1966 and in early 1967. Later reports indicated that a series of unfortunate events resulted in near failure . The Oregon program eventually yielded enough foundation seed to plant about 5 acres. In 1969 the 5 acres produced approximately one ton of registered seed. Part of the registered seed was made available to farmers in the Carolinas. Late in 1967 because of the series of unfortunate events that occurred in Oregon, South Carolina applied for Tillman to be included in the National Foundation Seed Project. The application was approved in 1968 and a seed production program was promptly started. The N.F.S.P. soon produced adequate supplies of stock seed. Supplies of stock seed are now adequate and satisfac- tory reserves are in storage. Production of certifed seed lagged. The FCX contracted with Cal/WEST to produce seed. Thus the FCX led the way in supplying seed to farmers. This year Sawan is marketing seed and supplies are reported to be adequate. The N.F.S.P. demonstrated with Tillman as it has with cultivars of other species that it can quickly and with little risk of failure produce the stock seed of a new cultivar. 1/ Research Agronomist, ARS-USDA, Agronomy Dept., Clemson University, Clemson, S. C. 29631 56 ADVANCES IN RHIZOBIUM SPECIFICITY AND ITS SIGNIFICANCE TO FORAGE LEGUME BREEDING By Joe C. Burton — / Leguminous forage plants gather dinitrogen, (N2) when nodulated by effec- tive bacteria and need no N fertilizers. With fossil fuel dwindling and high prices of N fertilizer, interest in symbiotic nitrogen fixation has greatly expanded . Symbiotic N2 fixation is a complex interaction between three systems, the nodule bacteria, the legume host, and the environment. Maximum efficiency depends upon discreet matching of bacteria and plant for each particular en- vironment. Certain workers (2, 5, 12) attach more significance to selecting the proper strains of rhizobia; others consider the plant as the most important symbiont (7, 8, 9). Maximum symbiotic N fixation requires efficiency in both symbionts and will require the united effort of Agronomists and Microbiologists. Rhizobium Strain Selection The prime attribute in Rhizobium strain selection is effectiveness, the ability to work symbiotical ly with a particular host plant and provide suffi- cient N for maximum crop yield. N fixing ability is determined by putting the bacteris and plant together un^er favorable conditions and measuring pro- tein and yield. The new acetylene reduction technique for measuring nitrogenase activity should now make the screening process quicker and easier (_1) . While N fixing ability is essential Rhizobium strains equal in this property often differ in other qualities which are extremely important under field conditions. Rhizobium strains which are effective on a wide spectrum of host plants are much preferred over strains which are effective on only one or two hosts. Competitiveness or the ability to nodulate their host in the pre- sence of numerous other infective strains in the rhizoshpere is a highly de- sirable quality ( 3 , VI, 12) . The ability of a Rhizobium strain to survive in soil in the absence of their host is very important particularly with reseeding annual legumes. Apparently some strains of rhizobia are better equipped than others to induce nodulation and fix N? in high N soils. Such strains are ad- vantageous where leguminous crops are“grown with grass or other non- leguminous crops which may require more N fertilizer. 1/ Vice President, Research and Development, The Nitragin Company P. 0. Box 6186, Milwaukee, Wis. 53209. 57 Rhizobium - Trifolium Reactions The clovers are very important forage plants. All Trifolium species are nodulated by a single species of bacteria, Rhizobium trif olii and constitute a cross- inoc ulation group. This group is considered discreet because it contains only one plant genus. At one time, it was thought that strains of Rhizobium effective on one species such as red T. pratense L. or white T. repens L. clover would be effective on all clovers. The fallacy of this conclusion is illustrated in Figure 1. Seven Tr if ol ium species commonly grown in the U. S. were tested for ^ fixing abilities in association with 8 strains of Rhizobium trifolii and two polyvalent or composite inocula "B" and "R". The parent host and origin of strains of Rhizobium are listed in Table 1. Only one of the Rhizobium strains was effective on as many as 4 species of clover. Two strains were effective on 3 species and one was effective on only two of the clovers. Three of the strains were not highly effective on any of the 7 test plants. Nodulation was abundant in all treatments. The composite inocula were effective on a wider spectrum of host plants than the single strain cultures. Inocula "R" and "B" were effective on 6 and 5 respectively of the 7 Trifolium species. Cultivars differ in Nq fixing abilities with strains of Rhizobia Three cultivars of T. repens : Ladino, New Zealand white and Louisiana S-l were tested for N2 fixing ability in association with 9 strains of rhizobia (Figure 2) . Two of the nine strains of Rhizobium were effective on all three cultivars of T. repens . The majority of the strains were effective on only one cultivar. Strain T-85 and T-86 were ineffective onall cultivars of white clover, but were effective on T. fragiferum L. cv. Salina. The two cultivars of Strawberry Clover, Salina and Palestine varied widely in their response. Six of the 9 strains of Rhizobia were effective on Salina Clover but only one of these strains, PPl, was effective on Palestine. Several of the strains were moderately effective on Palestine Clover. Two strains of Rhizobia which were effective on Ladino Clover, S5 and S7, were completely ineffective on Strawberry Clover, (Fiqure 2). A reverse rela- tionship was noted with strains T-85 and T-86. These were effective on Salina Clover, but completely ineffective on the three cultivars of T. repens . Seven of the nine strains of R. trifolii were either effective or moderate- ly effective on Red Clover, T. pratense . Strains T-85 and T-86 were ineffective on both Red and White Clovers. Nodulation was abundant on all of the inoculated plants . Rhizobia - Plant interactions with 15 uncommon Trifolium species. Fifteen Trifolium species, from Turkey, Israel, Australia, Spain, and Morocco were tested for N2 fixing ability with6 strains or rhizobia obtained from diverse geographical areas and which were all effective on ther parent hosts, (Figure 3). The shortage of seeds and low germination prevented obtain- ing reaction with all bacter ia-plant combinations. Strain Y6, an isolate from T. ves iculosum, was effective on 14 of 14 Trifolium species. Pl7, an isolate from Red Clover, was effective on 7 of 13 58 TABLE 1. --Parent Hosts and Geographical Origin of Strains of Rhizobium trifolii referred to in this paper. Listings are alphabetical according to species name. R. trifolii Strain Parent Host Geographical Source Other Description B4 T. alexandrinum L. Unknown Hollowell 10 C6 T. ambiguum M. Bieb. Missouri, USA CCl T. burchell ianum Rhodesia Corby G14-G16 T. hirtum All California, USA K10 T. incarnatum L. Mississippi, USA K12-K13 T. incarnatum L. Alabama, USA P17 T. pratense L. Wisconsin, USA UW 203 P30 T. pratense L. Hansen 17 PPl T. purpureum California, USA T85-T86 T. purpureum California, USA S5 T. repens L. Florida, USA S7 T. repens L. Kentucky, USA T2 T. semipilosum Kenya CB526 Xll T. subterraneum L. Australia Jensen 67-3 X13 T. subterraneum Austral ia WA67 X31 T. subterraneum Australia C2480a X32 T. subterraneum Australia WU290 Zl T. subterraneum Austral ia TAl X7 T. subterraneum USDA Erdman 3DIW9 X15-X19 T. subterraneum California, USA X33 T. subterraneum California, USA Munns #1 X34 T. subterraneum California, USA Munns #3 X16-X84 T. subterraneum California, USA XXI T. usambarence Africa Norris C6771 C6 T. ambiguum Mississippi, USA Yl T. vesiculosum Wisconsin, USA Y10-Y17 T. vesiculosum Alabama, USA 59 clover species. Strain X31, a highly effective Rhizobium strain from subterra- neum clover, was effective on 7 of 13 species. The isolate C6 from Kura Clover T. ambiguum was not effective on any of 13 Trifolium species included, and failed to produce nodules on 4 of these 13 species. Rhizobium Strain T2, and isolate from T. semipilosum, one of the African species of clover was very effective on T. compactum, but completely ineffective on the other 14 clover species. It produced nodules on all but 2 of the clovers. The African Clovers are noted for their high degree of specificity and lack of response to Rhizo- bium strains which are highly effective on clovers grown in the U. S. Finally, Strain XXI isolated from T. usambarense , also an African Clover, was effective only on T. occidentale . This strain failed to produce nodules on 8 of 11 of the clover species. The diversity of reactions obtained here serves to demonstrate the com- plexity of Rhizobium - plant associations even in one of our most discreet cross-inoculation groups. It is clear that the only way to determine whether Rhizobium "A" will work effectively with Legume host "B" is to put them to- gether under conditions suitable for symbiotic N2 fixation and note the re- sults. Infectiveness vs Effectiveness in Nodule Bacteria One of the desirable qualities in rhizobia mentioned earlier was "Compet iveness" or the ability to nodulate their host grown in a soil which harbors large numbers of native or carry-over rhizobia capable of infecting it. The number of rhizobia which can be applied to seed is very small in relation to the numbers in soil following a crop of a leguminous plant of the same cross- inoculation group. When these carry-over rhizobia are ineffective on the legume to be planted, it demands the largest possible inoculum of effective rhizobia and they must have this quality called "Competitiveness" if the new crop is to thrive. The indigenous flora of the Sierra Rangelands of California consists of a number of Trifolium species with little or no forage value (_10) . This native flora of Trifolium species has resulted in a native population of R. tr if ol ii which is highly infective on Subterraneum and Rose Clover but produce in- effective or parasitic nodules. Successful establishment of Sub and Rose Clovers requires large inocula of highly competitive effective R. tr if olii strains (L2) . Selecting Rhizobium strains for "Competitiveness" The most common method of measuring "Competitiveness" is to inoculate the seed with a test strain which can be distinguished from rhizobia in the rhizosphere either culturally or serologically. The nodules on the plants are sampled and tested to determine the relative numbers of nodules produced by the inoculum strains. The two most serious difficulties with this method are: 1) It is very time consuming and 2) the technique is limited to comparison of rhizobia with different serological patterns. A Lenoard jar technique in which seed are inoculated with the effective strains and planted in sand containing an inoculum of ineffective rhizobia has worked well in selecting Rhizobium strains for Subterraneum and Rose Clover planted on the Sierra Rangelands of Northern California. New isolates of rhizobia are first tested for N2 fixing ability. The most effective Rhizobium 60 strains are then tested for competitiveness using the Leonard jar technique. After a 6-week growth period plants are harvested, dried and analyzed for total N. Strains of rhizobia differ greatly in their ability to fix N2 without com- petition from ineffective bacteria in the substrate. The majority of the strains fix larger amounts of N when planted in the sterile sand as compared to those planted in the sand containing the ineffective rhizobia (Figure 4) . However, the most effective strains as measured in sterile sand are often not the most effective when they have to compete with the rhizosphere rhizobia. In pure culture, Strain X15 was more effective than Strains X16, X17, X18, and X19, but in the competition series, X15 was inferior to these same 4 strains (Figure 4) . Rhizobium strains which prove the most competitive in the growth chamber tests are further tested under field conditions. Peat-base inocula are pre- pared and tested under field conditions. In general, strains which demonstrate good "Competitiveness" in the growth chamber also prove most effective in the field. Typical data are shown in Table 2. Strains selected for competitive- ness by the Leonard jar mathod, combined with good inoculation practices have proven very successful. TABLE 2 . - -Effect of strains of Rhizobium trifolii on Growth of Woogenellup, Subterraneum, and Hykon Rose Clovers. (Data from Dr. M. Jones, Univ. of Cal Davis. 