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UNITED STATES DEPARTMENT Of! iu bf Dy

Washioston, D.C. | v January 22, 1924

FIELD EXPERIMENTS WITH ATMOSPHERIC-NITROGEN
FERTILIZERS

.
By
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F. E. ALLISON and J. M. BRAHAM, of the Fixed-Nitrogen Research a
Laboratory, and J. E. McMURTREY, Jr., of the Bureau of Plant Industry
pee
Pa
CONTENTS f
Page Page i
SN sg he ee ae a 1 Observations During Growth. ...... 6 e ory
Dempepememieierd: 2.0) ei bee oe a ee Gs 2 Experimental Results ........... 10
Sinds ami@weng 2 tudes relist ig oliclie le (ev 5 Review of the Results. .........-. 39
Methods Used in Experiments ....... 5 Summary 6275S ss tee ean eee 41
\
WASHINGTON
GOVERNMENT PRINTING OFFICE
1924

Washington, D. C. v January 22, 1924

FIELD EXPERIMENTS WITH ATMOSPHERIC-NITROGEN FERTILIZERS.’

By F. E. Atzison and J. M. Branam, of the Fixed-Nitrogen Research Laboratory, and
J. E. McMurtrey, jr., of the Bureau of Plant Industry.

> CONTENTS.

Page. Page.
oT TEC a Sa ee eee ae 1 | Observations during growth—Continued.
EEL Re eee eer 2 ‘Ammonium ehidnd !; 2/2. 224 2e- 9
STRESS ee ne 5 OTC os Sata - aye bob 2 ov 5 smo g-- 585 --eseP g
Methods used in experiments. ......-...----- 5 WEGPHOS.« < .o8 oo ae San won nen =e obpe eee 10
Observations during growth................- 6 } Experimental results... .. 22.2.0... 22.00.2028 10

(MAT ee ae: ee 7 Experiments 0f 49194. 25... ea uae 10
Ammonium nitrate, double salt, and Experiments of 1920 and 1921............ 18
Ph Ss ee ee 8 | Review of he TOSGHS: ~.ccgcahewseesss.wadaee 39
Ammonium phosphate and ammoniated BHIBMUNS U feet cannes ea suaumemadescapenetean 41
Sepprpmoninate. =: Sse St So 9
INTRODUCTION.

Nitrogen compounds made from the air are rapidly becoming im-
portant in meeting the world’s constantly increasing demand for
nitrogen fertilizers. A number of Kuropean countries are already
Seeger ig sufficient atmospheric-nitrogen fertilizer to meet the
larger part of their requirements. The United States has made a
beginning in this direction but still depends almost wholly for her
nitrogen upon the natural sodium-nitrate deposits of Chile, the
ammonium sulphate obtained from by-product coke ovens, and the
various organic sources, such as slaughterhouse wastes, cottonseed
meal, and fish scrap. A small quantity of cyanamid,? imported from
Canada, is also used.

Interest in the production of synthetic nitrogen compounds in the
United States was greatly stimulated during the World War in con-
nection with the production of explosives. Nitrogen-fixation activi-

1 The experimental work described in this bulletin was carried out by the Nitrate Division of the Ord-
nance Office, United States Department of War, workingin cooperation with the Bureau of Plant Industry
of the United States Department of Agriculture. The work during the first year was under the direct
supervision of the bureau mentioned. During the two following years the work was conducted by the
Fixed-Nitrogen Research Laboratory, which was a part of the Nitrate Division until its transfer to the
Department of Agriculture on July 1, 1921. The writers are indebted to Drs. Karl F. Kellerman, W. W.
Garner, Oswald Schreiner, and J. J. Skinner, of the Bureau of Plant Industry, for many valuable sugges-
tions in planning this investigation and to members of the staff of the Nitrate Division, particularly Lieut.
Cols. J. K. Clement and Hardee Chambliss, for assistance in carrying out these experiments. The Office
of Soil-Fertility Investigations, Bureau of Plant Industry, is conducting field experiments with most of
the nitrogen materials mentioned in this bulletin. These experiments have been in progress in several
States for a number of years, and the results are to appear in a Jater publication.

