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New York State Colleges 


Agriculture and Home Economics 

Cornell University 



" DEC! 

3 1973 






S 679.B3 

Cornell University Library 

Vertical farming 

3 1924 000 349 328 

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Cornell University 

The original of this book is in 
the Cornell University Library. 

There are no known copyright restrictions in 
the United States on the use of the text. 






56 T 9 


:.'.-.■.. ,i ", .'". ;;SiObPYniGHT, 1915 


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The Origin and Character of Soils 

Soils Are Rock Waste. — Soils were not originally a part of 
the earth's surface, but have been formed slowly by the crum- 
bling and breaking up of the surface rocks into fine particles, 
such as clay and sand. Sometimes this breaking up occurred 
where the soils are now found, and the character of the soil is 
governed by the kind of rock that was left on the surface, 
while in other cases the rocks and the soil that came from them 
have been carried thousands of miles and mixed with other 
material, forming a conglomerate mixture from many sources. 
The highland and mountain soils in this country have, as a rule, 
been formed very near the places where they are now found, 
while the soils in the larger valleys, and along most of the 
coast line, have resulted from material washed down from the 
hills and deposited along the level stretches near the sea. 
Much of the soil of the more northern states has been brought 
down from Canada by the movement of ice along the surface. 

This breaking down of the rocks and formation and moving 
of the soil has taken a long time; but this work is yet going 
on, and the exposed rocks, boulders and ledges in our fields and 
mountains are yearly being attacked by the different forces, 
and are slowly yielding up material to help replenish the older 
soil. Different natural and artificial processes are also going 
on in the soils that may either improve or injure them. Most 
of these processes can be controlled by man and made to be his 
servant, so that he can become a great factor in the formation 
of profitable soil. 


The breaking down of the original rocks has been accom- 
plished by very simple means, the action of which has been very 

Work of the Atmosphere. — Everyone knows how a piece of 
iron is attacked and falls into a powdery iron dust, which is 
nothing but iron combined with oxygen taken from the air to 
form a different substance called iron oxide. The oxygen, 
carbon dioxide and other gases of the air attack the iron, lime 
and other elements in the rocks, forming new substances and 
causing the particles to fall apart, as is the case of the iron 

U. S. G.S. 


rusting. Rocks are also carved, eroded and worn away by the 
cutting and sawing action of the wind, especially when it carries 
with it any considerable amount of dust or sharp sand particles. 
In this way large rocks are sometimes entirely worn away. In 
some localities in this country the sand is swept across the level 


stretches so severely as to smooth off the rough places on brick 
walls, and to scar the glass in windows. 

U. S. G. S. 


The Part Played by Water. — Much rock material is slowly 
dissolved out and carried away by rain water. This is usually 
carried long distances before being thrown back into a solid 
• state by the evaporation of the water, or by coming into con- 
tact with some other substance that causes it to be precipitated. 
Often this reforms into another rock that may be harder than 
the original one. 

A much greater effect of water, however, is in the formation 
of ice, which expands and acts as a powerful wedge in splitting 
off small fragments. You will often notice along the foot of a 
cliff, or at the base of a large rock, a mass of small splinters of 
stone that have been pried off the parent rock in this way. 
Running water also slowly wears away even the hardest rocks, 
reducing their close material into finer particles. 




Glaciation. — During the glacial age vast sheets of ice, carry- 
ing with them boulders and everything else that was movable, 
passed over much of the United States and Canada, and ground 


up the rocks into soil. Large areas of the richest soils were 
formed in this way. Smaller movements of ice occurred in 
the valleys of the Northwest and resulted in the formation of 
some wonderful soil areas there. These movements of ice 
leveled down the rough surfaces of mountain ranges and 
scoured out wide valleys. 

Variations of Heat and Cold. — The variations of tem- 
perature from day to night and from summer to winter have 
also been busy in grinding out soil meal. When it is warm 
the rocks expand slowly, and contract under lower temper- 
atures. The different minerals in the rocks expand and con- 
tract unequally, causing cracking which flakes off the outside 
of the rock and permits of its being attacked much more easily 
by other agents of destruction, or perhaps, better said, of 
creation. The effect of these changes of temperature are more 
noticed in some of the higher and drier regions where the hot 
evening gives way quickly to cold night. It has been reported 
that this action is at times so violent as to split large pebbles in 
half so quickly that a noticeable report, like the bursting of a 
percussion cap, is made. 





Plants Render Assistance. — Just as soon as a little powder 
is formed from the rocks by the action of these agencies, minute 
plants, some of which can be seen only by means of a micro- 
scope, fasten on the rock meal and begin to grow. As they 
mature and die, their tiny bodies add the first organic matter 
to the newly formed soil and help prepare it for larger and 
more vigorous plants. The study of this action is very inter- 
esting, and a short search into any stony place will reveal many 
examples. Mats of short moss will be found growing on what 
seem absolutely dead and impervious stone. Trees can be 
found sending their roots into the smallest fissures in the rocks 
and bursting them wider. It is a hard life for these plants, 
and their growth is slow and stunted, but it is one of their 
missions in nature and they go on with the heavy work, giving 
to man at the same time a wonderful revelation of what he can 



accomplish in the way of improvement by giving cultivated 
trees and smaller plants a suitable place to grow, rather than 
force them to combat all the adversities of a resistant soil. 

Animals Help. — Tiny worms and bugs soon begin to burrow 
into the weaker points of the rocks, and as the work goes on 
much larger cousins follow them. Their action is to open 
channels through which water can reach more effectively the 
harder rock within. They also do large amounts of grinding 
and mixing on their own part. Their excretions and their dead 
bodies add more organic matter to the soil and help pave the 
way for a good garden or a fruitful field. 

*«•**■-■« -:. - Jl *■ 

U. S. G. S. 


Each Force Helps the Others. — These forces in their slow 
work of grinding up the rocks into earth meal do not work 
separately, but each helps the other. When one worker has 
opened a way into the rock, his success is immediately fol- 
lowed by activities on the part of the others. The roots and 
worms open channels to permit the entrance of more water, 
which may mean more freezing and more cracking, and there is 
more room for roots. An expansion crack works the same 
way. The pits made in the face of the rock by the action of 
the air make suitable homes for the mosses and other plants. 
It is a big job, and the work is accomplished only by all hands 
keeping busy. 



The Formation of Humus.— The rock powder or meal does 
not of itself make a desirable soil, and other matter must be 
added. Microscopic plants must nourish to help in the work of 
crop production ; water must be present, and as a rule, the more 
humus the better the crops. This humus is not a strange sort 
of stuff at all, as it is only rotten trash from dead plants or 
animals. Mention has already been made of how its first start 
is made. This is later augmented by the growth of larger 
plants which have more leaves, twigs and roots to rot. In 
increasing the amount of humus in a soil the work of man, 
when intelligently applied, can be made to do wonders. 


How Soils are Moved. — After the agencies just described 
have ground out the rock powder, nature keeps right on at 
work in moving and sorting out the soil particles. This work 
is done by the action of : 

Gravity. — The soils formed on the mountains and cliffs fall 
to the base forming a heap of debris which is called " tallus." 
Where the slope is steep, this falling is immediate ; but where 
the land is more level, the movement is slower and is more of a 
slide than a fall. Gravity is ever at work moving soils from 
high to low levels. 




Water. — Every drop of water that falls on the earth can 
move a particle of soil at least a little distance. These drops 
of rain run together to form rivulets, each with its little load 
of soil. Rivulets meet to form streams, and these join to form 
creeks, and the creeks unite to form rivers. A creek or river 
in flood-time is a stream of soil moving down from the factory 
to be spread out over distant valleys and plains, or to fill up the 
bottom of the sea so that it can finally be used by man to grow 
food and raiment. 

Glaciers. — The great sheets of ice that have already been 
described moved great distances, and carried with them large 
amounts of soil and soil material. Some of them moved from 
Canada into what is now the United States, and brought fertile 
material far within our borders to make some of the richest 
land in the world. 

Winds. — The housekeeper knows how fast dust accumu- 
lates over everything, and how it thickens on furniture and 
carpets if left undisturbed for even a short time. The winds 


have been busy, not for days but for centuries untold, picking 
up soils in one place and dropping them in another — sorting 
and arranging them until it is probable that any given section 
of land anywhere contains particles contributed by every other 
section in that district. 

Residual Soils. — Not all soils are moved in these ways. In 
places, sometimes large, sometimes small, the original rocks of 
the locality have weathered down into soils that remain just 
where they were formed. These are known as " residual soils," 
and embrace a great variety, some of which are fertile, while 
others are not so well favored. The proportion of residual soils 
to transported soils varies greatly in the different parts of the 

Some of the Physical Characteristics of Soils. — Soils have 
a number of marked physical characteristics, some of which are 
of interest only to the exact scientist, but many of these char- 
acteristics are of the greatest interest to the poorest farmer. 
The greatest advances made in the Science of the New Agri- 
culture have been due to the study of these physical character- 
istics of soils, and the application of the discoveries along this 
line have tended toward a better and more profitable agriculture. 