1975) Strain of Woogenellup Hykon R. trifolii Middle Orchard Middle Orchard None 18 ai/ Millimeters/Longest Leaf 16 a 17 a 17 a G 14 38 efg 26 c 43 cde 32 e G 15 39 fg 26 c 44 de 28 bed X31 35 def 26 c 42 cd 26 b X47 40 g 27 cd 44 de 27 be X68 40 g 30 de 39 c 29 cde X84 39 fg 31 e 44 cde 27 be 1/ Values within a column followed by the same letter are not signif i- cantly different at the 0.05 level. One of the desired characteristics of rhizobia mentioned earlier was ability to survive in the soil or what some workers refer to as "saprophytic competence". This quality is particularly important with Subterraneum Clover, an annual which makes its growth in the rainy spring season, produces seed and buries them in the soil where they remain dormant during the dry summer season. The seeds germinate when the fall rains come. If the effective rhizobia do not remain viable in the soil during the hot dry summer season, little forage will be produced the following year. While no direct method has been devised to measure this quality, generally effective strains isolated from plants or fields which have been producing good Subterraneum and Rose Clovers for several years have also demonstrated good "saprophytic competence" during the 5 years these studies have been pursued. 61 Rhizobium competitiveness with Crimson and Arrowleaf Clovers A large population of infective non-nitrogen-fixing rhizobia in the soil can make it difficult to obtain effective nodulation of many of our leguminous crops. Eleven strains of Rhizobium were highly effective on Crimson Clover T. incarnatum when the inoculated seed were planted in sterile sand (Figure 5) . However, when these same effectively inoculated seeds were planted in sand containing an inoculum of ineffective rhizobia mixed into the sand, fixation was reduced by more than 507, with 8 of the 11 Rhizobium strains. Strains K12, Kl3, and YlO demonstrated good competitiveness. The others would be considered poor competitors. When these same 11 strains of R. trifolii were tested on Arrowleaf Clover, T. vesiculosum, the competitive effect was even more marked (Figure 6) . Strain K12 brought about fixation of around 9 mg per plant when the seeds were planted in sterile sand but in the presence of the ineffective inocula only 1 mg N per plant was fixed. Eight of the eleven strains were very poor competitors. Strains Yl3, Y14, and Yl7, recent isolates from field grown Arrowleaf Clover, showed a high degree of competitiveness. These are the strains that should be used under field conditions. Soil rhizobia can influence legume crop rotation The importance of selecting rhizobia which are effective on a wide spectrum of host plants was mentioned earlier. Several annual Trifolium species may be adapted to any particular geographical area. Crimson, Rose, or Subterraneum Clover mixtures might be grown in the Northwest or Southeast U. S.A. Strains of rhizobia effective on one of these clovers are often in- effective on another. Strains X33, X34, X35 , and X37 are effective on Subterraneum Clover but almost completely ineffective on Crimson and Rose Clovers, (Figure 7). Woogenellup Clover inoculated with any of these strains should grow well but it would not be wise to change to Rose or Crimson Clover the following year. On the other hand, strains X15, X19, and X31 are effective on Subterraneum, Crimson, and Rose Clovers. Use of wide spectrum strains such as these would permit growth of any one or a mixture of the 3 Trifolium species without any buildup of ineffective rhizobia in the soil. Considera- tions should be given to the rhizobia content of soils as well as levels of phosphorous, potassium and other nutrients. This discussion has been concerned exclusively with Rhizobium Trifolium interactions. The phenomena reported here occur also with Lotus sp. (2^) Medicago sp. , Vicia faba, the Mung Bean Phaseolus radiata (4) and possibly many others. The microflora of ineffective rhizobia is a very determinate factor in successful inoculation of legumes with highly efficient strains. The Host Plant as a Symbiont So far attention has been given only to the good characteristics of the Microsymbiont. Certain workers (_7, 9) have suggested that the plant is the major factor controlling N2 fixation because it is the plant which must capture the solar energy and make it available for the fixation process. There is good evidence to support this postulate in the case of grain legumes but the arguments are less convincing with the forage legumes which usually 62 have a longer growing season, and produce comparatively lower yields of small seeds, even when allowed to mature before cutting. Nonetheless, it can not be denied that the host plant is a very important factor in an effective N2 fixing association and plant geneticists will need to pay heed to ^ fixing genes carried by the host plant. Up to now the Rhizobiologist has little access to new plant development until they are ready for introduction to the public. It is then his task to find effective Rhizobium Strains for the new plant mater ial . It has generally been conceded that nitrogenase, the enzyme responsible for reduction of N2 was a product of symbiosis and that neither symbiont alone could produce it. Recent findings (6, _13) negate this idea. It has been con- vincingly demonstrated that certain strains of cowpea rhizobia can produce nitrogenase in pure culture. Further, it has been demonstrated with that these pure cultures of rhizobia fix nitrogen. The importance of this can not be assessed until more data on amounts of N2 fixed are available. Certain- ly it is still doubtful that the rhizobia alone can provide any substantial quantities of N fertilizer. We shall still have to use the leguminous host to capture the solar energy. The challenge here is to find what other factors the leguminous plant contributes in symbiotic N2 fixation. LITERATURE CITED (1) Burris, R. H. 1974. Chapter 2, Methodology _in Biology of Nitrogen Fixation (ed) Quispel . American Elsenier Pub. Co., New York. (2) Burton, Joe C. 1964. The Rhizobium- Legume Association. JLn Microbiology and Soil Fertility Proc. Biology Colloquim, Oregon State Univ. Press, Corvallis, Ore. (3) . 1970. Determinants in Rhizobia-Legume Association. Abstracts, X International Congress for Microbiol, p. 221. (4) . 1975. Pragmatic Aspects of the Rhizobium leguminous plant Association (Meeting Abstract) . International Symposium on N2 Fixation, Pullman, Washington. June 1974. In Press. (5) . 1972. Nodulation and Symbiotic Nitrogen Fixation. Alfalfa Science & Tech. Mono. 15, Amer. Sco. Agron. 11:229-245. (6) Child, J. J. 1975. Nitrogen Fixation by a Rhizdbium sp. in Association with Non- leguminous Plant Cell Culture. Nature 253: 350-351. (7) Hardy, R. W. F., and Havelka, U. D. 1975. Nitrogen Fixation Research. A Key to World Food. Science 188: 633-643. (8) Havelka, U. D., and Hardy, R. W. F. 1975. Legume N2 Fixation as a Problem in Carbon Nutrition. (Meeting Abstract) International Symposium on N2 Fixation. Pullman, Washington. June 1974, _In Press . (9) Holl, A. G., and La Rue, T. A. G. 1975. Genetics of Legume Plant Hosts. (Meeting Abstract) International Symposium on N2 Fixation. Pullman, Washington. June 1974. I_n Press . 63 (10) Holland, A. A. 1970. Competition between soil- and seed-borne Rhizobium trifolii in nodulation of introduced Trifolium subterraneum. Plant and Soil 32: 293-302. (11) Lohandera, C. A., and Vincent, J. M. 1975. Competition between an introduced strain and native Uruguayan strain of Rhizobium trifolii. Plant and Soil 42: 327-347. (12) Murphy, A. H. , Jones, M. B., Clawson, J. W. , and Street, J. E. 1973. Management of Clovers on California Annual Grassland. Cir. 564 - Cal. Agr. Sta. 19 pp. (13) Scowcroft, W. R. , and Gibson, A. H. 1975. Nitrogen Fixation by Rhizobium Associated with Tobacco and Cowpea Cell Cultures. Nature 253: 351-352. 64 Figure Legends Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Reactions of 7 species of Trifolium to inoculation with 8 strains of R. trif olii and 2 multiple strain inocula "B" and "R" . Reactions are arbitrarily classed as effective, moderately effective, or ineffective based on total N-content. When plants contained 75 to 1007o as much N as the best inoculation treatments and plants were vigorous and colored deep green, the reactions were classed effective. When plants contained 50 to 757, N content of best treat- ment the reaction was designated moderately effective. Plants with less than 507, of the best total N content were classed ineffective. Reactions of 3 cultivars of T. repens , 2 cultivars of T. fragiferum and 1 cultivar of T. pratense to inoculation with 9 different cultures of R. trif olii . Response of 15 Trifolium species from Australia, Turkey, Spain, Morocco and Israel to 6 diverse strains of R. trif olii. N2 fixation by T. subterraneum cv. Woogenellup to 8 strains of R. tr if ol ii isolated from surviving thrifty subterraneum clover plants from poor fields in Northern California. Inoculated seed were planted in sterile sand and in sand containing an inoculum of ineffective rhizobia from the same area. N2 fixation by T. incarnatum to inoculation with 11 different strains of R. trif olii in sterile sand and in sand containing an inoculum of ineffective rhizobia. fixation by T. vesiculosum cv. Yuchi inoculated with 11 strains of R. trif olii . Effectively inoculated seeds were planted in sterile sand and in sand containing an inoculum of ineffective rhizobia . N2 fixation by T. incarnatum, T. subterraneum and T. hirtum to inoculation with 7 strains of R. trifolii. 