3 Crude calcium cyanamid treated with a small quantity of water and of oil.

§2765°—24— Bull. 1180——_1

2 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

ties during that period were largely limited to the Government, and
as a part of the program for providing an adequate supply of explo-
sives the War Department constructed two nitrogen-fixation plants
at Muscle Shoals and Sheffield, Ala., in 1917 and 1918. While these
plants were constructed for the immediate purpose of furnishing
explosives it was expected that they would be utilized for the pro-
duction of nitrogen fertilizer in peace times. Although not operating,
they represent a potential source of about 48,000 tons of fixed nitro-
gen per annum. This quantity of nitrogen is equivalent to about
240,000 tons of ammonium sulphate or 308,000 tons of sodium nitrate
and is approximately equal to 30 per cent of the nitrogen consumed
as fertilizer in this country in 1919. ‘These plants were designed to
produce ammonium nitrate for high explosives as their final product,
with calcium cyanamid, ammonia, and nitric acid as intermediate
products.

At the close of the war the problem of utilizing these nitrogen-
fixation plants for the production of nitrogen fertilizer arose, and this
immediately raised the question of the fertilizing value of the pro-
ducts which might be made there. The direct product of the larger
and more important of the two plants is calclum cyanamid, from
which ammonia can be readily obtained, and this, in turn, can be
oxidized to form nitric acid. This one plant, therefore, provides a
source of cyanamid nitrogen, ammonia nitrogen, and nitrate nitrogen,
representing all the forms of fixed nitrogen obtainable by the present
fixation processes, and hence the problem of its agricultural utiliza-
tion involves a consideration of the fertilizing value of cyanamid and
various ammonium and nitrate compounds. Considerable investi-
gational work, particularly on cyanamid, has been reported by a
number of European experiment stations, but with the exception of
cyanamid these new materials have been studied very little under
American conditions. It was to obtain information concerning their
fertilizing value that the field experiments described in this bulletin
were made.

The experiments were begun in the spring of 1919 by the Nitrate
Division of the Ordnance Office, United States Department of War,
in which the Government’s fixed-nitrogen activities were then
centered, working in cooperation with the Bureau of Plant Industry
of the United States Department of Agriculture. The work was
conducted on the reservations at the two nitrate plants, where the
necessary land, labor, and equipment were available, and covered a
period of three years, at the end of which time it was discontinued.
During the first summer the experiments dealt wholly with cyanamid
and ammonium nitrate, but the following two years the scope of the
work was enlarged to include a number of other synthetic-nitrogen
products which appeared to have fertilizer possibilities.

FERTILIZERS USED.

Experiments were made with the following nitrogen materials:
Cyanamid, ammonium nitrate, ammonium phosphate, ammoniated
superphosphate, ammonium chlorid, a double salt consisting of
ammonium nitrate and ammonium sulphate, a mixed salt obtamed
from ammonium nitrate and potassium chlorid, a mixed salt obtained
from ammonium nitrate and potassium sulphate, urea, and Ure-

‘ ATMOSPHERIC-NITROGEN FERTILIZERS. 3
phos. Sodium nitrate and ammonium sulphate, the present
standard inorganic-nitrogen fertilizer materials, were used as ref-
erence substances. In connection with the experiments on cyana-
mid a few tests were made with calcium nitrate alone and in admix-
ture with cyanamid and also tests on calcined phosphate and basic
slag as sources of phosphorus.
The composition of the fertilizer materials used, although varying
slightly from year to year, is quite accurately expressed in Table 1.
Some of the more important features of these materials which have
a bearing on their utility as fertilizers, particularly from the stand-
point of production, are briefly discussed in the following pages.

TABLE 1.—Composition of fertilizers used.

Composition (per cent).

Fertilizer. p$iisS ae ese See
NHs. P2 O3. K2 O.

Cyanamid (hydrated-.and oiled).:.. :2o222.4eso4.... 252k bess ae yes. oe 2208 WCE Ls. SE SSR TLE EE
PETISMACIMITTIETIOLALS (PTRINIOG)= = . uo do gan won no Se one hn eee asec estes BU De op Bo RR See eee
reremapiine elmOria: AE C5 Ssh et. TSE Shhh. So 4s. ee ee a. S104). 22 A teal soe tate
PA PEACNIERITE TOTES oS ht Sepa Sass = <Pp eee eee = <4 <3 20.94 |... Sb eetcul eee, = agree
Ammonium phosphate (mainly NH, He PO4).....-........--.....------- 13.9 SEO ne coe
Ammoniated superphosphate... -.. . 5.0. 525 oe wine eee se ene esse ease eee 5.4 1375: (TS. Bo tH
ie Ae eigen spas: a ise aie eee ee eee me 2 7 Oc = a) ee eS ae
Sree ree eee ee LO eee Eek bie) Oe. AA 7.0 314, 45 2 st
Calera teeee (prained nnd Coated)-~....... 2.2.2.2 5 cence neces ene ceee 14.9 |... ssentettles saade
ieee eSEAERPIEIN Se ee sa Serre rs noe Sine Sioa od Se fRicccis- das ade bos oe eek - 18) Gils Bess oalback tens ae
Double salt (2NH, NOs. (NH4)2SO4).........-..--- 22-225 eee ee eee S255 |ELELCLE OAL ES
aston salceronm: rN Os and) KOOL) 2 o. foe oe se. Fick occ c cee seduces HG ie eke rs Se 30.2
Mixed salt (from 2NH, NOz and Kz S04)...............------22--2---2--- 1. A 1 25.0
ree enema, SISTING MOEN AE eo oo one as eg sarees ches aval lideeeeey P2100 Aap eet sep
epee entre female NOS 2.222 ~ ke Si ne cee dec wteces|oncdaeeene cad Rade ee epee
aie Siseeeers fees ite. ure 2 covey ee tye. cbt. seal) SL. Rie 196200 14-54 CREE
Se aga eas Be ee ne ese, ne = ee See Ee 1620) |25 ee tee
eemennemmemnrt ces. Oui) th S327 2 sae. A AVR BT ee 50.0