Soil Texture. — One of the most noticeable differences in 
soils is the variations in the size of the grains of rock powder of 
which they are made. The fineness of a soil is spoken of as its 
" texture." The sizes of grains most discussed and best under- 
stood both by the student and farmer are : clay, silt, sand, 
and gravel. It is well known that sand, loam, and clay soils 
will not raise the same crops equally well. There are good 
reasons for this. In a sandy soil the particles are relatively 
large and do not pack so closely together. No matter how 
tightly packed a soil may be, there are always small openings 
and cavities between the particles. These are called " pores." 
The sandy soils do not pack so closely together as do the clays, 
and the pores are therefore larger and permit a much easier 
movement of water and air in the soil. The clay soils pack 
more closely together and reduce the size of the pores so that 


both the water and air move more slowly. The silts and loams 
are intermediate between the sands and the clays. Loam soils 
are made up of mixtures of fine and coarse soil particles. If 
the loam carries a large percentage of sand it is known as a 
sandy loam; if the clay particles predominate in amount, it is 
known as a clay loam. The presence of gravel among the other 
particles materially affects the texture of a soil and often the 
fertility as well. When a considerable amount of these particles 
are present in a loam soil it is usually called a gravelly loam, the 
difference in clay and sand being maintained as before. The 
intermediate textures, such as fine sandy loam, silt loam, and 
the lighter clay loams are usually considered the best, as they 
tend to be light, well drained and easily cultivated. 


When the percentage of fine gravel and coarse sand is high, 
the soil is likely to be too loose, too easily drained, and not 
likely to withstand drought well. Such a soil, especially in the 
rainy regions, is likely to be deficient in one or more of the 
chemical elements needed for the production of plants. Where 
the percentage of fine silt and clay is high, the soil is likely to 
be cold, heavy, and sour. Such a soil, unless well tilled to con- 
siderable depths, resists the ready movement of air and moist- 

Soil Structure. — Another important physical characteristic 
of soils is the way the particles arrange themselves as they lie 
in the field. A coarse sand is found to have every particle 
lying separate, and alone with no attachment to the particles 
which it touches, unless they are cemented together by excesses 
of lime or similar substances. The clay in a path will be found 


to have its particles arranged in much the same way as the sand, 
with the important exception that each is pressed close to its 
neighbor and bound there by cohesion, by adhesion, by some 
other substance present, by interlocking corners of the parti- 
cles, or by other means. When such a soil is disturbed it does 
not fall apart like sand, but remains in close, hard lumps or 
clods. In these soils we have the extremes of structure — the 
open structure, or the individual grain and the dense structure 
or arrangement of the pubbled soil. A well- 
tilled plat of clay or loam will be found to 
have an entirely different structure. Here 
the fine particles of clay, silt and sand are 
bound together in little groups or crumbs. 
These crumbs or granules can be easily de- 
tected by picking up a handful of the soil and 
gently breaking it apart. These crumbs DIAGRAM f soil 
lie close against other crumbs, but unless granules 
poorly handled in cultivating they do not be- 
come sealed together. This is the ideal structure of a soil, and it 
is toward the formation of such granules that we should direct 
our attention, especially in the heavier soils. When such a soil 
is cultivated wet, the pressing action of the plow or harrow 
tends to force the particles closer together and to form the 
undesired puddled structure; but if the moisture content is just 
right, the same plowing will tend to. make the granulation still 
better. Additions of humus material, and, on some soils, of 
lime, help also. 

Such a crumb structure in a soil brings about most of the 
benefits and advantages of both a sand and a clay. It drains 
well, and because of its open structure warms up well in the 
spring. The openness permits easy and good plowing. The 
fine particles absorb and hold the large amount of water needed 
for the crop, and if properly cultivated to preserve this moist- 
ure, will tide heavy crops over longer periods of rainless times. 
Another great advantage of the crumb or open structure of 
clay and loam soils is that they allow the roots to grow quickly 
to great depths. This affords the plant a much larger amount 



of soil from which to draw moisture and food, and consequently 
yields heavier crops. In another paper the good effects of this 
open structure on beneficial bacteria will be pointed out. 

Hardpan and Plow Soil. — Another soil structure that needs 
attention is hardpan. Sometimes this is simply the tight pud- 
dled clay that has already been described ; and sometimes it is 
clay, silt or sand that has been cemented together by some 
chemical or mineral substance in the soil, or by the soil particles 
themselves being so tightly pressed together that they prevent 
the movement of water and air, and retard the growth of roots. 
One kind of hardpan is called plow sole, and is found just at 
the bottom of the plowed furrow where the slide of the plow 
has been for years packing down the soil just where it needs to 

•fi^PLOWio' si/ii'a, ■ * ■ ■i.'jived 'si/REACE*::y.;: 

\'-;PLOWCO lurr/r- 

v open soil to '■: 
: medium depth::- 


be opened. The relief from such conditions is found in deep 
cultivation that will crack the material to pieces and permit 
good drainage where it is bad. This breaking must, of course, 
be deep enough to reach the seat of the trouble. Any adverse 
conditions, such as an excess of alkali or a lack of lime, should 
be immediately corrected. 

Soils and Subsoils. — By soil we mean the surface as con- 
trasted with the lower stratum of subsoil. Ordinarily they have 
come from the same source, and at times are so much alike that 
it is hard to distinguish between them. This is particularly 
true in the semi-arid regions, and in the deep aluvial belts. 
Usually there is a difference in texture, structure, and color. 
The soil has been well weathered and has undergone changes 


that will permit the giving up of its mineral plant foods to the 
roots of plants. These changes have gone on more slowly in 
the stiffer subsoils, and much of the mineral substances have 
not been acted upon sufficiently by the air and by bacteria to 
give up the needed foods. Deep cultivation and the use of 
explosives open up these soils to the action of the air and other 
agencies so that these foods may be prepared for the roots, and 
increased fertility and greater returns in crops are the result. 

Soil Areas, Series, and Names. — The soils of the United 
States are classified into thirteen subdivisions called " Soil 
Provinces," or regions, according to the essential geographic 
features, such as the Atlantic and Gulf Coastal Plains Province, 
the Appalachian Mountain and Plateau Province, the Great 
Plains Region, the Arid Southwest Region, and the Pacific 
Coast Region. The soils of a province are classified in soil 
series. The soils in a series have the same range of color, same 
general character of subsoil, a common or similar origin, about 
the same structure, and broadly, the same type of relief and 
drainage. The soil series are divided into individual soils, which 
generally receive local names, as : Portsmouth Sandy Loam, 
which is found in several states from Delaware to Mississippi ; 
Vermont Silt Loam, of Kansas and Texas ; and the San Joaquin 
Fine Sandy Loam, of the Pacific Region. A soil class includes 
all the soils having the same texture, and are called : sands, 
loams, clays, fine sandy loams, clay loams, clay loam adobe, or 
such other combination of descriptive words as best fits the 
peculiarity of the soil. 

Maps of the soil surveys of the various provinces, and 
descriptions of the series and individual soils of the surveyed 
areas will be found in the annual reports of the U. S. Bureau 
of Soils, and may be consulted at the larger public libraries; or 
if a particular county has been mapped, the report on it can be 
gotten from the U. S. Department of Agriculture. 

Chemistry of the Soil. — While it is true that the productive- 
ness of a soil depends more on its physical character and con- 
dition than upon its chemical composition, yet the chemical ele- 


ments are of great importance and must be taken into consider- 
ation. Many chemical elements are needed for the production 
of a plant, but it is seldom, with the exception of potash, lime, 
phosphorus, or nitrogen, that any of these is not present in 
sufficient amounts. All of these except the last named occur in 
many rocks, and are therefore found in the soils in varying 
amounts. When, on a particular soil, one or more of these is 
absent or deficient, it is necessary to add it in some form of 
fertilizer or manure. 

The soil particles may not be weathered enough to make these 
minerals available, or there may be little in the surface soil and 
more in the subsoil. In either case the soil is improved and 
the plant food brought within the reach of the crop by breaking 
and stirring up the land with explosives. 

Fertilization and Chemical Correction. — In addition to the 
proper physical condition, it is necessary to have the chemical 
condition of a soil well regulated in order that we may get the 
proper returns from our labor. Some foods may need to be 
added to the soil, or it may be essential that a harmful sub- 
stance be removed or neutralized. This work will be considered 
in a following chapter. 



i. Describe the formation of one type of soil not made from 
rock particles. 

2. Does the action of the air always soften freshly exposed 

rocks ? 

3. Name the forces that have been most effective in forming 

the soils in your vicinity. 

4. By what agencies have your soils been moved? 

5. Is the typical soil of your farm finer or coarser than the 

underlying subsoil ? 

6. Can a mixture of coarse sand and clay become as tightly 

compacted as a dense clay? 

7. What, in detail, are the processes in the formation of plow 

sole on your typical soils ? 

8. Why are arid soils less troubled with shortages of plant food 

than humid soils ? 

9. What physical characteristic of your soils lends itself most 

readily to improvement? 




Fertilizers and the Chemical Properties 
of the Soil 


The fertility of a soil is its ability to produce crops. It is 
not one condition, or two or three conditions, but the sum of all 
conditions. It does not consist simply in hauling manures or 
buying chemicals. It means that the water, air, temperature, 
soil bacteria, tilth, and plant food or soil solution exist in the 
right conditions and proper balance as well as in proper amount. 
It is possible for seed to sprout, the crop to grow and ripen, and 
the yield to be the best only when all these conditions are ful- 
filled. Mere richness in mineral foods avails nothing if water 
is lacking to maintain a large amount of soil solution for the 
roots to absorb. The plant food may be there but may not be 
soluble and cannot be absorbed. It may be soluble, but in a 
form distasteful to and therefore rejected by the roots. 