65 Host Plant (Clovers) Rhizobia Strains Berseem ■■■□□□□■an Crimson Rose Subterraneandl II 1 MB HIM BIB Red □□■□□□□□HD While □ □□■□□□□HIIS Strawberry ^Effective Jj|| Modera+ely effective | | Ineffective Figure 1 HOST PLANT Trifolium repens Ladino N.Z. White La. S-l STRAINS OF RHIZOBIA o — to co in N n n oIon-opaD COIOq_Q_Q_OX(— H1- bhhh^bbdd □!□□□!!□□ Trifolium fraqiferum Salina □ □E3H8HMBM Palestine □□lllDIli Trifolium pratense Kenland HBBB^BBIHn §§ Effective F7! Moderately Effective O Ineffective Figure 2 STRAINS OF RHIZOBIA IBIFOLIUM SR Y6 PI7 X3I C6 T2 XXI T. affine m m E n fi 0 X berytheum IBlli 0 X bocconi HDDISIH 0 I boissieri X compactum X dasyurum X globosum I meduseum I mutabile X occidentale X pallidum X philisticum X physodes □ □ □ ■ □ no 0 0 0 □ II □ X vavilovii HI m 0 0 T. vernum Hi 0 0 0 HI Effective fi| Ineffective Figure 3 [0]No nodules QNo plants Trifolium incornatum STRAIN OF RHIZOBIA HI Effective only g§| Ineffective in sand Figure 5 66 Trifolium vesiculosum ( Yuchi ) ID Effective only §1 Ineffective in sand Figure 6 67 INOCULATION TECHNIQUES FOR TEMPERATE FORAGE LEGUMES AND THEIR AFFECT ON RHIZOBIUM SURVIVAL By Richard W. Weaver 1/ ABSTRACT The purpose of this presentation is to aquaint the reader with some of the history of the inoeulum industry as it pertains to development of better inocula- tion techniques. Discussion and data are largely limited to inoculation of forage legumes. However, the concepts on objectives of inoculation and the need for inoculation are valid for all legumes. Data is presented illustrat- ing the importance of using an adhesive in attaching the inoculum to seed and in pelleting inoculated clover seed with lime when planting in acidic soils. Inoculum placement is evaluated because of the limited mobility of rhizobia in soil and the opportunity this offers in restricting nodulation to that portion of the soil environment that is most favorable for nitrogen fixation. INTRODUCTION Rhizobia capable of forming an effective symbiosis with clovers grown on soils of the Southern region are not normally present in adequate numbers for early, effective nodulation. They must be added to the soil when the legume is planted if effective nodulation is to occur. In Texas, Abon Persion clover, Louisiana S-l white clover, Meechee arrowleaf clover, and subterranean clover must be inoculated with a commercial inoculum at planting to achieve effective nodulation (personal observations) . Without the proper rhizobia to form abundant nodulation on the plant efficient dry matter production is not possible. The objective of inoculation is to provide adequate numbers of effective rhizobia to nodulate the legume and supply the nitrogen needed for efficient production. The Australians suggest a minimal inoculum level of 300 per seed when the seed is sown under ideal conditions for survival of the rhizobia and no com- petitive rhizobia are present in the soil (16) . When ineffective rhizobia are present or soil conditions are not favorable for survival of rhizobia several thousand effective rhizobia must be added per seed to insure effective nodulation (24, 2_7, 46, 47, 48) . Unfortunately, many of the soils in the Southern region have ineffective rhizobia present and must be thoroughly in- oculated using the best inoculation practices at planting if they are to efficiently produce clover Q29, 45Q . 1 / Assistant Professor, soil microbiology, Department of Soil & Crop Sciences, The Texas Agricultural Experiment Station, College Station. 63 Inoculum Carrier The earliest method of inoculating legumes was accomplished by spreading soil from an area that grew well nodulated plants of the appropriate species to the field that was to be inoculated. Soil transfer as a method for inocu- lating legumes was successful when enough soil was transferred to supply ade- quate numbers of the needed rhizobia (_18) . Obviously, it was difficult to know how much soil to use because soils vary by at least five orders of mag- nitude in the numbers of rhizobia present (2_7) . This means that a few pounds of one soil would be a suitable inoculum but several thousand pounds of another soil would be required. Normally several hundred to a few thousand pounds of soil were used to inoculate each acre of the field being planted (18). Besides difficulties in transferring soil there were the disadvantages of transferring weeds and plant disease organisms with the soil from field to field . Shortly after rhizobia were isolated from nodules in 1888 by Beijerinck pure cultures of rhizobia were prepared commercially for use by farmers. The first cultures were produced in 1895 and consisted of organisms grown on a gelatin slant containing required nutrients. The farmer removed the rhizobia from the slant and applied them to his seed in a water suspension. This technique did not have the disadvantages of the soil transfer method but did not gain wide acceptance because results were inconsistent and sometimes the crop yields were less than that achieved by the soil transfer method (L8) . A new pure culture technique of inoculating legumes was developed and marketed in 1902 (_18) . The rhizobia were cultured and distributed to the farmer in a liquid medium. Unfortunately, this method was also inferior to the soil transfer method in providing viable rhizobia to the germinating seed- ling. Commerical cultures continued to compete with soil transfer methods until the early 1940's (31) . In the late 1930 's the present inoculum carrier, peat, was coming into use (30) . It soon replaced the soil transfer method and by early 1940 's was the principal inoculum carrier being used (31_) . Peat provided a suitable environment for relat ively 1 ongterm survival of rhizobia (Figure 1 ) and was a suitable form of inoculum for unskilled workers to use. Presently, a peat base inoculum is the only one recommended in Australia and the principal one used in the U. S. (8^, 43) . Even with the peat carrier, precautions against excessive heating (Figure 1) and drying of the inoculum must be made (_7, 9). The latter is accomplished by adjusting the moisture content of the peat to the proper level and sealing the peat in a plastic bag that provides some aeration without moisture loss (_9, 43) . The moisture content of the peat is critical in survival of the rhi- zobia as is selection and modification of the peat before the inoculum is mixed with it (35, 36, 37, 39). Long term storage of viable rhizobia has been accomplished by freeze drying techniques (34) . The principal disadvantage of this technique was the high death rate of freeze dried rhizobia on seed (43) . Seed inoculated with 10,000 rhizobia per seed from a freeze dried culture only had 30 viable rhi- zobia 1 day after inoculation and none after 7 days whereas seed inoculated with a peat inoculum had ten times more surviving at 1 day and 25 per seed at 7 days (JL5) . Because of this poor survival on seed, freeze dried techniques have been used little in recent years. 69 Inoculum Adhesive It was recognized early that rhizobia move only short distances in soil and must be placed in the vicinity of the plant root (_18) . The early inocula- tion method of soil transfer revealed this when it was shown that several hundred pounds of inoculum applied to the soil was no more effective than applying a fraction of a pound to the seed (18) . The soil was applied to the seed as a slurry and upon drying would stick to the seed. The use of an adhesive with inoculum not only provides for better distri- bution of the inoculum on the seeds but greatly increases the survival of the rhizobia (Figures 2 and 3) . Many adhesives have successfully been used to in- crease the survival of rhizobia on seed (4, 14- , 15 , 16 , 21 , 44). They include, in increasing order of protection afforded the rhizobia, glucose, cellobiose, lactose, sucrose, raffinose, sorbitol, maltose, dextrine, hydroxypropyl cellu- lose, carboxymethyl cellulose, methyl cellulose, and gum arabic. One problem with using the better adhesives, has been their lack of availability at the retail store. With greater farmer awareness on the usefulness of this material it can be supplied with the inoculum by the inoculum manufactures. In fact at least one inoculum manufacturer has had an adhesive on the market for years (THE NITRAGIN COMPANY, Milwaukee, Wise.). The only adhesives readily available from most local retail stores are sucrose and milk. A 257, water solution of sucrose used as an adhesive in inoculating alfalfa seed with a peat inoculum decreased the death rate of rhizobia by a factor of 800 after only 2 weeks storage at 24C (9) . No data was available on the protection actually afforded by milk. The adhesives extend the survival of rhizobia by reducing the harmful effects of desiccat ion (44) and protect the rhizobia from substances on seed coats that are toxic (2^, 40, 44) . Glass beads and seeds inoculated with a broth inoculum and stored at 24 C with and without adhesives illustrate the importance of the adhesive in extending the survival of the rhizobia (Figure 3). Inoculum Pellet When rhizobia are inoculated into soil their chemical and physical envi- ronment is drastically changed. One of the most important changes that may occur is pH. Rhizobia capable of nodulating most temperate forage legumes are very sensitive to a soil pH of 5.5 or below (42) . In fact they may die before nodulating a host in soils of pH 5 or below (39 , 42) . To alleviate this pro- blem a technique was developed to coat the legume seed with a neutralizing agent to increase the pH in the vicinity of the seed (32) . The principal pelleting material used was fine particle CaCC^. This agricultural lime must not be con- fused with hydrated lime or slak lime because these materials are very caustic and will kill the rhizobia and possibly the seed. Pelleting clover seeds with lime is a popular practice in Australia (4, 6, 16, 36) and has been used in the U. S. with good results (24, 26, 29, 45) ~~ Pelleted seed planted into soil of pH 4.4 had more than 100 times as many viable rhizobia as nonpelleted seed (14). Pelleting materials other than CaCO^ have been used but were not found to be superior (4, _16, 23) . A detailed description of the pelleting procedure using CaCO^ has been provided in several publications (1, 26_, 36, 43) , but for the convenience of the reader a description is provided in Appendix A. 70 Soil Conditions The physical, chemical, and microbiological condition of the soil have large effects on whether inoculation is successful or not. Two physical conditions that affect the survival of the rhizobia are moisture and tempera- ture. The chemical conditions are soil pH, and the mineral makeup of the soil. Many actinomycetes , fungi and other microorganisms are present in the soil that are antagonistic to the rhizobia. A short discussion on each of the topics on soil conditions as related to survival of rhizobia follows. Soil pH will not be discussed because it was