1 Solubility in 2 per cent citric acid instead of standard ammonium citrate solution.
2 Total Pe O; 8.1 per cent. 8 Total P2 O; 31.0 per cent. 4 Total Ps O; 28.7 per cent.

Cyanamid is a very important form of fixed nitrogen and is man-
ufactured in large quantities, the estimated capacity of the Muscle
Shoals plant, for example, being 245,000 tons per annum. Since it is
the direct product of the cyanamid process of nitrogen fixation, it
represents a cheaper form of nitrogen than any of its transformation
products, such as ammonium salts, and hence it is important to de-
termine its fertilizing value. Owing to its chemical nature it can not
safely be used in large quantities in mixed fertilizers containing acid
phosphate, and therefore some of the experiments were made usin
mixtures of it with calcined phosphate and basic slag as well as wit
acid phosphate. Since cyanamid nitrifies rather slowly, tests were
also made in which readily available nitrogen in the form of calcium
nitrate was used with it.

Ammonium nitrate is one of the most important synthetic-nitrogen
compounds. It can be produced by a number of methods, and
although a somewhat more expensive form of nitrogen than cyanamid
its manufacture was so highly developed during the war that it is now
available in large quantities at a price only slightly above that of
ammonium sulphate on the basis of contained nitrogen. It has the
advantage over many fertilizer materials in that it contains both
ammonia and nitrate nitrogen and does not leave a residue in the

4. BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE-

soil. It has the disadvantage, however, that it tends to become
moist under ordinary conditions of storage and handling to a some-
what greater extent than sodium nitrate. This difficulty has been
partially overcome by forming the ammonium nitrate into small
grains and coating them with an oil to lessen the absorption of mois-
ture. This treatment is comparatively inexpensive.

Among other methods which have been attempted to overcome
this handicap of moisture absorption are the production of double
and mixed salts which are less hygroscopic than ammonium nitrate
alone, and in the present experiments tests were made with such
salts as well as with ammonium nitrate. These materials include a
double salt consisting of ammonium nitrate and ammonium sulphate
and two mixed salts made by the double decomposition of ammonium
nitrate with potassium ohlorid or with potassium sulphate. The
products obtained from potassium chlorid and ammonium nitrate
are ammonium chlorid and potassium nitrate, while with potassium
sulphate they are ammonium sulphate and potassium nitrate. The
processes of manufacture of these double and mixed salts are com-
ee y simple and inexpensive. However, the necessity of using

igher grade potash salts than are normally available (particularly
the chlorid) in order to obtain sufficiently nonhygroscopic mixed
salts may constitute a rather serious obstacle to their economical pro-
duction. They have been prepared only on an experimental scale in
this country.

Ammonium phosphate will in all probability become an important
fertilizer salt within the next decade. It is especially desirable
because of its excellent physical properties and high concentration of
ee food, containing as it does both nitrogen and phosphorus. It

as been manufactured in this country to a limited extent as a ferti-
lizer material, but its commercially successful production is largely
dependent on the development of a process for cheaply producing
phosphoric acid. Important advances are now being made in this
country in the production of phosphoric acid directly from phosphate
rock by thermal or electrothermal processes.

Ammoniated superphosphate is obtained by absorbing ammonia
in acid phosphate, thus providing a carrier for ammonia without the
use of additional acid. The product is of excellent physical quality
but has the disadvantage that a part of the phosphate is reverted to
the citrate insoluble form. It has been produced only on an experi-
mental scale in the United States.