All soils, even those considered poor, contain vast amounts 
of plant food that is not naturally available, but which can be 
converted into an available form. In such a case the problem 
is one of condition and not one of total 'Content. A worn out 
soil is often only an unsanitary one and can be rebuilt to a high 
state of productivity by proper cultural methods. 

Chemical Properties of the Soil. — While hundreds of min- 
erals are known to science, only a few are used in nature in 
forming the common rock from which most soils are derived. 
The more important of these to the farmer are potash, phos- 



phorus, and lime, as these are at times deficient or else appear 
to be deficient. Such elements as iron, aluminum, and silica 
may be ignored, as they are nearly always present in sufficient 
quantity to more than supply any demand made on them. 

For most agricultural conditions it is almost imperative that 
the soil be not acid. The chief corrective for a sour condition 
is lime, which is usually present in sufficient amounts for a 
food, but in many soils is needed to overcome the sour condi- 
tions produced by vegetable decay or bad drainage. It may be 
added in several different forms. At present, carbonate of 
lime or finely ground limestone or marble dust is largely used 
for this purpose. This form is preferred by many on account 
of there being no danger of trouble from an over-application. 
Hydrated lime is also largely used, as is rock or quick lime. In 

Courtesy CJioih's Warner Co. 




using the last named form, care must be exercised to prevent a 
heavy application from burning the organic matter or humus 
out of the soil. Ground or burned sea shells are also extensively 
used and make an excellent form of agricultural lime. Gypsum 
is used under certain conditions. Lime also has a material 
effect on the structure of the soil, especially when it has a 
tendency to be sour, by- causing it to granulate better, thereby 
increasing its power to absorb and hold water. Especially in 
the east and southeast the use of lime is imperative for the best 
success in growing alfalfa and certain other legumes. The 
cow pea seems to resist a sour condition in the soil remarkably 
well. Lime also helps somewhat to liberate potash from resist- 
ant minerals. Salt is sometimes used for the same purpose. 
The growth of nitrogen fixing bacteria is greatly stimulated 
when lime is added to make up any deficiency that may exist in 
the natural soil. 

Potash is a highly essential plant food. It exists naturally in 
most soils and in some of them is found in large amounts. In 
some soils, notably coastal plains sands, it is present in but 



small amounts and must be added artificially. Considerable 
amounts are found in natural manures, but the great supply is 
imported into this country from Germany. 

Phosphorus is also present in most normal soils, but the per- 
centage is small in some of the most valuable soil provinces of 
the country so that it must be added artificially. Large amounts 
of phosphate rock are mined in this country. The rock may be 
ground and added to the soil in the form of a fine powder, pro- 
vided the soil has a good supply of organic matter. If this 
organic matter is deficient and the soils are thin, the best results 
are reported ,f rom the use of acid phosphate which is the phos- 
phate rock after it has been treated with sulphuric acid. Large 
amounts of phosphorus are used in the form of slag and bone 
products. The United States is more than self-sustaining in 
the supply of phosphates and export large amounts annually. 

Another of the important elements is nitrogen, which is found 
in the form of nitrates in some of the desert regions. In this 
form it is very soluble and is washed out of the soil by rains. It 
is found in normal agricultural soils in varying amounts, but is 
often in too small quantities. Commercially it is obtained from 
fish and packing house scrap, from cotton seed, from nitrate of 
soda imported from Chili, and from the air. Nitrogen is a gas 
and makes up the larger part of the air, from which it may be 
taken in large amounts by certain bacteria growing on the roots 
of legumes and by other microscopic plants working alone. 
Further mention will be made of this later. 

How Plants Feed. — Plants feed by absorption through the 
roots and by inhaling the air. When' a plant is burned, most 
of its weight is lost in the form of gases and but a small part 
is left as ash. The ash contains the mineral matter which came 
originally from the breaking up of the soil minerals, or was 
added as a fertilizer. The rest, or the part that was lost in the 
gas is .made up of carbon, hydrogen, oxygen, and nitrogen. The 
carbon is taken in through the leaves from the carbonic acid gas 
of the air. The hydrogen and the rest of the oxygen are taken 
in through the roots in the form of water, and the nitrogen is 



derived from the soil where it may have accumulated from arti- 
ficial supplies, from the action of bacteria, or from the decay 
of organic matter. The relative amounts of these elements 
demanded by different plants varies considerably, as some re- 
quire a large supply of one food element while others can grow 
well with much less of it. 

Only the root hairs, the most delicate 
part of the root system, can absorb foods. 
These are tiny threads growing out from 
the roots just back of the tiny feelers or 
root tips that thrust themselves through the 
soil. The walls of these root hairs are 
very thin and absorb the soil solution direct 
as they lie in close touch with the soil par- 
ticles covered with their thin coat of " Min- 
eral Soup." These dissolved mineral foods 
then pass on into the circulating system of 
the plants as sap, and are carried up to the 
leaves. The sap in conjunction with the 
carbonic acid taken in by the leaves then 
forms the starch, sugar and similar com- 
pounds of the plant and the excess of water 
is lost through the leaves. The amount of 
water evaporated in this way is enormous. 
It has been found on experimentation that 
it requires from 200 to more than 600 pounds 
of water, passing through a plant in this 
way, to make one pound of dry crop. 
These large amounts of evaporated water 
show how necessary it is to keep the soil in 
such a condition that it will absorb the maximum amount of 
rainfall and hold it to supply the growing crop. It is also 
necessary that these tiny root hairs, that are so small that it 
would take 300 or more laid side by side to cover an inch in 
width, be able to creep and grow always deeper and further 
into the soil, unhindered by impacted soil, hardpan, or other 



The roots do not reach down to all of the water they use. 
Some of it is pumped up to them as oil rises in a lamp wick, by 
capillary action. This rise is much faster in well granulated 
soils than in hardpan or tight clay. It is evident, therefore, 
that no method of cultivation can reach down deep enough to 
overcome the difficulties of feeding roots except blasting the 
subsoil with explosives. 

Unavailable Plant Foods. — Attention has already been 
called to the large amounts of mineral plant food bound up in 
insoluble minerals, and to the enormous amount of the highest 
priced plant food (nitrogen) that is present in the air but not 
directly available to the field crops as food. The changes that 
some of these must undergo in order that they can nourish the 
roots are chemically very complex, but, in the practice of the 
art of fanning, can be well controlled. The nitrogen must be 
combined with oxygen. This change is most effectively brought 
about by a certain group of bacteria which grows in knots on 
the roots of peas, beans, clovers, alfalfa, and kindred plants. 
They breathe in the free nitrogen gas and combine it with other 
elements in such a way that large amounts are fixed and held 
in the soil in a combined form that is very nourishing to suc- 
ceeding crops and also to the crop with which they grow. Other 
forms of organisms accomplish the same purpose, working 
without the assistance of the leguminous associates. Both forms 
require certain well defined conditions in which to work. Each 
of these is so essential that it would be hard to name the more 
important one. The soil must be well drained so that there is 
no clogging up of the soil pores with water, but at the same time 
the soil must be moist. The soils must also be warm, for the 
activities of these wonderful little farmers' aids are retarded if 
stopped by frost. Large supplies of air are equally essential. 
As most of these conditions attend a deep tilled soil, it might be 
said that the beneficial bacteria of the soil are all deep tillage 
enthusiasts. They are found at considerable depths in the 
porous types of soil, but cannot live much below the surface in 
tight clays and hardpan. They also keep busy on insoluble 






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forms of combined nitrogen that may be added to the soil, and 
convert it into usable forms. 

Soil changes also materially affect the availability of phos- 
phate material. In nature it is always combined in slowly 
soluble compounds. In commercial fertilizers it is usually com- 
bined with lime. Different relations in the amount of lime to 
the phosphorus effect the solubility of the phosphorus. In 
badly drained land the phosphorus is often found combined 
with iron in little balls of " bog ore " that are very insoluble. 
Many other examples of combinations of plant foods could be 
brought out going further to show how the air, water and 
bacteria assist the changes. In every case the benefits brought 
about demand deep stirring of the soil, such as is produced by 
exploding small charges of slow powders in the subsoil and 
opening a way for the liberators of plant food. No other 
practical method can bring about the desired results. 

Deficient Plant Food. — If the rocks from which a soil is 
derived are deficient in any needed food, it becomes imperative 
sooner or later to add some material that will make up the 
deficiency. The original and best general fertilizing material 
is manure, as it adds not only certain amounts of plant food, 
but also large amounts of humus. Forest mould, litter, straw, 
and other materials of like nature add some of the fertilizing 
elements and also humus. The number of materials that may 
be used to add plant food is great. Some materials carry but 
one needed element, while .others carry two or three. There can 
be no general rule promulgated to guide in choosing fertilizers, 
as different soils and different crops demand certain chemicals 
in different forms. 