covered in the section on pelleting. Soil moisture has both an indirect and a direct effect on the success of inoculation. If soil is dry at planting the seed may not germinate for several days or even weeks. With such conditions the rhizobia must survive in the soil for an extended period of time. Soil moisture content has a direct effect on the survival of the rhizobia (42) . The population of clover rhizobia decreased 90% when exposed to 60% relative humidity for 1 day but did not decrease when humidity was maintained at 100%. This may not be as drastic as it might seem because the relative humidty in soil at the permanent wilting percentage of plants is near 100%. However, if the rhizobia are on seed sown at the surface of the soil, desiccation could have a strong effect on their survival. Soil moisture content affects the movement of rhizobia. Rhizobia in soils that are at field capacity or drier do not move more than a few milli- meters per day (200 . Seedlings from seeds growing 3 cm. to the side of the inoculum may not be nodulated (_10) . The inoculum must be located next to the seed or where a plant root will grow into it (32) . High temperatures are very detrimental to rhizobia. In laboratory media rhizobia do not generally survive temperatures above 43C (3) . Bare surface soil temperatures in Texas exceed 65 C (personal communication M. E. Blood- worth) during the warmest months but are usually less than 40 C at 5 cm soil depth (JJ?, 50) . Fortunately the clay in soil increases the soil temperature at which rhizobia can survive (33_, 49) . Numbers of viable rhizobia decreased 10 fold in some soils after raising soil temperature from 30 C to 50 C for 5 hours but populations in other soils did not decrease (22) • The investigators determined that the clays illite, montmor illonite , and haematite provided pro- tection to the rhizobia but kaolinite did not. Three 5 hour exposures of 50 C in 3 days reduced the population of rhizobia from 100,000 per g of a sandy soil to less than 1 per g. Mixing montmor il Ionite into the soil increased the survival of the rhizobia and more than 1,000 per g were viable after the same treatment . For any organism to survive in soil it must be able to establish itself a niche where it is competitive with other organisms for energy material (17) and has a faster growth rate than the rate at which it is parasitized or poisoned by other organisms. In sterile soil rhizobia survived in high num- bers but in nonsterile soils their numbers declined (_10) . Soil contains viruses, bdellovibrios , and protozoans that actively prey on bacteria. How- ever, rhizobia would not likely be eliminated from soil by these parasites alone (12_, 28) . Numerous fungi and actinomycetes that were isolated from soil produced antibioties that stronly inhibited the growth of rhizobia in labora- tory culture (_10, 11 , 41) and have been implicated in nodulation failures in the field (22, 25) . The real significance of antibiotic producing organisms in limiting populations of rhizobia in soil has not been established although water extracts of soils contained substances toxic to rhizobia (25) . 71 Soil moisture and temperature conditions that are optimum for early germination and emergence of clovers are satisfactory for survival of rhizobia. Seedlings from seed planted into dry soil or sown onto the surface of dry soil may not be promptly nodulated because the number of viable rhizobia surviving on or near the seed may be very low (2_1) . The surface of bare soil in the Southern region is hot enough to suspect rapid death of rhizobia on exposed seed. Sod seeding or incorporating the seed into the soil could reduce the temperture in the immediate environment of the rhizobia by 10 C or more. Because both soil temperature and soil moisture effect the survival of rhizobia and the rate of nitrogen fixation inoculum placement may be a way of maximizing nitrogen fixation and plant growth. Inoculum placed beneath the seed would form nodules on roots near the location of inoculum placement (^8) . Roots formed above the inoculum would not nodulate (13) . Soil temperature and soil moisture will be different at various soil depths. Placement of in- oculum in zones most favorable for nitrogen fixation would insure that soil environmental conditions would be the best that the particular soil could provide. Inoculum applied separately from the seed but precisely in the root region would provide for a way of planting concurrently with inoculation which should increase the viable rhizobia population in the soil. CONCLUDING REMARKS There has been much information published on inoculation techniques and their effect on nodulation and survival of rhizobia on seed and in soil. This information is important for an efficient legume program. We must use effective inoculation techniques if forage legumes are to succeed in our region. The data discussed in this presentation has shown that inoculation of seed should if possible be performed at the time of planting. Under good storage conditions of 21 C and using the best inoculation procedures viable rhizobia on seed stored for 1 week would likely decrease by 50% to 997,. When inoculating seed an adhesive should be used, it increases the survival of rhizobia on the seed, extends their survival in the soil and aids in obtaining uniform distri- bution of inoculum. Inoculating one seed with a double rate of inoculant and not inoculating another is not very effective because rhizobia do not actively move in soil and only one seedling would be promptly nodulated. Gum arabic is the best adhesive that has been tested on extending the survival of rhizobia on seed but when it or a commerical adhesive is not available a 25% solution of sucrose is a fairly good adhesive and provides some protection to the rhizo- bia . Seed pelleting with CaCO^ is a good practice especially when the seed is sown in acidic soils. When seeding into acid soils pelleting is needed to allow enough rhizobia to survive to promptly nodulate the plant. There is still much to be gained from continued efforts on development of better inoculation methods. Farmers would much perfer effective preinoculation of seed so that they need not be concerned about wetting seed and applying the inoculum when they are preparing for plant ing . Perhaps the development of gran- ular forms of inoculum that are being marketed for soybean and peanut inocula- tion have a potential for use on temperate legumes. Such an inoculum would provide a way of inoculating clover or alfalfa the second year after planting and would provide inoculum pockets in the soil that could nodulate the stolon- iferous roots of clover as they developed during the growing season. It is 72 not enough to merely develop an inoculation technique that provides for viable rhizobia (.5) but the rhizobia must be located such that they come into contact with the root system. Appendix A - Pelleting legume seed Adhesive - Completely dissolve 100 gm of gum arabic, that does not contain a preservative, in 230 ml water. The gum arabic should be light in color and not acidic. Inoculum - A high quality peat inoculum should be used at the rate of 70 g per 7 Kg of small seed (white clover) or 14 Kg of medium seed (subterranean clover). Pellet - The pellet is formed by coating the seed with finely ground CaC03 . It should pass a 30 mesh sieve. Pelleting with ordinary agricultural lime may not be successful because of its larger particle size. Plasterer's whiting is a good source of fine textured lime. Do not use slak lime because it is Ca (OH) 2 and would kill the rhizobia. Procedure - Mix the dissolved gum arabic with the inoculum and pour the slurry onto the seed. Mix the seed to obtain thorough distribution of the inoculum. Add all at once 3.4 Kg CaCO^ and mix rapidly until all seeds are evenly coat- ed. This should require 1 or 2 minutes. Too short a time will leave free lime and poorly coated seed but too much mixing may result in cracking and flaking of the pellet on drying. Let the seed dry for a few hours in a cool location before planting. LITERATURE CITED 1. Bergersen, F. J., Brockwell, J., and Thompson, J. A. 1958. Clover seed pelleted with bentonite and organic material as an aid to inoculation with nodule bacteria. J. Aust. Inst. Agric. Sci. 24: 158-160. 2. Bowen, G. D. 1961. The toxicity of legume seed diffusates toward rhizobia and other bacteria. Plant Soil XI: 155-165. 3. Bowen, G. D., and Kennedy, Margaret M. 1959. Effect of high soil temperatures on Rhizobium spp. Qd. J. Agric. Sci. 16: 177-197. 4. Brockwell, J. 1962. Studies on seed pelleting as an aid to legume seed inoculation. I. Coating materials, adhesives and methods of inoculation. Aust. J. Agr. Res. 13: 638-649. 5. Brockwell, J., and Hely, F. A. 1962. Relationship between viability and availability of Rhizobium trif olii introduced into seeds of Trifolium subterraneum L. by inhibition and pressure. Aust. J. Agric. Res. 13: 1041-1053. 6. Brockwell, J. and Whalley, R. D. B. 1962. Incorporation of peat inoculant in seed pellets for inoculation of medicago tr ibuloides Desr sown into dry soil. Aust. J. Sci. 24: 458-459. 73 7. Burton, J. A. 1964. The rhizobium- legume association. Tn Gilmour, C. M. and Allen, 0. N. (eds) , Microbiology and Soil Fertility, pp. 107-134. Oregon State University Press, Corvallis. 8. Burton, J. C. 1967. Rhizobium culture and use. In Peppier, Henry J., Microbial Technology, pp. 1-33. Reinhold Publishing Corporation, New York. 9. Burton, J. C. 1975. Methods of inoculating seeds and their effect on survival of rhizo bia. I_n Nutman, P. S. (ed.) Symbiotic Nitrogen Fixation in Plants pp. 175-189. Aberdeen University Press, Aberdeen. 10. Chatel, D. L., Greenwood, R. M. , and Parker, C. A. 1968. Saprophytic competence as an important character in the selection of rhizobium for inoculation. 9th. Inter. Congress Soil Sci. II: 65-98. 11. Damirgi, S. M. and Johnson, H. W. 1966. Effect of soil actinomycetes on strains of R. japonicum. Agron. J. 58: 223-224. 12. Danso, S. K. A., and Alexander, J. 1975. Regulation of predation by prey density: The protozoan-Rhizobium relationship. App . Micro. 29: 515-521. 13. Dart, P. J., and Pate, J. S. 1959. Nodulation studies in legumes. III. The effects of delaying inoculation on the seedling symbiosis of barrel medic, Medicago tr ibuoloides Desr. Aust. J. Biol. Sci. 12: 427-444. 14. Date, R. A. 1968. Rhizobial survival on the inoculated legume seed. 9th. Inter. Cong. Soil Sci. Trans. II: 75-83. 15. Date, R. A. 1970. Microbiological problems in the inoculation and nodulation of legumes. Plant Soil 32: 703-725. 16. Date, R. A., Batthyany, C. and Jaureche. 1965. Survival of rhizobia in inoculated and pelleted seed. IX Inter. Grassland Cong. 1: 263-269. 17. Dixon, D. D. 1969. Rhizobia (with particular reference to relationship with host plants). Ann. Rev. Mico. 23: 137-158. 18. Fred, Edwin Broun, Baldwin, Ira Lawrence, McCoy, Elizabeth. 1932. Root nodule bacteria and leguminous plants. Univ. Wise. Studies Sci. 5. 343 pp. 19. Fluker, B. J. 1958. Soil temperatures. Soil Sci. 86: 35-46. 