Ammonium chlorid has not heretofore been regarded as a fertilizer.
There is a possibility, however, that it may soon become available
for such purpose as a product of the ammonia-soda process combined
with the direct synthetic-ammonia process of nitrogen fixation, and
hence the value of this material as a fertilizer is of considerable
interest.

Urea possesses unusually desirable properties as a fertilizer. It is
a highly concentrated nitrogen compound, readily available, pos-
sesses good physical qualities, and when used by the plant leaves no
undesirable acidic or basic residue in the soil. While at present the
cost of manufacture for fertilizer use is prohibitive it seems probable
that this obstacle may soon be overcome.

Urephos is the product obtained by treating cyanamid with an
excess of sulphuric acid and neutralizing the latter with ground phos-

ATMOSPHERIC-NITROGEN FERTILIZERS. 5

phate rock for the purpose of rendering cyanamid more generally
suitable for use in mixed fertilizers. The material, which has been
made only on an experimental scale, contains about 5.8 per cent
nitrogen, approximately 65 per cent of which is present as urea and
ammonium sulphate, 30 per cent as guanylurea sulphate, and 5 per
cent in undetermined forms. Nearly one-half of the phosphorus is
insoluble in standard ammonium-citrate solution.

Calcined phosphate is the product obtained by heating a mixture
of phosphate rock, carbonaceous material, and an alkali salt, such as
salt cake or niter cake, in a rotary kiln. A high percentage of the
phosphorus can be obtained in ammonium-citrate soluble form in
this manner. Unlike acid phosphate, this material can be mixed
with cyanamid in any proportion without producing deleterious
changes. The new material has not as yet come on the market.

SOILS AND CROPS.

In choosing the areas to be used for experimental purposes the
necessity of limiting selections to the two Government reservations
at Muscle Shoals, Ala., comprising about 1,000 acres, proved a
handicap. This soil is for the most part poor and is rather hilly and
irregular. The most suitable areas from the standpoint of topog-
raphy and also uniformity were naturally the most fertile and less
adapted to fertilizer experiments. This irregularity naturally
minimized the value of the results to a certain extent, but nevertheless
the responses to fertilizer applications were usually sufficiently
striking to leave. no doubt as to their value. In this connection it is
important to emphasize the value of the observations made during
growth. The effects of a given treatment on germination and early
and late growth were nearly always quite striking regardless of
natural fertility and gave a better picture in many instances of the
real merits of the material than did the yields.

The total area used for experimental purposes was approximately
10 acres the first year and 20 acres the following two years. All the
work was done on areas of about 5 acres each. Three soil types,
namely, Clarksville, Colbert, and Decatur loams, were represented.
These were not widely different either in chemical or physical nature,
all being poor in nitrogen and phosphorus except in the lower areas,
which had benefited by leachings from higher levels. |

The lay-out of the plats on the various experimental fields is shown
in the diagrams (see figs. 1 to 4). The size of the plats varied from
one-fortieth to one-twentieth of an acre.

A variety of crops was grown the first year, primarily to determine
the responses from treatments of cyanamid and ammonium nitrate.
These included several vegetables, tobacco, grasses, small grains,
forage crops, cotton, and corn. The experiments of the last two
seasons were confined to cotton and corn, the crops which, together
with tobacco, receive the bulk of the fertilizer used in the South.

METHODS USED IN EXPERIMENTS.

The fertilizer mixtures used were of such a variable nature that
reference must be made to the tables given later to determine the
particular combinations tested. In these tables the term fertilizer
ratio refers to pounds of N, P,O,, and K,O in the 1919 results and to

6 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

pounds of NH,, P,O;, and K,O for the results of 1920 and 1921.
All mixtures were prepared the first year at the plats and used within
10 days, but the following two years the preliminary work was done
at the Washington laboratory and the mixture shipped to Muscle
Shoals. In the latter case from three to eight weeks elapsed from
the time of mixing until the time of application.

The methods used in preparing the soil, application of fertilizers,
seeding, and cultivation were essentially the same as those followed
by the farmers of the community. With the exception of one ex-
periment, where side applications were made, the fertilizers for
cotton and corn were applied in the row just prior to seeding. The
materials were in close proximity to the seed but never in direct
contact. Both corn and cotton were planted in rows 4 feet apart
with three rows per plat. The corn was thinned to 30 to 36 inches
in the row and the cotton to 15 to 24 inches. Harvesting was done
in the usual manner, the cotton being weighed when picked, while
the corn was allowed to dry in the shock for four to eight weeks
before husking and weighing.