Soil Amendment or Correction. — Some soils well supplied 
with mineral and organic plant foods have some trouble, such 
as sourness or an excess of alkali. Materials not classed as 
foods are used in the correction of such conditions. These 
materials are generally known as " Soil Amendments." In the 
correction of black alkali, gypsum is added to change the sodium 
carbonate to a less harmful compound which can more readily 
be leached out. 



The other great amendment is lime, the chief use of which 
has been described in the correction of sour or acid soils. 

Use What You Already Have. — From the foregoing we see 
that there are supplies of practically all the plant foods in 
normal soils, and that additions of fertilizing materials, while 
absolutely essential in some cases, are expensive. Some of the 
foods already in the soil are not in the form needed by the plant, 
but can be changed into usable forms by properly controlled 
natural agencies. The agencies needed for these changes are 
always at their best under certain soil conditions. For the 
different changes the conditions are identical — a moist but 
well drained soil, an abundant supply of air in the soil, the pres- 
ence of more or less humus, and a suitable temperature. To 
obtain most of these is easy, when we consider pnly the soil, as 
it can be done with a plow, but the surface is not half of the 
farm — we want to use several feet of depth 
for a good reservoir for moisture, a factory 
to rework and prepare the foods, and a good 
home for the roots. This naturally de- 
mands that the clay or hardpan be broken 
up. The plow cannot get down to the 
trouble and there is but one other agent that 
can do the work — a reliable low-freezing 

Making Fertilizers More Effective. — 

Heavy applications of fertilizers to force 
bumper crops are attended with certain 
dangers. If everything goes along all right, 
and there is always plenty of moisture to 
dissolve the fertilizers and prevent the 

(greatly enlarged) 


soil solution from becoming too rich, the desired results will in 
all probability follow. In most regions where such fertilization 
is practised, such constant supplies of soil moisture are not 
always to be relied upon. The result is that when the young 
plants get vigorously started on their nourishing ration and 
then meet a season of drouth they are " scorched " or " burned " 


by the too concentrated food, and are left in worse shape than if 
there had been no fertilization and they had been forced to draw 
all their food from the soil minerals. 

Even where the conditions are normal rather than extreme, 
the increased growth caused by the fertilizer calls for a greater 
supply of moisture to support the enormous loss through evapo- 
ration from the leaves, and the fertilizer has in no way met 
the increased demand for the water. The correction for either 
condition is simply the prevention of excessive amounts of the 
water being lost by drainage and holding it stored in a deep 
tilled, open subsoil. A tight subsoil will not absorb and hold 
the moisture in this way and needs the welcome relief of a 
small amount of well placed explosive to shatter and open the 
soil, so that it can meet the demands for more water. 


i. Name in full the conditions necessary for heavy yields of 
your money crop. 

2. What fertilizing material is lacking in your soil, and in what 

form would you supply the deficiency ? 

3. Do the large brace and tap roots of plants absorb plant food 

from the soil ? What is their duty ? 

4. Will a large tree draw most of its food from the ground 

immediately around the stump or from the soil further 

5. What is the source of the most used chemical fertilizer in 

your community, and how is it prepared before being 
offered for sale? 

6. What effect has lime on clover on your farm? On wheat? 

How can you prove your statement ? 

7. Which shows wilt first during a season of slight rainfall, a 

heavy or light crop? Why? 



Soil Moisture 

Crops must have sufficient amounts of water at the right 
time. The greatest demand for water is often during the 
season of least supply. The water must come from the feeding 
zone of the roots within the soil. No phase of agriculture is of 
more importance or worthy of more study than how to main- 
tain an adequate supply of soil moisture. A soil may be rich 
in plant food and not have water enough to dissolve it and carry 
it to the plant roots. Nothing reduces the fertility of the soil 
and the yields of farm crops in the United States annually more 
than the lack of a proper supply of water at the season when 
the crops demand it. The rainfall may be deficient or too 
unevenly distributed so that the farmer is forced to store water 
somewhere and in some way. There are few sections of the 
country where this is not necessary ; where there is rain enough 
during the growing season to water the crops. They must draw 
their supplies from reservoirs that are above or below ground, 
and the best of all is utilizing the soil itself as a reservoir. 

Soil Water as a Plant Food. — All vegetable matter consists 
largely of hydrogen and oxygen, which elements are obtained 
from the soil water and combined with other elements in the 
plant itself. These combinations of the water forming elements, 
together with a small amount of carbon from the air, form by 
far the greater weight of domestic plants even when they are 
thoroughly dried. Tt is the water used as food that makes up 





the greater part of all the starch, sugar and other similar com- 
pounds so valuable, in that they form one of the essential parts 
of the foods for men and lower animals. 

Water as a Carrier of Plant Food. — All of the plant foods 
in the soil have first to be dissolved in water and then carried 
by it to and through the roots and up to the above ground parts 
of the plant. The tiny feeding roots must be immersed in the 
thin film of water that clings to the soil particles. The soil 
solution is absorbed into the rootlets through their walls and 
forced upward with a considerable pressure. This can easily 
be noticed by cutting off a rank growing weed and watching 
how quickly the sap is thrown up over the newly cut stump. 
This pressure is often several pounds per square inch. All the 
water that is not combined in the plant as a part of it is thrown 
out through the leaves, this process being called " transpira- 

If the moisture conditions of the soil are good and water is 
abundant, transpiration is encouraged and there is an attending 
satisfactory growth of crop ; but if the conditions are reversed, 
the plant growth is immediately stunted by the deficiency in the 
amount of the essential water. 

Amounts Necessary for Crops. — Taking crops altogether, 
from rice to date palms, the amount of water required varies 
from complete submergence to almost perpetual drouth, and 
within this range crops vary widely as to the amount necessary 
for living. As a rule the amount is large, as it is only the desert 
plants that thrive on a scant supply. Take a small potted plant 
and place it under a glass jar and notice how soon the jar is 
clouded by the water vapor taken up from the soil and given 
off through the leaves. From 200 to 600 pounds of water are 
transpired by ordinary crops for every pound of dry matter 
produced, but this varies with each crop according to the 
climate and other factors affecting it. 

A good yield of pea vine hay will draw 1200 to 1500 tons of 
water through its roots and stems and liberate it in the air. Corn 
and cane drew equally heavily upon the soil supply of moisture. 


The water required by a field of any of the ordinary field crops, 
if spread over the surface, would cover it to a depth of several 
inches, sometimes as much as a foot or more. This is only the 
water used by the plant itself, and does not include the amount 
that is lost by being evaporated or that passing too deep into the 
soil to be drawn back to the roots. In addition, a plant cannot 
take all of the moisture out of the soil in the range of its roots. 
In irrigated districts the amount of water applied to and 
absorbed by the soil often reaches an amount equal to three 
feet, and in some localities more. 

This water used by the plant or lost by evaporation from the 
soil during rainless days must all come from the soil, and shows 
what care must be exercised in storing and holding all that is 

Water and Soil Temperature. — A uniform soil temperature 
is essential to the best growth of crops, and a soil properly sup- 
plied with moisture will change its temperature very slowly, 
while a dry, parched soil will quickly heat up during the day and 
cool off again as rapidly at night, and the crops will suffer 
accordingly. Coarse soils retain only a relatively small amount 
of moisture and are warm and early. Fine soils, like the clays, 
retain much more water and are cooler and later in the spring. 

Storing Water. — Where irrigation is practised, reservoirs 
are used to store and hold water, but in most of the states this 
method is inadvisable. The best place to store the water for 
use in time of drouth is in the soil itself, by converting the sub- 
soil of every acre into its own reservoir. This large storage 
may be assisted and encouraged in several ways. The first thing 
to do is to be sure to get the rain water down into the soil 
instead of allowing it to be wasted by running off on the sur- 
face, because it cannot enter a hard or impacted soil readily, if 
at all. Such soils may be found to be dry even after a heavy 
rain. In " dry farming," and also in farming where the rainfall 
is heavier, some practise rough plowing before the seasons of 
heavy rain to increase the absorption of rain water, and later 
harrow or drag the surface to form a mulch and prevent loss 



U. S. Rec. Service 


through evaporation. Where this practice has been carefully 
followed, good has resulted, but ordinarily the depth to which 
plowing is possible is insufficient to reach the zone of the great- 
est trouble. Others have gone further and plowed deeper, using 
heavy tractors with subsoil plows. The results obtained have 
been variable, and it is quite evident that the efforts along this 
line, while well conceived and of benefit, have fallen short of 
their mark by not disturbing the soil to a sufficient depth. 

In most cases of resistant soils, the trouble is at a considerable 
depth, in fact, below the depth that could possibly be reached 
by any form of plow. For relief then, there is nothing prac- 
ticable but a rational use of a subsoiling explosive. This, like 
the subsoil plow, is used when the subsoil is dry, so that the 
force of the explosion will shatter and pulverize the subsoil 
rather than pack it into a more impervious mass. Usually this 
is in the late summer and early fall, when the plants have 



pumped all of the available water out of the soil. This season 
is followed by the fall and the winter rains which can then 
find their way deep into the cracks and fissures where they are 
absorbed and held indefinitely if proper care is given to the sur- 
face. The heavy rains following such a shattering of the sub- 
soil have the additional advantage of resettling any parts of 
the soil where the explosion may have opened it up too much. 
In the spring and summer following such a soil treatment, the' 
young roots find an easy path into the deeper soil, where they 
can continue to draw their full ration of water from the stored 
supply and thus nourish the crop during long seasons of drouth. 