20. Handi, Y. A. 1971. Soil-water tension and the movement of rhizobia. Soil Biol. Biochem. 3: 121-126. 21. Hely, F. W. 1965. Survival studies with Rhizobium trifolii on seed of Trifolium incarnatum L. inoculated for aerial sowing. Aust. J. Agric. Res. 16: 575-589. 22. Hely, F. W. , Bergersen, E. J., and Brockwell, J. 1957. Microbial antagonism in the rhizosphere as a factor in the failure of subterranean clover. Aust. J. Agric. Res. 8: 24-44. 74 23. Herridge, D. F . , and Roughley, R. J. 1974. Survival of some slow-growing rhizobium on inoculated legume seed. Plant Soil. 40: 441-444. 24. Holland, A. A. 1970. Competition between soil and seed-borne Rhizobium trif olii in nodulation of introduced Trifolium subterranean . Plant Soil 32: 293-302. 25. Holland, A. A., and Parker, C. A. 1966. Studies on microbial antagonism in the establishment of clover pasture II. The effect of saprophytic soil fungi upon Rhizobium tr if ol ii and the growth of subterranean clover. Plant Soil 25: 329-340. 26. Holland, A. A., Street, J. E., and Williams, W. A. 1969. Range-legume inoculation and nitrogen fixation by root-nodule bacteria. California Agr . Expt . Sta. Bull. 842. 27. Ireland, J. A., and Vincent, J. M. 1968. A quantitative study of competition for nodule formation. 9th Inter. Cong. Soil Sci. Trans. II: 85-93. 28. Keya, S. 0. and Alexander, M. 1975. Regulation of parasitism by host density: The Bdel lovibr io- Rhizobium interrelationship. Soil Biol. Biochem. 7: 189-194. 29. Knight, W. E. 1974. Response of four trifolium species to inoculum and molybdenum on an acid soil in Mississippi. Agron. Abst. 1974. 30. Leonard, Lewis T. 1937. Nitrogen fixing bacteria and legumes. USDA Farmer's Bulletin 1784. 31. Leonard, R. T. 1943. Method of testing legume bacteria cultures and results of tests of commercial inoculants in 1943. USDA Circular 703. 32. Loneragan, J. F., Meyer, D., Fawcett, R. G., and Anderson, A. J. 1955. Lime pelleted clover seeds for nodulation on acid soils. J. Aust. Inst. Agr. Sci. 21: 264-265. 33. Marshall, K. C. 1964. Survival of root nodule bacteria in dry soils exposed to high tem- peratures. Aust. J. Agric. Res. 15: 273-281. 34. McLeod, R. W. , and Roughley, R. S. 1961. Freeze-dried cultures as commercial legume inoculants. Aust. J. Expt. Agric. An. Husb. 1: 29-33. 35. Newbould, F. H. S. 1951. Studies on humus type legume inoculants I. Growth and survival in storage. Scientific Agric. 31: 463-270. 36. Roughley, R. J. 1970. The preparation and use of legume seed inoculants. Plant Soil 32: 675-701. 37. Roughley, R. J., and Vincent, J. M. 1967. Growth and survival of Rhizobium spp. in peat culture. J. Appl. Bact. 30: 362-376. 38. Schiffman, J., and Alper, Y. 1968. Effects of rhizobium- inoculum placement on peanut inoculation. Expl. Agric. 4: 203-207. 39. Steinborn, Julia, and Roughley, R. J. 1974. Sodium chloride as a cause of low numbers of Rhizobium in legume inoculants. J. App. Bact. 37: 93-99. 75 40. Thompson, J. A. 1960. Inhibition of nodule bacteria by an antibiotic from legume seed coats. Nature 187: 619-620. 41. Thornton, G. D., Alencar, J. D., and Smith, F. B. 1949. Some effects of Streptomyces albus and Penicillium species on Rhizobium melilotii. Soil Sc. Soc. Amer . Proc. 14: 188-191. 42. Vincent, J. M. 1958. Survival of the root nodule bacteria. In Hallsworth, E. G. Nutrition of the Legumes, pp. 108-133. Academic Press, Inc. New York. 43. Vincent, J. M. 1970. The production, control and use of legume inoculants. Iri a Manual for the Study of Root Nodule Bacteria. pp. 113-131. IBP Handbook No. 15. Blackwell Scientific Publications, Melbourne, Austral ia . 44. Vincent, J. M. , Thompson, J. A., and Donovan, 0. Kathleen. 1962. Death of root nodule bacteria on drying. Aust. J. Agr. Res. 13: 258-270. 45. Wade, R. H. , Hoveland, and Hiltbold, A. E. 1972. Inoculum rate and pelleting of arrowleaf clover seed. Agron. J. 64: 481-483. 46. Weaver, R. W., and Frederick, L. R. 1974. Effect of inoculum rate on competitive nodulation of Glycine max L. Merrill. I. Greenhouse studies Agron. J. 66: 229-232. 47. Weaver, R. W. , and Frederick, L. R. 1974. Effect of inoculum rate on competitive nodulation of Glycine max L. Merrill. II. Field studies. Agron. J. 66: 232-236. 48. Weber, D. F., and Leffet, G. E. 1966. Relation of rhizobia to alfalfa sickness in eastern Washington. U. S. Dept, of Agr. ARS Bulletin 41: 1-16. 49. Wilkins, Jean. 1966. The effects of high temperature on certain root-nodule bacteria. Aust. J. Agric. Res. 18: 299-304. 50. White, A. W. , Giddens, J. E., and Morris, H. D. 1959. The effect of sawdust on crop growth and physical and biological properties of Cecil soil. Soil Sci. Soc. Amer. Proc. 23: 365-368. 76 Figure Legends Figure 1. Figure 2. Figure 3. The survival of Rhizobium mel iloti in peat stored at different temperatures in moisture proof containers. (J. C. Burton, Unpublished Data) . The survival of Rhizobium trif ol ii on subterranean clover seeds inoculated with a peat inoculum slurry containing gum arabic, methyl cellulose or only water (15) . The survival of Rhizobium trifolii on subterranean clover seeds and glass beads inoculated with a broth inoculum containing gum arabic, maltose, or only water (44) . 77 Log Rhizobia/Sample Log Rh izobia/Inoculant Figure 1 'O 0) (1) C/3 CO 43 O N s oo 5 Time (days) Figure 2 Storage Time Hours Figure 3 78 DIGITARIA GENOTYPES EVALUATED IN BRAZIL FOR NITROGENASE ACTIVITY, YIELD AND IVOMD , , , 1/ By Stanley C. Schank — ABSTRACT Twenty-six digitgrass breeding lines were compared with four commercial cultivars of digitgrass and bermudagrass to determine possible dinitrogen fixation, nitrogen content, In Vitro organic matter digestibility (IVOMD), and yield. Commerical lines tested were 'Pangola', 'Transvala' and 'Slender- stern' digitgrass, and ' Coastcross- 1 ' bermudagrass. Harvests were made every 28 days during 1974 at Km47, EMBRAPA, near Rio de Janeiro. During the year, accumulative dry matter (oven-dryed) of the lowest yielding line was 16,711 kg/ha/yr and the highest line yielded over 30,000 kg/ha/yr. Commercially available cultivars were intermediate in production, and not significantly different from each other at the 0.05 level. Seven of the breeding lines of digitgrass had yields surpassing Transvala. IVOMD data revealed that Transvala, and Slenderstem were significantly higher in digestibility than Coastcross- 1 . Pangola, with 61.97> IVOMD was not significantly different from Coastcross-1 (60.67o IVOMD). Four of the genetic lines were statistically superior in IVOMD with over 677o digestibility. Nitrogenase activity by acetylene reduction, a measure of the dinitrogen fixed on roots was monitered, with rates of over 500 g^/ha/day possible under favorable conditions. Nitro- gen content of soil and plant material harvested from each plot was also monitered during the year. INTRODUCTION AND REVIEW OF RECENT LITERATURE Biological nitrogen fixation has become one of the most exciting areas of agricultural research (_H, 12 , 13) . Dobereiner and coworkers in Brazil ( 6 , 7_, ,8> 9) have identified the capacity of organisms in the rhizosphere of tropical grasses to fix considerable quantities of N2 under certain conditions. Although this was first called non-symbiotic nitrogen fixation (in grasses) to distinguish it from the well known symbiotic relationship in the legumes, the evidence is accumulating that it is indeed an associative symbiosis, and more recent reports (4, _5> .10 > _15) have reflected the change in terminology, calling it a symbiotic relationship in grasses also. With recent evidence that another C4 grass, corn, is also a fixer of nitrogen (3), additional impetus has been given to obtain data on methods to maximize the grass- bacterial association. 1/ Agronomist, University of Florida, Gainesville, Florida 32611. 79 Day et al (_5) state that since some tropical grasses have the potential to fix large amounts of nitrogen, plant breeders working in the humid tropics may well be able to promote this characteristic. Bulow and Dobereiner (3) likewise feel that N2-fixation in grasses may be increased by plant breeding, citing significant differences in fixation between Paspalum notatum and Pennisetum purpureum cultivars. They also reported the mean nitrogenase activity of the best line of corn corresponds to a daily fixation of 2.4 kg ^/ha/day, whereas the nitrogenase activity in the original cultivar only attained 0.1 kg/ha/day. The potential nitrogenase activity in maize roots approaches that of soybeans (30 . Strains of Spirillum isolated Digitar ia and corn also have recently been studied and compared ( 14) . Material and Methods Twenty-six digitgrass breeding lines were introduced into Brazil, along with four commercial cultivars of digitgrass and bermudagrass , in January 1973. I increased these introductions and established a replicated trial at the Km 47 location in Brazil during the Spring of 1973 (October) . After establish- ment, harvests were made every 28 days during 1974, for a total of 13 harvests. Dry matter yields were calculated on a gram per square meter per day basis, and ground samples were mailed to the Forage Evaluation Laboratory, Agronomy Department, University of Florida for analysis of In Vitro organic matter digestibility, and for nitrogen content using the Technicon auto analyzer. Soil analyses for nitrogen and other elements were completed in Brazil. Detailed methods used for nitrogenase determinations have been reported (j., 5) . Basically, samples of roots were collected in the afternoon from field grown plants, and placed in 60 ml serum bottles. The roots were dug with a hoe, dipped immediately into distilled water to prevent drying, and then were cut from the crown of the plant and placed inside the bottle. The bottles were evacuated 3 times and the atmosphere replaced by 57, O2 in N2, and pre- incubated overnight at room temperature. C2H2 (107, by volume) was injected in the morning and production was measured three hours later by gas chromatography (2) . RESULTS Accumulative dry matter yields for all thirty genetic lines in the test are presented in tabular form, ranking the highest yielding line first (Table 1) . Statistical analysis (Duncan's Multiple Range Test 0.05 level) showed that lines 6 and 21 were significantly better than Transvala, and all lines lower in yield than Transvala. Line # 4 and all lines above it in yield were signif- icantly better than # 16, all lines above # 27 were significantly better in yield than # 10. More than 400 samples were taken during the year for nitrogenase analysis from an adjacent Transvala plot, and these data are plotted in Fig. 1. Yield of the cultivar Transvala is given in Fig. 2, and rainfall data for the compar- ative 28 day periods is presented in Fig. 3. Yield comparisons between Pangola and Transvala are given for each of the 13 dates of cut in Fig. 4. IVOMD data comparisons during the entire year are also presented graphically for Pangola and Transvala in Fig. 5. All thirty cultivars were sampled for nitrogenase activity in January 1974 (mid- summer) , and in March 1974 (180 samples each date). These data are 80 TABLE 1 . --Accumulative dry matter yields for thirty genetic lines of digitgrass and bermudagrass in Brazil. Note: Species identity is given in Table 2. 200 kg/ha of N in ammonium nitrate fertilizer added to plots during experiment. 4J •i— 1 CO o o 1 1 o CO -d o o O 1 | O MO 1 1 o 1 1 o 1 o o 1 1 o o 1 O 1 1 1 o o 1 1 o rH CO o 1 1 o O | 1 1 1 1 00 CM 1 1 <1* o 1 oo 1 1 1 CO MO 1 1 00 d 00 r— 1 CO 1— 1 1 1 r—1 t— 1 1 1 1 1 1 t 1 1—1 CM 1 1—1 1 1 1 CM m 1 8 CM S •H X o'-* m r- MO 00 1 1 1 — 1 m 1 1 O' 1 1 00 1 O' r*. 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X) o 1—1 O' 00 m 00 o <± CM <)■ CM co o co i—i vD m Ob Ml o M S MO CM C'- CM 1—1 CM CM m CM CO oo i — i t—1 CM CM CM i — i CM cn 1—1 T—l r—1 CM CM O' T—1 T—1 T—l t—1 81 presented as Table 2, along with subsequent readings for nitrogenase samples made from core samples as described already (_1) . Although trends can be noticed in high and low fixing Digitar ias , the variations within replications was so great that statistical analysis of the data was not attempted. However, it appears that genetic differences exist between lines of digitgrass in nitrogenase activity, and a more detailed study should be accomplished using these lines and others. TABLE 2 . --Nitrogenase activity in thirty cultivars of digitgrass and bermuda- grass grown in Brazil. Both root samples and core samples were used. Data is expressed in n moles C2H^/g/root/hr . Identity No. Species designation Root Jan. '74 Samples Mar . ' 74 Core Sample 1. Digitaria decumbens cv. 'Pangola' 6 13 880.6 2. Digitaria decumbens cv. 'Transvala' 59 14 485.5 3. Digitaria sp. cv. ' Slenderstem' 34 57 975.0 4. Digitaria milaniiana Fl 299 12 27 5. Digitaria sp. unknown origin 21 9 425.6 6. D. umfolozi x D. umfolozi 0 60 237.7 7. D. umfolozi x D. milaniiana 1 8 264.9 8. D. pentzii x D. pentzii 17 18 279.2 9. D. umfolozi x D. milaniiana 1 6 10. D. valida x D. milaniiana 8 3 11. D. pentzii x D. milaniiana 7 3 12. D. milaniiana x D. milaniiana 0 1 194.2 13. D. milaniiana x D. pentzii 0 0 14. D. milaniiana x D. valida 9 23 — 15. Hybrid 125-1 x D. umfolozi 0 4 16. D. valida x D. milanjiana 9 0 17. Digitaria pentzii A-24 1 16 18. D. pentzii x D. milaniiana 4 7 475.4 19. D. milaniiana x D. milaniiana 10 1 20. Digitaria pentzii FL-720 20 15 292.3 i—< CNj Digitaria umfolozi FL-525 0 22 268.0 22. Digitaria swazilandens is FL-556 16 32 412.7 23. Digitaria decumbens FL-547 14 26 24. D. milaniiana x D. valida 0 34 25. D. milaniiana x D. pentzii 14 11 445.0 26. D. milaniiana x D. milaniiana 0 72 27. Digitaria 1969 Selection 4 15 254.9 28. D. milaniiana x D. milaniiana 0 4 287.2 29. D. milanjiana 0 7 89.2 30. Cynodon dactylon cv . Coastcross-1 32 57 * 3 core samples were taken from selected plots Oct. 28, 1974. Phosphate and molybdate fertilizer added to the cores and sampling for nitrogenase on November 14, 1974. 82 While in Brazil, I also made many root sections of Transvala using a freezing microtome or cryostat. The cortical cells of Transvala roots were often filled with bacteria. The photomicrographs taken were presented in the International Nitrogen Fixation Symposium (_10) . Although positive identifica- tion of Spirillum 1 ipof erum within these cells must still be done using the flourescent antibody technique or by electron microscopy, the evidence contin- ues to accumulate that they are indeed in the root rather than in the rhizo- sphere (15 , 16) . ACKNOWLEDGEMENTS Thanks are due to the staff of both soils and agrostology departments of IPEACS in Brazil for their cooperation in making the experiments possible. In Brazil, special thanks to Dr. Johanna Dobereiner, Dr. John Day, EnesioDelgado de Lucas, Gladstone Abrantes, Rui Melo de Carvalho, Paulo Roberto de Souza Faria, Ricardo Motta Miranda and Jose Bonifacio Meneses who aided in laboratory or field analysis. At Florida, tremendous back-up help was given by Dr. Rex L Smith, Dr. G. 0. Mott, Jan Ferguson, Dave Block, and Charity O'Neil. Dr. John Cornell and staff in the Statistics department of IFAS completed all the sta- tistical analysis. LITERATURE CITED (1) (2) (3) (4) (5) (6) (7) (8) (9) Abrantes, G. T. V., Day, J. M. , and Dobereiner, J. 1975a. Method for the study of nitrogenase activity in field grown grasses. Soil Biol. Intern. New Bui. (Paris) (In Press). , Day, J. M. , and Dobereiner, J. 1975b. Factores limitanes da fixacifo de nitrogenio en campo de Digitar ia decumbens cv. transvala (Presented at the XV Soils Congress, Campinas, Sao Paulo, Brazil, July 1975). Bulow, J. F. W. von and Dobereiner, J. 1975. Potential of nitrogen fixation in maize genotypes in Brazil. Proc. Nat. Acad. Sci. 72: 2389-2393 Day, J. M. and Dobereiner, J. 1975. Physiological aspects of N2_fixation of a Spir ilium from Digitaria roots. Soil Biol. Biochem. (In Press). , Neves, M. C. P., and Dobereiner, J. 1975. Nitrogen fixation on the roots of tropical forage grasses. Soil Biol. Biochem. 7: 107-112. Dobereiner, J. and Campelo, A. B. 1971. Non-symbiotic nitrogen fixing bacteria in tropical soils. Pi. Soil. Special Volume 457-470. , Day, J. M. , and Dart, P. J. 1972a. Nitrogenase activity and oxygen sensitivity of the Paspalum- notatum-Azotobacter paspali association. J. Gen. Microb. 71: 103-116. , Day, J. M. , and Dart, P. J. 1972b. Nitrogenase activity in the rhizosphere of sugar cane and other tropical grasses. Pi. Soil 37: 191-196. , and Day, J. M. 1973. Dinitrogen fixation in the rhizosphere of tropical grasses. IBP-Conference , Nitrogen Fixation and the Biosphere. Edinburgh. (W. D. P. Stewart, Ed.) Vol. 1 Cambridge Univ. Press. 83 (10) , and Day, J. M. 1974. Associative symbiosis in tropical grasses: Characterization of microorganisms and dinitrogen fixing sites. Intern. Symp. N2- fixation-interdisciplinary discussions. Pullman, Washington. (In Press) . (11) Hardy, R. W. F. and Havelka, V. D, 1975. Nitrogen/Fixation/Research: A key to world food? Science 188: 633-643. (12) Hubbell, D. H. and Dazzo, F. B. 1975. Biological Nitrogen Fixation. Soil Crop Sci. Proc. Fla. 35: 71-79. (13) Quispel, A. (Ed.) 1974. The Biology of Nitrogen Fixation. North-Holland , Amsterdam, and Elsevier, New York. Frontiers of Biology, vol. 33, 770 pp. (14) Neves, M. C. P., Nery, M. , and Day, J. M. 1975. Efeito da temperatura na fixacao de nitrogenio de estirpes de Digitaria e milho. (Presented at the XV Soils Congress, Campinas, SSo Paulo, Brazil, July 1975.) (15) Schank, S. C., Day, J. , Abrantes, G. T. V., and Dobereiner, J. 1975. Growth characteristics, nitrogenase activity and yield of two cultivars of Digitaria decumbens ('Transvala' and 'Pangola') digitgrass in Brazil. Abstracts. Southern Branch Amer . Soc. Agron. 2:12. (16) Smith, R. L., Gaskins, M. H. , Schank, S. C., and Hubbell, D. H. 1975. Nitrogen fixation by a tropical grass-bacteria association in Florida. Abstracts Southern Branch Amer. Soc. Agron. 2:12. 84 Figure Legends Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Nitrogenase activity on 'Transvala' digitgrass in Brazil during 1974. Each point on the graph is the mean of dozens of determina- tions summarized to coincide exactly with harvesting dates. Yield data on 'Transvala' digitgrass in Brazil expressed in grams per square meter per day. Harvest dates were every 28 days during 1974. Rainfall data at KM 47 in Brazil during 1974. Data is summarized to show the amount of rainfall in millimeters which fell in each 28 day period preceding the harvest. Comparative seasonal yields of 'Transvala' and 'Pangola' digitgrass during 1974 in Brazil. In Vitro organic matter digestibility (IVOMD) of 'Transvala' and 'Pangola' during 1974 in Brazil. Note the marked decrease in IVOMD during the dry winter period, late July, August, and Sep- tember . 85 21.45 TRANSVALA -- Km 47 I6O-1 150- 140 130 120 no mm 90 80 10 60 50 40 30 20 10 RAIN FA L L AT Km 47 - 1974 Figure 3 86 1 > GRASS -BACTERIA NITROGEN FIXATION IN FLORIDA PRELIMINARY RESULTS By Rex L. Smith, M. H. Gaskins, S. C. Schank, and D. H. Hubbell — ^ The energy crisis and the dramatic increase of nitrogen fertilizer prices has stimulated renewed interest in biological nitrogen fixation. Of special interest to us was the Brazilian work on nitrogen fixation by bacteria in association with grass roots. As grasslands are vast, the potential of these systems is tremendous and could make a very significant contribution toward nitrogen for large acreages. Observations in Brazil on sugarcane and other grasses suggested that nitro- gen was being biologically fixed because yields were higher than expected from unfertilized crops grown consecutively for many years. Nitrogen fixing bacteria (Azotobacter paspal i) were found in large numbers on grass root sur- faces of Paspalum notatum variety 'Batatais' (_1) . Later is was pointed out that most of the nitrogenase activity was associated with washed roots and not the rhizosphere soil. 'Balatais' was found to fix up to 90 lbs. of nitrogen/acre/ year (2^, whereas, other varieties of Paspalum notatum fixed little nitrogen. Conclusions were drawn that the bacter ia-grass associations were genotype specific and that efficient fixation depended upon specific matching of the grass and bacteria (3) . Azotobacter paspal i was found to be widespread and was found in Florida as well as Brazil (j3) . Work on sugarcane showed an association with the bacterium Bei jerinckia indica which was abundent on the sugarcane roots. This bacterium was also active on roots of several other tropical grasses (4). Further work revealed nitrogenase activity with Digitar ia decumbens roots, in this case, the bacterium Spirillum 1 ipof erum was responsible (_5) . Activity varied with genotype; 'Transvala' was lOtimesmore active in fixing nitrogen than 'Pangola'. Preliminary cytological observations of roots by Dr. S. C. Schank (_5) revealed that the organisms were located inside root cells providing a symbiotic system which is considered necessary for efficient nitrogen fixation. Convinced that the great potential warranted intensive research in order to utilize these systems, we initiated research and established a team approach. Our overall, long term objective is to produce efficient commercial systems that will reduce nitrogen fertilizer requirements and increase world food production. Our first work, reported here, was to screen grass genotype for ability to associate with S. 1 ipoferum and fix nitrogen and to establish grass- bacteria associations, by means of inocultion, that would fix nitrogen. In 1974, we screened 40 genotypes of tropical and subtropical grasses for response to inoculation with Spirillum 1 ipoferum obtained from Drs. Johanna 1/ Associate Professor of Agronomy; Plant Physiologist, ARS , USDA; Professor of Agronomy and Associate Professor of Soils, respectively. 