Excesses of Water Must be Drained Away. — Field plants 
will not grow in a soil saturated with water. An ample supply 
is necessary and must be maintained, but a great deal depends 
on how the supply is kept up, or in other words, on the moisture 
condition. Land animals require water to drink, but perish if 
immersed in it, for the air necessary for their existence is then 
shut off. Plant roots die if the soil is saturated with water 
because their air is cut off. Fortunately, soil will hold only a 
certain amount of moisture if the water is free to move, the 
excess gravitating downward and draining away. This is 
called gravity of free water. The gravity water sinks until met 
and checked by impervious material or reaches standing water ; 
that is the water table. Unless such free water sinks too deep, 
it is not entirely lost to the plant, as it not only sinks through 
gravity, but is also brought back to higher levels, when the top 
soil begins to dry, by capillary attraction, just as water climbs 



up a piece of cloth, one end of which is allowed to hang in water. 
This capillary water is the water that supplies the immediate 
demands of the plant. Some of the water collects on the surface 
of each soil particle and sticks to it with a peculiar force, form- 
ing a film over the soil grain. This " Film Water " is very 
important, for the force that holds it so closely to the grains 
enables it to dissolve the mineral plant foods in the particle and 
prepare them for absorption by the roots. 

Air Must Circulate in the Soil. — The air in the soil is as 
essential to plant growth as the air above the soil. This soil 
atmosphere below the surface is heavier than the air above, and 
contains more carbon dioxide and similar compounds than our 
atmosphere. These gases are absorbed into the soil water and 
become a part of the attacking force that liberates the mineral 
foods from the dense minerals. The nitrogen supply of the 





legumes is also drawn from the soil air. This air circulates 
through voids or pores which are stopped up by excesses of 
free water that cannot drain away. Such a condition stops 
the actions just described, and must be guarded against by 
keeping free water drained away from the active feeding zone 
of the roots. When the water table is within the reach of the 
deeper roots, small feeders are sent down to or near the water 
surface and drawn from the moister soil there. 

Cultivation and Yields. — The easiest soil to plow or cultivate 
is one that has all excesses of free water drained away, and has 
dried a little so that it will crumble rather than break in lumps. 
A wet, soggy soil is not only hard to cultivate, but the very act 
of working it injures instead of being a benefit. The air is 
worked out, and the air spaces themselves are closed by the 
process, and the granulation is destroyed. A very dry soil 
breaks up cloddy, and the condition produced by plowing it 
when it is in this condition is sometimes nearly as bad as if it 
had been plowed wet. The proper storage of capillary moisture 
by good cultivation is the only safeguard to maintaining the 
proper tilth of the soil and to prevent puddling or the forma- 
tion of clods. 

The aim of the farmer is to produce crops at a profit. Water 
is the cheapest article he has to handle, and is at the same time 
one that allows itself to be handled almost at will, but becomes 
a serious drawback if allowed to take its own way. It must be 
there as a food and a carrier of other foods, as a control of 
the temperature of the soil, and to insure the proper granu- 
lation of the soil. Everything that can be done to the soil in the 
way of getting rid of excesses of free water and holding the 
maximum of capillary water will make itself known in the 
increased yields it affords. 

Erosion. — Erosion or washing steals plant food. If bad, it 
takes the whole of the surface soil away. An excess of water 
often causes damage by erosion. In addition to taking away 
valuable plant food and the cultivated top soil, erosion leaves 
the fields cut up and rough and exposes material that requires 




<tfil ■ nihil Jr.i £dt» .- 

£* ■■■ 


£7. 5. D. ^. 


much effort and long exposure to weathering before the plant 
food reaches a satisfactory state of availability. Gentle, slow 
rains are always preferable, because they have more time to 
soak into the soil, but as the intensity of rainfall is beyond the 
control of the farmer, he must fortify his soil against attacks 
of erosion due to heavy precipitation or large amounts of rain- 
fall in a short time. The answer is to get the water down into 
the soil before it can run off. It is a difficult matter to do this in 
a big wash, where thousands of barrels of water are coming 
down, but these large washes are started by little trickles of 
only a few spoonfuls further up the hill. These little trickles 
start because the soil is too tight for the water to enter. The 
surface ma}' be sealed over by a little crust or there may be 
plow sole, tight clay, or hardpan deeper down which limits the 
soils absorption to the immediate surface. The correction of 
such conditions prevents the wasting of the valuable soil into the 
drainage courses. The surface crust can be destroyed with 
even the lightest tools, and a deep shattering by blasting will 
open up the subsoil so that it will be able to absorb hundred of 
gallons of water, where before it took but sparingly. 



Clemson College S. C. Bulletin 


Drainage. — Attention has already been called to the neces- 
sity of removing all excesses of free water. Where such 
excesses are caused, as they so frequently are, by the water 
being held on or near the surface by hardpan or other imper- 
vious material below, the trouble may be overcome by breaking 
through the holding material into more open material below. 
The full extent of the possibilities of this method of drainage 
have not yet been developed, and it is quite likely that many of 
the upland swamps will later be entirely controlled by this 

A more rapid development of the larger swamp areas has 
been retarded on account of the great expense of ditch digging 
by hand or by the machines suitable for digging under such 
conditions. Again, a rational use of dynamite has answered 
the question, for it has been absolutely proven by experimenta- 
tion and practical application on large and small drainage areas 
that ditches can be quickly, economically and satisfactorily 
excavated by blasting. The wet soils of the swamps and over- 
flowed regions have made digging by hand expensive on account 
of the difficulties encountered by the labor, but swamp water has 
no terror for the swift cutting action of a high power dynamite 
that will rip open a long stretch of large or small ditch at one 
effort. Such a blast not only opens the ditch, but levels down 



the harmful spoil pile or bank, scattering the dirt over the 
adjoining land for a distance of over a hundred feet. 


Ditch blasting is by no means limited to wet lands, for it is 
being successfully used in excavating even in dry hill soil, pro- 
vided it is not sandy. Changes in the soil or the soil condition 
require changes in the selection of the explosive and the method 
of loading, which are details that can best be learned from the 
books of practical instruction of the manufacturer or from one 
of their representatives. 

The use of blasting in connection with drainage is not limited 
to the shattering of deep drainage courses to permit of down- 
ward drainage, but is being used largely in connection with 
open and blind ditches where the subsoil is so hard that it pre- 
vents the passage of the water into the drainage channels. 


Thorough subsoil blasting opens up these subsoils and permits 
the drains to collect and carry away the water that has rendered 
the fields worthless. 

Dynamite and farm powders are also being used to control 
old-established gullies or washes. The banks are shot down 
into the bottom of the gully so that teams can be driven across 
to plow the banks down to the desired level. This shattering 
also loosens deeply and increases the immediate absorption of 
water and benefits further by holding out of the surface drain- 
age much of the water that before increased the run off and 
attending erosion. 


i. What is the amount of the annual rainfall in your part of the 
state ? 

2. How is this distributed during the year ? 

3. Which of your crops suffer most from lack of water ? Why? 

4. Describe your ideal method of storing water on your farm 

for the use of crops? 

5. What have been your experiences with deep plowing? 

6. What is your method of controlling erosion, and what results 

have you obtained? 

7. What modifications in your practice of controlling erosion 

do you think necessary? 

8. Describe an ideal plan for the general drainage of your 

farm, that will include the control of the hill water as well 
as that of the bottoms. 

9. What is the best method of correcting a small stream that 

has a crooked, shallow bed? 



Soil Bacteria 

The most constantly active part of the soil is its bacterial life. 
These are tiny little plants that are very close to the border line 
of being animals, and are known by a number of popular and 
slang names. They are the smallest known living organisms. 
Some are so small that 50,000 of them lying side by side would 
not measure over an inch, and a single drop of blood or milk 
would form a desirable tenement for thousands to live in and 
multiply. They reproduce very rapidly, usually in from 15 to 
45 minutes. If unchecked, a single bacterium could multiply 
to 17,000,000 in 24 hours. This reproduction is seriously 
checked by lack of room, insufficient food and unfavorable sur- 
roundings, such as lack of air or too much water for some 
and the reverse for others. They are also checked in their 
development by the presence of their own excreta. They form 
spores for their reproduction and for preservation and distribu- 
tion. In the spore stage they can live over long periods of con- 
ditions unfavorable for their growth and reproduction, and 
then begin their work again when conditions are favorable. 
The total number of bacteria is inconceivable, for they are in 
the air, water, soil, and everywhere. 

Some of them are harmful, and their development should be 
checked, while others are so helpful to mankind that every effort 
should be made to encourage their growth. The different 
forms require widely different conditions for their best growth. 
One class thrives in an abundant supply of air, and are called 
" aerobic." Another form, " anaerobic," get their oxygen from 



different forms of bacteria 
(greatly enlarged) 

breaking down compounds containing this element and thrive 
best in places that are not well ventilated. The first named 

form includes the beneficial 
forms of soil organisms, while 
those of the second class are 
usually harmful. The very 
cultivation and aeration of the 
soil, therefore, promotes the 
growth of the beneficial forms 
and checks the activities of the 
harmful ones. The deeper the 
soil is loose and well aerated, 
the deeper the helpful forms 
are found. 