87 Dobereiner and J. M. Day in Brazil. The grass genotypes belonged to five species, Digitaria decumbens, Panicum maximum, Paspalum notatum, Cenchrus ciliaris and Cynodon dactylon . Two replications of paired plant plots were used. One plant of each pair was inoculated, the other served as a control. Inoculation was accomplished by applying 100 ml. of diluted (5 to 1) semisolid culture, liquified by a slow speed blender, to each plant crown and watering it in immediately. Control plants received medium without the bacterium in the same manner and amount as the inoculated plants. Inoculation was done two times, the first on July 31st and the second two weeks later. The first inoculum had sparse growth but second was seeded heavily and produced a good culture. The inoculum culture medium was nitrogen free, contained malate (.57>) as the energy source and contained the usual inorganic minerals. The entire nursery received fertilizer at the rate of 0-40-80 with trace minerals added at establishment time. No nitrogen was applied and the soil was well depleted of residual nitrogen. The forage was harvested October 4th and dry matter yields taken. Two varieties gave significantly higher yields when inoculated, 'Transvala' and Pm 285 (Panicum maximum) ; inoculated PM 285 also contained more protein. Dry matter yields and protein content are given in Tables 1 and 2. TABLE 1. --Yield Response to Spirillum Lipoferum Variety Rep I Rep II Mean 7o of inoc. Control G. Dry Wt. Transvala Inoc . 367 223 300 1637, Not. Inoc. 196 173 184 PM 285 Inoc. 1,118 1,339 1,228 1537c Not. Inoc. 850 749 800 TABLE 2. --Crude Protein - percent of dry wt . Rep Rep Mean Variety I II Transvala Inoc . 7A 5.8 6.4 Not. Inoc. 6.6 6.6 PM 285 Inoc . 9.1 10.2 Not. Inoc. 9.2 8.1 8.6 88 Acetylene reduction measurements were inadvertently delayed until after cool nights began. The plants that appeared to respond to the inoculation were moved into the greenhouse to avoid cold damage. Even with light supplementa- tion the plants did poorly so acetylene reduction was delayed further until January. Only two genotypes, both Cenchrus ciliaris , gave favorable results (see Table 3). Here non-inoculated plants appeared to also be infected indi- cating that the organism had moved from inoculated to uninoculated plants, a distance of six feet. Lack of ethylene production in PM 285 and low activity in Transvala was attributed to poor condition and growth of the plants and their inability to supply photosynthate to the roots. TABLE 3 . - -Acetylene Reduction of Grasses in the Greenhouse Variety Spirillum Inoculation + n moles/g/h Transvala 1.2 15.3 Coast Cross .2 3.1 PM 285 1.2 1.4 B 68-12 248.7 45.6 B 1-2 82.9 115.8 This work gave good indications that we established grass-bacteria associations capable of improving yield by inoculation with Spirillum lipoferum and gave responsive varieties for future work. We have been collecting "nitrogen fixing" bacteria from grass roots from Florida and Latin America. We found that enrichment could be facilitated by first surface sterilizing roots for up to 1 minute in 107, chlorox then plating the roots on nitrogen free medium. This process favors bacteria located in- side roots which are of most interest. Recently (Spring 1975) we inoculated field plots several acres in scope. Inoculum was produced in a bacteria fermentor 13 1 per batch (courtesy of Dr. M. E. Tyler and James Milium, Bacteriology Department) . Nitrogen free medium (0.5% malate) was used with 95:5 (^i^^) bubbled through the liquid medium at 35°C. A batch could be produced in 24 hours containing over 200 million organisms per ml. Replicated experiments of those genotypes that appeared to respond in 1974 have been inoculated. Data from these experiments should verify that these bacteria-grass systems can be established artifically by inoculation. This is necessary for us to utilize these systems. We are also screening over 1,000 genotypes of grasses in 12 different species in order to discover more efficient systems and materials for basic studies . 89 LITERATURE CITED (1) Dobereiner, Johanna. 1966. Azotobacter paspal i sp. n. A nitrogen fixing bacteria in the rhizosphere of Paspalum. Pesq. Agropec. Bras. 1: 357-365. (2) Dobereiner, Johanna, Day, J. M. , and Dart, P. J. 1972. Nitrogenase activity and oxygen sensitivity of Paspalum notatum- Azotobacter paspali association. J. Gen. Microbiol. 71: 103-116. (3) Dovereiner, Johanna. 1970. Further research on Azotobacter paspal i and its variety specific occurrence in the rhizosphere of Paspalum notatum Flugge. Zentral- blatt fur Bakteriologie , Parasiteukunde 124: 224-230. (4) Dobereiner, Johanna, Day, J. M, and Dart, P. J. 1972. Nitrogenase activity in the rhizosphere of sugar cane and some other tropical grasses. Plant and soil. 37: 191-196. (5) Dobereiner, Johanna, and Day J. M. 1974. Associative symbiosis in tropical grasses: Characterization of microorganisms and dinitrogen fixing sites. Intern. Symp. on N2 Fixation - Interdisciplinary discussion. (June 3-7, 1974, Washing- ton State University, Pulman, Washington) . 90 GROWING CALVES TO YEARLINGS ON WINTER ANNUAL SMALL GRAINS AND GRASSES PLUS LEGUMES AND SUMMER PERENNIAL GRASSES-7 2 / By Sidney C. Bell — The use of cool season annual small grains, grasses and legumes was eval- uated during 1960 to 1970 at three locations of the Auburn University Agricul- tural Experiment Station (Tennessee Valley Substation, Belle Mina; Lower Coastal Plain Substation, Camden; and Gulf Coast Substation, Fairhope) . Animal gain from grazing yearling beef steers average 416, 390 and 314 pounds per acre for the Tennessee Valley, Lower Coastal Plain and Gulf Substa- tions, respectively. The lower gain per acre at Gulf Coast was attributed to use of this land for double cropping with soybeans. There was a higher stock- ing rate at Tennessee Valley, 1.90 compared to 1.32 at Lower Coastal Plain and 1.19 at Gulf Coast Substation; but the average daily gain was lower at Tennessee Valley, 1.49 pounds compared to 1.58 at Lower Coastal and 1.70 at Gulf Coast Substation. A four-year study, recently completed at the Black-Belt Substation, 1969- 1973, used grazing on wheat and ryegrass grown in rotation with corn silage and soybeans. Pasture was grazed 187.5 days with an average of 1.21 head per acre. Average daily gain was 1.91 pounds per day. Total gain per steer was 358 pounds with a gain per acre of 433 pounds. Steers were purchased at $38.05 per cwt. and sold for $36.23 per cwt . and had a feed and pasture cost of $13.73 per cwt. of gain. This resulted in a return above feed and pasture cost of $61.66 per steer or $74.61 per acre. Budgets were developed from research data using current prices for inputs and $30.00 per cwt. for Stockers (buying and selling price) for three systems, rye, rye-grass and rye-ryegrass-clover. The addition of ryegrass or ryegrass and clover gave about 25-30 more days of grazing and the pasture with clover gave the highest net return to operator's labor and management, $24.48 per acre compared to $14.08 for rye-ryegrass and $3.42 for rye alone. Summer Perennial Grasses Another study at the Black-Belt Substation compared gain and returns on Dallisgrass alone, with Dallisgrass and clover mixture and also half Dallis- grass and half clover. Costs per hundred pounds of gain with today's prices, indicated a big advantage for the treatments with clover. The costs per 1/ Paper presented at 32nd Annual Pasture and Forage -Crop Improvement Conference, Texas A & M Agricultural Research and Extension Center at Overton, Longview, Texas, May 1975. 2/ Professor of Agricultural Economics, Dept, of Agriculture Economics and Rural Sociology, School of Agriculture and Agricultural Experiment Station, Auburn University, Auburn, Alabama. 91 hundredweight of gain were $23.52 for Dallisgrass alone, $16.55 for mixture and $17.62 for half Dallisgrass and half clover. Bahia and Coastal bermuda, at various rates of nitrogen, were compared in a six-year study at the Wiregrass Substation. Coastal had higher stocking rates than bahia and also had higher gain per acre for each level of nitrogen. Gain per acre varied from 259 pounds up to 369 for bahia and from 308 pounds up to 675 for Coastal. At current prices of inputs, including $180 per ton for ammonium nitrate, and $30.00 per cwt. for Stockers, it did not pay to use nitrogen on bahia nor Coastal bermuda. Using $40.00 per cwt. for stockers, the most profitable level of nitrogen was 80 pounds per acre for bahia and 320 pounds for Coastal. Even at $50.00 per cwt. for stockers only 80 pounds of nitrogen was most profitable for bahia. Usfng $120 per ton for ammonium nitrate, the price of stockers had to be $50.00 per cwt. to justify use of 160 pounds of nitrogen on bahia for most profit. At this combination of prices, 320 pounds of nitrogen was most profitable for Coastal. At comparable levels of nitrogen use and prices, Coastal paid from $10.00 to $15.00 per acre higher net returns than bahia. 92 RESEARCH IN TENNESSEE RELATED TO GRASS TETANY By John H. Reynolds — ^ Grass tetany may occur in beef cows grazing tall fescue pastures during the late winter and early spring and is thought to be one of the leading causes of death of adult beef cows in Tennessee. Various investigations have been completed recently or are currently underway to characterize plant and animal responses to forage management that might be related to the incidence of grass tetany. Chemical composition of tall fescue forage has been studied at Knoxville by D. B. Hannaway and J. H. Reynolds. Fescue forage was sampled monthly for two years to determine the seasonal trends of chemical constituents that may be related to grass tetany. Nitrogen and potassium fertilizer rates were varied to find the influence of fertilization on the chemical constituents. Nitrogen fertilization increased the concentrations of potassium, calcium, and magnesium during some of the months when tetany might occur. Malic acid and total organ- ic acid concentrations were increased by nitrogen fertilization while citric acid was decreased. Potassium fertilization increased potassium but decreased magnesium concentrations in the forage. Malic acid and total organic acid concentrations were decreased and citric acid increased by potassium fertiliza- tion. Thus, nitrogen fertilization, at the rates studied--50, 100, and 150 lb. nitrogen per acre--was generally beneficial in changing the chemical com- position when compared with the check. On the other hand, potassium fertiliza- tion at 150 lb. potassium per acre was detrimental because it decreased mag- nesium concentration while increasing potassium and citric acid. These con- ditions have been shown to contribute to grass tetany. Seasonal trends ob- served showed that calcium and magnesium were lower during the cooler months while potassium and organic acids were increased. These seasonal trends in forage composition would tend to favor grass tetany occurrence in the late winter and early spring. Animal science research has focused on seasonal trends of blood serum magnesium in beef cows. Monthly samples of blood were obtained from beef cows at a branch station in each major area: East, Middle, and West Tennessee by Hansard et al . Lowest values of blood serum magnesium were found in February, a month when tetany symptoms might be likely to appear. Average monthly serum magnesium values were below the suggested adequate level of 2 mg magnesium per 100 ml of serum. Another area of attention in animal science research has been the effects of supplemental magnesium on grass tetany incidence in cows grazing stockpiled fescue during the winter. Beef cows fed a MgO-salt mixture or a MgC^-molasses 1/ Associate Professor of Plant and Soil Science, University of Tennessee, Knoxville, Tennessee 37916. 