Harmful Bacteria. — Some 
forms of bacteria produce de- 
structive diseases in the plants, 
both in the tops and branches and in the roots. The greatest 
trouble from bacteria in the soil, however, comes from the 
forms that attack the nitrogen carrying foods and cause the 
nitrogen to be unlocked from its combined form and to escape 
as gas. These forms thrive best in wet and packed soil, 
where they cause the organic substances to undergo a waste- 
ful putrefaction rather than a beneficial decay. Their ac- 
tivities are at once checked by the presence of free air. Some 
crops grown continuously on the same soil for a long time 
cause it to become filled with forms that cause diseases in the 
roots. Generally these can be destroyed by a rotation of 
crops attended with deep tillage. 

In short the control of harmful soil organism is accom- 
plished by thorough drainage and good, deep cultivation. Many 
of them seem to thrive best in sour soils which can be made 
sweet and desirable for the beneficial forms by additions of lime. 

Beneficial Organisms. — Bacterial action is beneficial to 
agriculture in many ways. As soon as a plant or animal dies, 
the influences that have restrained the action of the organisms 
of decay are removed and the bacteria at once begin breaking 



down the complex organic substances into forms that are 
again suitable for plant food. In this way they are the health 
patrol, the scavengers of the soil. Some forms have the power 
of liberating food from the insoluble mineral soil grains and 
are the fairy chemists whose laboratory is the surface of the 
soil particles. These soil builders have already been described 
elsewhere is these articles. 

In fact there are millions of these tiny forms that are eager 
and willing to assist the farmer and gardener if given proper 
soil atmosphere, proper soil moisture, and proper soil temper- 

Nitrogen Fixing Bacteria. — Attention has been called to the 
likelihood of a deficiency of nitrogen in the soil and the high 
cost of replenishing the supply through the use of expensive 
fertilizing materials. Certain of the air-loving bacteria form 
little colonies, called nodules, on the roots of leguminous plants 
and take the free gaseous nitrogen of the soil air and tie it up 
in compounds that furnish the nitrogen fertilizer to the higher 
forms of plants. These 
bacteria do not thrive in 
either a wet or a sour soil, 
and are not found naturally 
in the soils of many parts 
of the country. They can 
be planted or started in 
such soils by the use of 
certain commercial cul- 
tures, or by additions of 
soil in which they are 
known to be present. Abun- 
dant supplies of these bac- 
teria are necessary in the 
soil before it is possible to 
get a good growth of the 
most beneficial legumes 
without robbing the soil of 
the supply of nitrogen al- 




ready present in a properly combined form. Even in soils rich in 
nitrogen the growth of these crops is materially benefited by the 
presence of the bacteria. 

Other forms of bacteria and kindred plants of microscopic 
size have the power of gathering bacteria from the soil air and 
their development should also be encouraged. These forms are 
not so well known as those that produce the nodules on the 
roots, but their benefits are marked. They demand a well 
drained and well aerated soil. 

Helping a Friend Along. — Aside from the nodule forming 
bacteria, most of the other beneficial forms are found in all 
normal soils. It is not necessary to add them in artificial cult- 
ures, but their activities can be materially increased by keeping 
them in suitable surroundings and supplying their constant but 
simple desires. These forms get their oxygen from the air, 
and must therefore not be closed up in a tightly sealed soil. 
They do not thrive in the deep subsoil unless it is well aerated. 
Large excesses of water that clog up the pores of the soil also 




exclude the air and smother out the good forms, but permit the 
harmful bacteria to grow at will. While too much water is 
bad for them, too little water also retards their work. A good 
moist soil, just about what the plants want, is their favorite 
— in short, a well drained soil. Most of them need a supply of 
organic matter, such as partly decayed plants or animals. This 
is also just what the plants want. Another one of their desires 
is for even tempered soil, where the changes are not too sudden 
from hot to cold. Here again they agree absolutely with the 
plants. In fact the beneficial bacteria and plants seem to be 
such good friends and neighbors that anything that benefits one 
equally benefits the other, and if one feels sick, the other wants 
the doctor also. 

In keeping up the bacterial activities care in turning under 
green manures or additions of litter or manure is always repaid 
many fold. These additions of humus forming material also 
assist greatly in maintaining the needed moisture supply as 
humus has a wonderful power of absorbing and holding water 
and also assists in granulating the soil. 

More About Nitrogen. — Free nitrogen is everywhere. The 
air over a single acre contains about 75,000,000 pounds of this 
peculiar element. To buy a pound will cost from 15 to 20 cents. 



The farmer, through his good little friends, the " bugs," traps 
and stores this in his soil, provided he goes about it in a business- 
like way. 

This way is simple. Prepare the soil for the best content of 
moisture and air, and see that it is not sour. Be sure that the 
right bacteria are present, and then grow deep rooted legumes 
that suit the locality best. Selections of legumes can be made 
for practically any purpose. Some of them yield the most 
nutritious hay, while others furnish grain that is good for food 
for both man and all kinds of farm animals. Others furnish 
excellent pasture. Some are best suited for soil building in the 
shape of green manure. 

The deeper the preparation of the soil the better the results 
that are obtained. A few inches of loose soil will give just so 
much room for these activities. A few inches more will be of 
benefit, but the desired production cannot be reached until the 
air-loving bacteria and the deep-rooted plants have several feet 
of good mellow soil in which to operate. The only satisfactory 
method of effecting such deep tillage is by blasting. 



i. Are the changes due to the rotting of a plant or animal under 
water the same as rotting in the air ? 

2. What are the most noticeable differences you have detected 

in the two kinds of rotting? 

3. What are five beneficial effects of bacteria on the farm ? 

4. What are five harmful effects of bacteria on the farm ? 

5. How would you prepare a bottom having a cold, wet subsoil, 

and drained by a deep open ditch, for growing ordinary 
field crops ? 

6. How would you prepare a tight hillside subsoil, low in lime, 

for growing alfalfa? 



The Movement of Moisture and the 
Feeding Zone of Roots 

The movement of moisture in the soil is of the utmost impor- 
tance to plants. It is first necessary that the water received/ 
from rain or irrigation should move downward through the 
soil, leaving behind only such as is held by capillary attraction. 
The excess should move out of the soil and into the drainage. 
This movement of moisture is entirely one of gravity. Water 
moving in this way is called " free water." 

Movement of Water by Gravity. — In order to get the water 
down into the subsoil and prevent its running away as surface 
drainage, or standing on the surface and stopping all possi- 
bilities of air circulation through the soil pores, it is essential 
that it move downward very soon after it is deposited on the 
surface. This movement depends on the openness of the soil. 
Sometimes in a sandy soil the water soaks into the soil too 
rapidly and too much drains away, but such is not the case with 
clay and other dense soils. In such soils the pores are naturally 
small and the water is held back. The movement can be 
hastened by tilling or stirring the soil to the depth to which it 
is desirable to carry the water. The deeper this can be made 
effective the better, and so it is very apparent that soils where 
the water is likely to stand on the surface ace in need of the 
deepest practical tillage. As the free water clogs the pores and 
stops many of the soil processes, the plants do not draw their 
moisture from it, but get it instead from the smaller capillary 
supply left behind. 



Movement of Capillary Water. — The capillary or film move- 
ment of moisture takes place in all directions, but its most 
important direction is upward. When tight soils prevent the 
downward percolation of free water, some is carried downward 
by this pull which has been described elsewhere as the same 
movement as the oil moving in a wick. As the amount of moist- 



ure that is held by capillarity is limited and if not replenished, 
the supply within reach of the roots may soon be exhausted. 
This available supply is partially maintained by the upward 
movement of capillary water. As one point becomes dry, the 
water is drawn from below by a constant pull on the thin film. 
When capillary water moves from the more abundant supply 
below, it brings with it soluble plant foods to assist in nourish- 
ing the plant. 

The movement of capillary water is effected by several con- 
ditions. It is governed very largely by the texture of the soil. 
The finer the soil and the more surface the soil particles expose, 
and the more points of contact between the particles, the greater 
is the pull. For example, a heavy clay soil containing 20 per 
cent, of moisture may draw water from a coarse sand contain- 
ing only 10 per cent. Sandy or coarse soils move water very 
rapidly and in large amounts, but the movement in such soils 
cannot take place over long distances. With clay, which has a 



much stronger capillary pull, the movement is much slower, 
but may take place over greater distances against gravity. The 
amount of moisture moved in this way decreases as the limit 
of distance is reached. 

In addition to the texture, the structure of a soil has an im- 
portant part in governing the capillary movement. The better 
granulated a heavy soil, the greater the pore space and conse- 
quently the greater the pull. Additions of humus materially 
increase the capillary pull as well as the reservoir capacity of a 
soil. In a puddled soil the movement is very slow and the 
amount of water moved very small. The denser the soil be- 
comes, the slower the movement. 

Dry layers of soil break off the capillary pull on account of 
the coating of the soil particles being of _______„_ 

such a nature that they resist wetting. It 
is this fact that makes the effectiveness of a 
dry dust mulch, in holding the water below 
the surface and not allowing it to rise to the 
surface and be lost by evaporation. Capil- 
lary movement is much faster in wet or 
moist soils than in dry ones, so it is advis- 
able at all times to preserve some moisture 
in the soil if only for its benefits in a rapid the capillary 
equalization of the moisture content when rise of moisture 
water is applied. The ratio of the move- checked by a 
ment in wet and dry soils has been shown dust mulch 
to be as high as i to 4. 

This upward movement continues to the surface and when 
allowed to go unchecked will result in all the movable moisture 
being pulled up and lost by evaporation. The rate of evapora- 
tion of moisture from the surface is governed largely by tem- 
perature and wind velocity. When water is stored at great 
depths in the soil it is harder for it to be pulled to the surface 
and lost. This surface less at times approximates an amount 
equal to a sheet of water 5 inches deep, over the whole surface 
in a month. A handy example of the upward movement of 
water and a check to its loss can be observed by turning over an 



old log or plank that is lying on the ground and noticing the 
large amount of water in the soil immediately underneath. 

The Feeding Zone of Roots. — The root systems of plants 
require as ample room in which to develop as does the stalk and 
leaf system above. Roots must both anchor the plant in place 
and reach down for food and water. The feeding zone of a 
plant determines the amount and value of the top. The soil 
must be cultivated in order to provide a proper feeding zone, 
for the earth in its natural condition will not yield as abundantly 
as well cultivated soil. Just below a good surface mulch in a 

well cultivated field we find 
moist soil full of roots revel- 
ling in an ideal feeding zone. 
On an adjoining uncultivated 
field one must dig down to find 
moist soil, and discovers only 
a few roots feeding in a mea- 
ger compact feeding zone. 
Rootlets are ever pushing into 
fresh soil zones where more 
water and food are to be 
found, yet the feeding zone 
in ordinary farming is con- 
fined largely to the shallow 
depths of the plowed furrow, 
simply because it is the only 
warm, mellow, well ventilated 
soil within the reach of the 
roots. When given a chance, 
feeding roots advance rapidly 
lo meet the capillary rise of soil moisture, and the energetic 
way in which they go down and search in every direction for 
food and water proves them to be highly organized parts of 
the plant and possessed of instinct or something akin to intelli- 
gence. Plants having large or active root systems, making 
a rapid growth, remove more water and more plant food from 
the soil in a given time than those with a small system or 


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sluggish action. A corn crop when in the season of most 
vigorous growth will remove more water from the soil in 
a day than will a crop of wheat. Some crops are slow, weak 
feeders, while others feed ravenously, and, while taking up 
more substance, may be able to overcome more unfavorable 
conditions. Roots should be thrown down into the soil as far as 
possible in order to get away from danger of drouth, and 
excesses of temperature, as well as from injury by cultivating 

The desirable conditions for a root system can be improved 
by thorough cultivation of the subsoil, much deeper than any 
plow can go, by means of explosives. ■ They loosen up the soils 
so that the roots are not checked in going downward, the rise of 
capillary water is aided, aeration is improved, and deep reser- 
voirs of water made accessible. This method more than doubles 
the depth of the feeding zone. 

Depths to Which Roots Go. — The natural tendency of most 
roots is to go deep into the soil. Many who have not investi- 
gated this subject believe that roots do not go deeper than one 
or two feet and cutivate accordingly. On the contrary, they go 
to much greater depths if the soil conditions permit. Corn 
roots that have been confined and have occupied all the soil to a 
depth of 2 feet, will go to a depth of 8 feet if the restriction is 
removed. Wheat, oats and barley will penetrate from 8 to io 
feet, grass roots will go down 6 and 8 feet, while alfalfa has 
been known to go down over 30 feet. Grapevine roots have 
been found 22 feet below the surface, while the root systems 
of trees correspond in extent and branching to the parts above 
ground. The roots of clover weigh as much as the total weight 
of the year's crops, while the roots of an oat crop are nearly 
50 per cent, of the weight of the seed and straw. The total 
length of all the roots of a wheat plant was found to be about 
268 feet, of one rye plant 385 feet, and of one corn plant 
1452 feet. Such facts show that the size and depth of the root 
systems are generally not appreciated, and are generally under- 
estimated. It is evident that the roots need a far deeper feeding 



Courtesy Prof. Ten Eyck, Kas. Expt. Sta. 


zone than is ordinarily given them. The feeding zone has been 
shallow and meager, largely because the farmer could formerly 
find no suitable means for the deep cultivation. No practical 
machinery can till the soil as deep as 2 feet, and even that limit 
is not sufficient for the needs of crops. Such deep cultivation 
is possible only with high explosives. 

The benefits of deep rooting of a crop do not pass away when 
the crop is harvested, for the roots are left down where they 
grew, and on decaying form humus at a depth where it would 
be impossible to place it by artificial means, down where it 
will help to perpetuate the granulated condition of the subsoil, 
and keep alive the deep feeding and working bacteria, helping 
the farmer to gain thereby the full return from all of his field 
rather than from the top only. 



Weeds and Their Effects. — Weeds injure crops by robbing 
them of their water and food. The escape of water is intangi- 
ble, like the setting free of plant food, because we cannot see 
either with the eye and must put our wits to work to detect its 
departure. Weeds may have a mission in life ; anyway they are 


stimulating rascals. When the farmer gets mad enough to go 
after them, their mission is ended, for by destroying them he 
conserves the moisture by unconsciously cultivating the ground 
and increases the fertility of the soil. 

Conserving the. Moisture. — Where the moisture supply is 
deficient, weeds should not be allowed at any time before, 
during, or after the crops, for they remove water from the 
soil as rapidly as the useful plants. When the water is ample, 
but the soil too fine to permit rapid enough capillary movement, 


green manure should be grown and plowed under deeply. The 
chief feature in conserving moisture is, of course, to get the 
moisture in hand. This can only be done by leading it down 
into the soil to great depths. If the soil is of such a nature that 
this takes place of its own accord, all well and good, but many 
soils are not that way. They are stubborn, and need a real first- 
class shooting with an explosive to subdue them. Then the 
maintenance of the organic matter and surface mulch can reach 
their desired effects. 


i. What soil conditions cause water to be held on the surface of 

2. Will oil rise faster in a moist or dry lamp wick ? Will the 

same principle always hold true of soils? 

3. Why does a dry layer of soil stop the capillary rise of 

moisture ? 

4. When should a dust mulch be renewed ? 

5. What effect would a few inches of loose straw on the surface 

have on the soil moisture during a rain ? During hot, dry 
weather ? 

6. Why is it beneficial to fall plow and deep till thin, hard 

lands and cover the surface with trash? 

7. Which will you find at greater depths, wheat or clover 

roots ? 




Cultivation — Use of Explosives 

The present means and methods of cultivation are behind 
the times. They are not up to date with the progress made all 
along other lines. They all work too shallow, cultivating the 
land a few inches where they should loosen and stir to a depth 
of several feet. A world of wealth in thought, money, inven- 
tion and machinery has been bestowed upon the first few inches 
of the soil at the surface, but up-to-date agriculture demands 
that the depths of the soil be considered also. It is not enough 
to just scratch the surface and leave untouched the storehouse 
of wealth below. 

A World of Tools. — The farmer has at his command for 
working this thin skin of the surface inches a wonderful array 
of tools. He has plows of all kinds and qualities to select from 
to fit every surface condition imaginable — hillside, landside, 
hinge, and swivel plows — equipped with every shape of mold- 
board, and coulters that may be fin, knife or rocking. He may 
use hand, sulky, or motor plows, and work them single, double, 
or in gangs. He has harrows without number, home-made and 
latest patent, coulter, spring, chain, slicing, spading and cuta- 
way, all of them equipped with teeth set vertical or set slanting, 
with plain, twisted, shovel, coulter, spike, and spring teeth in a 
bewildering dental display. He has cultivators of all sorts and 
breeds — hand, walking, and riding. He has drags, rollers, 
plankers, floats, boats, clod crushers, pulverizers, and smooth- 
ers, and he has so-called subsoilers in good variety that work 
only a few inches deeper than the tools already mentioned. 



Yet with all this to select from he can do but little better than 
the Romans did — prepare the seed beds and scratch the surface, 
while at greater depth the roots still have to scratch for them- 
selves, as they did centuries ago. It is too much on the prin- 
ciple of the man who only greased the front wheels of his 
wagon, saying that if they went the hind ones would " just 
naturally have to follow." 

Progress Demanded. — With lands becoming scarce and 
prices higher, there is a demand for methods that are more 
efficient, that will cultivate the ground to greater depths, that 
will meet the demands of the feeding roots, that will double the 
■feeding zone, that will furnish deep moisture reservoirs, that 
will extend bacterial activity downward, that will double and 
treble the farmer's acreage of productive soil by depth, and not 
by area. So far as these demands are concerned, farm machin- 
ery is so far a failure and but little advance has been made on 
the primitive plow, the sharp stick with a V-branch. It is not 



enough to secure ease of draft, of raise heavier and faster - 
walking horses. It is not enough that the ox, horse and mule 
are giving way to steam, gasoline, and electricity, to cable 
traction and automobile luxury. It is not enough to point with 
pride from the one-negro-one-mule-one-plow combination to the 
monster steam gang plows. Something more is demanded. 
The present machinery is good so far as it goes, and is the best 
that the world has ever seen until recently, but it does not go far 
enough. It does not go down. Many remedies have been sug- 
gested only to meet with a cold reception. It is always difficult 
to change old conditions, old customs, for there is ever prejudice 
against such changes. The kind of prejudice that the first cast 
iron plows (Newbolds, 1797) " poisoned the land " and " caused 
weeds to grow " is still in existence, and can only be overcome 
by enlightenment. 