93 mixture were compared with control cows by McLaren et al . at the Highland Rim Experiment Station, Springfield. The number of clinical cases of grass tetany was reduced and the blood magnesium level was increased by magnesium supplemen- tation. The lowest point in magnesium level during the year occurred at the time of calving. After calving, cows consuming supplemental magnesium had a more rapid recovery of serum magnesium to normal levels than cows not consuming supplemental magnesium. It appears that low serum magnesium levels in the beef cow after calving may coincide with high potassium, low magnesium, and low calcium concentrations in fescue forage. These conditions would probably be conducive to grass tetany incidence . Research related to grass tetany currently underway or planned includes the following. F. C. Madsen and S. L. Hansard are monitoring serum magnesium in sheep fed fresh grass supplemented with a readily available caybohydrate source. Persistence of magnesium in fescue forage will be determined byj. H. Reynolds after application of MgO-bentonite slurry to tall fescue leaves. More comprehensive determinations on blood fractions will be made by M. C. Bell and J . B . McLaren. These investigations will also include balance studies in beef cows that are consuming fescue hay and fescue pasture in order to deplete their blood serum magnesium. Seasonal trends of chemical composition of forage samples from tetany- producing pastures will be compared with time of tetany incidence for more complete characterization of causes of grass tetany. REFERENCES (1) Hansard, S. L., Madsen, F. C., Merriman, G. M. , and McLaren, J. B. 1975. Tennessee grass-fed cattle need supplementary magnesium. Tennessee Farm & Home Science Progress Report 93. (2) McLaren, J. B. , Saylor, D. W. , Hansard, S. L., and Safley, L. M. 1975. Effects of supplemental magnesium on the incidence of grass tetany in beef cows. Tennessee Farm & Home Science Progress Report 94. 94 PROGRAMMING MODELS FOR FORAGE-BEEF SYSTEMS By W. A. Halbrook ~ I appreciate the opportunity to appear on your program and visit with you about programming models for forage-beef production systems. This is an area I believe can provide more information for both producers and researchers than the partial analysis of specific production practices. The data requirements, however, are tremendous and require the cooperation of several disciplines. At Arkansas, Dr. Arthur Spooner, Dr. Maurice Ray, and myself have shared the data responsibilities but have been assisted by graduate students and Extension personnel . Least Cost Forage Programs for Beef Cows Our first attempt at forage-beef programming was to apply the linear pro- gramming minimization model to forage production. Logically, the least cost feed mix and the least cost forage mix for beef cows are the same, but opera- tionally, they are two entirely different problems. Input-output budgets were developed for a fall-calving cow herd and for each forage species commonly grown in the area. Budgets were developed for four different fertilizer levels for each species and for deferred grazing and hay in addition to seasonal grazing. This provided 12 different production -- harvesting alternatives for each forage species with the options of hay feeding during any month of the year. Feed requirements were entered in the programming model as minimum amounts of tdn and protein that must be provided each month with monthly limits on the dry matter intake of the animal. Monthly estimates of tdn, protein, and dry matter provided by each production-harvesting alternative were entered as al- ternative ways of meeting the feed requirements of the herd. Appropriate costs were estimated for each production-harvesting-feeding method. The objective was to minimize annua‘1 costs of feeding the cow herd. All forage feeds were required to be produced on the farm but protein supplement could be purchased if needed. Land costs were varied to provide results that ranged from much land and no fertilizer to high levels of fertilizer and less land . Results of the least cost forage programs were then considered at differ- ent stocking rates and evaluated for a fixed farm size to determine the most profitable stocking rate for different cattle prices. 1/ Associate Professor of Agricultural Economics, University of Arkansas, Fayetteville, Arkansas. 95 Results indicated several data problems but one recognized weakness was the difference between feed required and feed actually consumed under pasture conditions. If only enough feed were provided during the dry period, and if no pasture rationing were practiced, it is possible that the herd might over- graze and damage the stand. The least cost forage program for beef cows is not a complete systems model but can answer some questions that are not adequately answered with cost- returns budgets. Forage-Beef Systems Model About six years ago, a southern regional research project (S-67) was initiated. One objective of this study was to develop a programming model that could be used to evaluate forage-beef production systems in the south. Each state took a slightly different approach to the work, but some general guidelines were established to provide for a certain degree of uniformity. Some of the general procedures for the study were that (1) each state would develop a set of forage production-utilization budgets that would re- flect the costs of producing and utilizing forage feeds, (2) each state would develop a set of beef cattle budgets that would reflect cow-calf, Stockers, and feeding activities appropriate to state, (3) minimum amounts of tdn, protein, and maximum amounts of dry matter would be determined for each beef cattle activity from the 1970 edition of "Nutrient Requirements of Beef Cattle," (4) the beef cattle and forage budgets from each state would be reviewed by a committee composed of agronomists, animal scientists, and agricultural econo- mists to provide for as much uniformity as possible, and (5) the forage and beef cattle data would be incorporated into a linear programming model to program the most profitable forage-beef cattle systems for a given set of conditions . Practically all the basic parts of this objective have been met by the par- ticipating states. Forage and beef cattle budgets have been published by most states. Programming work is still in prograss with revisions of price and basic production data. It will probably be another year before programmed results are such that the researchers feel comfortable with the findings. I would like to share with you some of the problems we encountered at Arkansas with this study. These problems will not be new to many of you since you have been involved with the study in your state. 1. Adequately depicting the Production-Utilization Surface: Production- utilization budgets can be prepared with the best available data and still have programmed results that indicate data weakness. At Arkansas, the early pro- gramming results pointed to weaknesses in forage production data at low levels of fertilizer. 2. Data Mass: To adequately depict all the forage-beef alternatives in a linear framework may require up to 500 different forage and beef cattle activities with 20 to 60 bits of information for each. The time and human errors involved in developing this amount of data and converting the data to a programming framework creates several problems. 3. Feed restrictions: Some early programming results indicated that either (1) tdn, protein, and dry matter do not adequately describe feed quality under pasture conditions or (2) our estimates of tdn, protein, and dry matter are not adequate during certain parts of the growing season. 96 4. Algebra: Maximum dry matter restrictions as used in the model required that any excess capacity be with the animal. This means all dry matter pro- duced must be consumed. On an annual basis, this would be desirable since it would demand complete utilization of the forages. On a monthly basis it may not be economical to stock enough animals to consume all the production during peak production. 5. Proportionality: The proportion of tdn, protein, and dry matter pro- duced are not the same proportions as required by the animals. Since tdn, protein, and dry matter were stockpiled as produced and withdrawn according to animal requirements, this created some programming problems. 6. Economic Obsolescence: The time required to develop programming data can render the prices obsolete by the time results are available. This has been especially true during the last five years. The above mentioned problems represented challenges to the researchers involved and all have been, or are in the process of being, solved. Rather than dwell on the different methods that have been used to eliminate the pro- gramming problems of the S-67 project, I would like to spend the remaining time reviewing some developments that will make forage-beef systems programming more realistic for future research. Budget generators that have been developed in recent years will make it possible to assign many of the calculations to the computer and thereby reduce human errors, reduce the time involved, and provide for uniformity of calcula- tions. Once a basic set of budgets has been developed it can be updated for changes in prices very quickly and eliminate some of the conomic obsolenscence . It also represents a necessary line in making the programming results appli- cable to individual farm situations. Matrix generators are not to the stage of development as the budget generators but, when operational, they will reduce the time required and the errors inherent in transferring budget data to a programming matrix. They represent another tool of making forage-beef systems programming a workable reality. Computer subroutines have been developed that can quickly calculate the feed reuirements for different beef cattle at different levels of production. Linear programming will likely be the princiapl model used for general forage-beef systems analysis. However, we are likely to see certain aspects of the "Simulation" model used to supplement the linear model. For certain types of beef cattle analyses, such as cow-calf systems, we may see the linear model supplemented by some of the investment models since certain aspects of beef cow herds fit well into the investment framework; 97 *-1976-R.P.0.-1750-$/671-5R3/70 Library onjVonetyp^00 0ffice •S- Dept. Of Agr/cu Itur jre U. S. DEPARTMENT OF AGRICULTURE AGRICULTURAL RESEARCH SERVICE SOUTHERN REGION P. O. BOX 53326 NEW OR LEANS, LOU 1SI AN A 70153 OFFICIAL BUSINESS PENALTY FOR PRIVATE USE, S300 POSTAGE AND FEES PAID U. S. DEPARTMENT OF AGRICULTURE AGR 101