Shallow Methods Prevail. — All methods and machinery in 
common use are good for preparing the seed bed, but are of 
little or no use in helping the roots to go down to their natural 
length; of no use in improving the soil atmosphere more than a 
foot or two, or in meeting the many and varied demands of the 
plant system below the surface. The function of the plow is 
essentially to turn a thin ribbon of the soil on edge or upside 
down, and to shatter and break the surface of the earth as much 
as possible, and to destroy weeds, and bury refuse. Harrows 
and cultivators have primarily a stirring action that forms 
mulches and prevents surface evaporation, but they work at 
even shallower depths than the plow. Some of the instruments 
used tend to form plow sole, or hardpan and impacted con- 
ditions of the soil close to the surface, defeating the very object 
of cultivation. 



The most, effective of all farm tools in breaking up the sur- 
face soil is the plow, and its use in working up a tight surface 
soil into a satisfactory condition of tilth must never be over- 
looked. The effectiveness of the plow has been improved by 
using modifications that will disturb the soil to greater depths 
than is possible with an ordinary moldboard plow. The best 

known tool of this type is the 
narrow subsoil plow that fol- 
lows along in the freshly 
turned furrow of the regular 
plow, deepening the cultiva- 
tion several inches. Such a 
plow does not bring the sub- 
soil to the surface but simply 
stirs the subsoil. The depth reached is seldom as much as 18 
inches and is usually not more than 12 to 14 inches. A more 
improved implement is the new double disc Spaulding Deep 
Tilling Machine, which combines in one tool both the surface 





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and the sub-surface plow. One heavy disc follows behind 
and below another, and by their cutting, twisting action 
break and mix the surface soil with a layer of the material 
lying underneath. Excellent results have been obtained with 
both forms of deep plows, and their use is strongly recom- 
mended, as their immediate action is to break up the plow sole 
or shallowest hardpan material. They also leave the surface 
and immediate sub-surface in a most desirable condition to 
receive the rain water and allow it to be conducted to the deeper 
subsoil that has been shattered with an explosive, where it may 
be held by capillary absorption. 

Benefit of Using Explosives. — It is admitted that present 
methods of cultivation do not go deep enough, and it must also 
be admitted that the use of specially prepared agricultural 
explosives offers the desired remedy. It is admitted by all 








authorities in agriculture that the plow and harrows do not 
go deep enough and they advise the use of subsoilers. Scores 
of books explain how and why each piece of machinery turns 
over the soil, reduces it to fineness, forms mulches, saves water, 
breaks clods, aerates, stimulates bacteria, etc. If all this wealth 
of invention and labor is worth while bestowing upon the first 
few inches of the soil why it is not worth following the roots 


down to their second foot of growth, their third, and even their 
eighth and tenth foot when they flourish at those depths. The 
only reply is, " Yes it would pay, but how can it be done? ". It 
can be done economically, quickly, and thoroughly by the use of 
explosives. Deep plowing is recommended by all authorities 
" wherever the resisting soil will permit." Machinery made 
especially for deep work may be stopped, but nothing can 
resist the explosives. The farmer plows, harrows, and spends 
time, labor and money in cultivating the surface foot and re- 
joices in the wonderful alchemy that follows his endeavors — the 
mysterious activities he has set in motion. He works cheerfully 
and with confidence, largely because he can see what he is doing. 
In the new agriculture he must work by faith and reason in 
depths where he cannot see with his eyes what is taking place. 
The result will place before his eyes in the form of bumper crops 
proofs of the benefits of his work. The new agriculture simply 
points out the benefits acquired by the thorough cultivation of 
the foot, or two feet, and by explaining how and why this is 
accomplished, points out the value of extending the cultivation 
further down by the simple means of explosives. The harrow 
warms and aerates the soil and promotes activity by loosening 
and separating the soil particles at the surface. Explosives do 
the same, breaking, loosening, pulverizing at depths machinery 
cannot reach. Drainage is recommended by all because it 
removes excess of water, admits air, and gives proper moisture 
conditions. Explosives have drained many a field and secured 
all these benefits at far less cost in time, labor and money than 
the usual methods of ditching and tilling. 

The importance- of nitrification is proven, but why confine it 
to the thin furrow slice when the action of bacteria has been 
proven at depths of 6 feet in the humid soils of the East, and 
still deeper in the porous soils of the arid and semi-arid regions 
of the West? Why not loosen the soil and secure proper condi- 
tions by the use of some charges of explosives? It is admitted 
that there is much of plant food below the shallow plowed and 
cultivated ground, and that the roots will go down if they can. 
Why not open the way and make it easy for them by cracking 



and pulverizing the soil with explosives as far down as the roots 
care to go ? It is admitted that water may be stored, as in dry 
farming, by converting the soil itself into a reservoir by making 
it porous so that it absorbs^ water and holds it like a sponge. 
Why not use explosives and make the reservoirs two and three 
times as great and secure absolute instead of partial insurance 
against drouth? 

It is admitted that much of the rainfall is lost by running off, 
and consequent damage done by erosion. Why not check this 
by the use of explosives before the rainy season, storing the 
rainfall in porous soil instead of letting it run to waste? It 
is admitted that some of the 
soils called " wornout," or 
" poisoned " and " worthless " 
may be reclaimed if the soil is 
thoroughly stirred up from the 
depths. What can do this so 
efficiently as explosives ? It is 
admitted that much of the 
plant food in the soil is una- 
vailable because it is un- 
weathered. Why not make it 
available by opening the 
ground to weathering agencies 
by explosives? 

The benefits of clean sum- 
mer following every other 
crop, under low rainfall, and 
occasionally under abundant 
rainfall are admitted. Why 
not secure these benefits by 
means of explosives? It is 
admitted that granulation of 
a soil is a benefit, that any 

treatment that increases the lines of weakness in the soil 
structure facilitates the movement of capillary water, and the 
action of moisture films. The more numerous the lines of 
weakness the quicker granulation is secured. 




The fewer the lines of weakness the more close and cloddy 
the structure. What will granulate soil to the depths quicker 
than explosives? It is admitted that present machinery can 
only increase the feeding zone of the roots an inch or two. 
What can explosives do in this line? A cubic yard of hard soil 
has 6 faces and 9 square feet in each face, or a total of 54 square 
feet. Divide it into 1 foot cubes and there are 162 feet of 
surface. Break it into inch cubes and it presents 1944 square 
feet, or nearly 1/20 of an acre of feeding surface for the roots. 

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A single cartridge of explosive can easily convert several yards 
of compact and useless hardpan into half an acre of new feed- 
ing ground. Costly, massive, improved machinery enables the 
farmer to spread out his operation, to move horizontally, and 
handle more acreage in the same time, and he is ever eager to 
double and treble his holdings of fertile soil. What is wanted 
is something that enables him to move vertically down and 
double his acreage, and double his yield by doubling the fer- 
tility of the soil, by doubling the depth of the feeding zone, by 


doubling the water supply, by cultivating the ground to double 
and treble the former depths. " Vertical Farming," to coin a 
name, is the keynote of a new agriculture that has come to stay, 
for inexpensive explosives enable the farmer to farm deeper, to 
go down to increase his acreage, and to secure larger crops. 
Instead of spreading out over more land he concentrates on less 
land and becomes an intensive rather than an extensive agri- 
culturist, and soon learns that it is more profitable to double the 
depth of his fertile land than to double the area of his holdings, 
and he learns that his best aid and servant in this work is a good 
explosive. Peace congresses demand that swords be turned into 
pruning hooks. The farmer is busy turning explosives from 
war to agriculture, from death dealing to life giving work. 

There is a demand to-day for farmers who think, and who 
think long and closely as well as observe; for men who reject 
nothing because it is an innovation, because it is new. Men 
are wanted everywhere who have thought for themselves how 
soil first came into being and what its form and character are 
and what they mean ; men who are not satisfied until they know 
how plants feed, where they feed, and the nature of their food : 
men who look below the surface of the ground and realize that 
as much of their future crop is there as will be above the sur- 
face, that plant roots must have air and water at the right 
times and in the right abundance as much as the animals in their 

This kind of men have been and are using explosives freely 
as the best and simplest means of securing success and accom- 
plishing their object. Their success may be duplicated by all 
who care to do so. The use of explosives for deep cultivating 
and other farm purposes has come to stay. 

Vertical farming with explosives is another step forward 
as truly as irrigation and dry farming, and is greater, for unlike 
them it is not limited to any area or region but may be practised 
everywhere and anywhere. It has the world for its field. 



1. What is your investment in tools per acre of land tilled? 

2. What is your total cost of preparing, seeding, cultivating, 

and harvesting one acre of money crop? 

3. What improvements over the practices of your father have 

you made in the use of field machinery and supplies? 

4. How deep do you actually plow? (Measure the depth at 

the unbroken side of the furrow.) 

5. Did you ever follow up the full development of the roots of 

a tree or a field plant ? What did you find ? 

6. Have you any actual knowledge of the character of your 

subsoil ? 

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