The methods of fertilizing, seeding, and harvesting the winter
grains are considered in connection with the discussion of those
experiments.

OBSERVATIONS DURING GROWTH.

The effects of the different fertilizer mixtures on plant growth
under the various conditions were intimately related to the weather
conditions prevailing, particularly the rainfall. A severe drought
subsequent to planting sometimes resulted in marked injuries due to
the high concentration of soluble salts. A drought at the time of
maturity often decreased the grain yields, resulting in a yield of
stalks considerably out of proportion to the grain production. The
rainfall records of the United States Weather Bureau at Florence,
Ala., located at a distance of 3 to 6 miles from the experimental
fields, are shown in Table 2.

TABLE 2.— Rainfall at Florence, Ala., during the 8-year period from 1914 to 1921, inclusive.

Rainfall records (inches).

Month. Average,
1914 to 1919 1920 1921
1918.

JanUAry1O Ailes see ce soos ol: os oes = oP eee eae 17.37 23.70 30. 41 20. 73
IMS eee ee ney eee cet 2 5S ee See eer 3. 56 6. 96 5.70 1.14
JUNO eee ee eee ee hh 2 gee, OEM eee pe ae SS 3. 60 2.72 6.10
July eee es Pees seta ceecerts betes Pewee od epee tence bed 5. 90 1.54 3.32 6.74
PATIOS betes tee me eee ae ented un 2 ae cee sumerrntaak, Seer claw sty t 2 3. 87 5. 24 9.93 |, 3.78
September toi/Mecembers$-28 22 25s. . 2S Ik: eS 14. 67 22. 08 12. 93 14. 42

Motale® Phe BU. SPA AS Oo. AEs wn eee 48. 97 62. 24 68. 39 51.07

It will be noted from these figures that the total rainfall for the
three experimental years, 1919 to 1921, was higher in every case
than the average for the five preceding years. The total of 68.39
inches for 1920 was higher than for several years previous. How-
ever, these total figures are of much less significance than the rain-
fall of the growing season. The year 1919 was quite wet during
the early spring and dry during the growing period, with adequate

ATMOSPHERIC-NITROGEN FERTILIZERS. 7

rainfall during the period of approaching maturity. The following
year was exceedingly wet during the spring and also during August,
but a drought during July was very detrimental to the early corn.
The 1921 season was exceedingly dry the first half of the growing
period, beginning at the time of planting, but moisture conditions
were good later. The records scarcely give a true picture of the ex-
tremely dry conditions during May and June, since several local
showers which fell at Florence did not touch the experimental

fields.

CYANAMID.

The germination of cotton and corn was not appreciably affected
under any conditions by applications of cyanamid at not to exceed
the equivalent of 40 pounds of ammonia per acre. With double
this quantity there was a distinct retarding, and in instances where
the moisture was deficient the germination was slightly below nor-
mal and many of the plants died soon after appearing above the
surface. Under similar conditions ammonium sulphate and sodium
nitrate also produced bad effects, but to a lesser extent.

The early growth with cyanamid was decidedly different from that
with any of the other materials used. For about one or two weeks
in the case of corn and three to five weeks with cotton the plants
were retarded and usually made no better growth than on the check
plats receiving no nitrogen. The larger the application the greater
the amount of retardation. With both crops, especially cotton, the
plants became an unusually dark green, the color persisting until
maturity. During the first and third years, when moisture was
deficient, cyanamid at the larger rates of application produced a
marked burning of the leaves. Where side applications were made,
a similar burning was observed after these late applications but dis-
appeared shortly after rain fell.

The later growth of corn showed a rapid recovery from any initial
injuries, and usually there was no appreciable difference between the
cyanamid, ammonium-sulphate, and sodium-nitrate plats. With
cotton the results were frequently very strikingly different. For
instance, during the season of 1919 on cyanamid was used in
mixture with acid phosphate, approximately two months were re-

quired for any increase in growth even with the smallest application.

The characteristic dark-green color was early in evidence. The first
plants to show increased growth were those receiving the smallest
applications of nitrogen. This peculiar behavior was undoubtedly
due to the high content of dicyanodiamid which formed from the
cyanamid in the presence of acid phosphate. During the season of
1920 and 1921 where the cyanamid was either mixed with basic
phosphates or applied separately with acid phosphate the observa-
tions were quite different, as shown by Plate I, Figures 1 and 2.
There was always a retarding period of two to four weeks, which was
nearly always overcome. However, the material was not as satis-
factory a nitrogen carrier for cotton as either sodium nitrate or
ammonium sulphate.

The time of maturity of corn was not appreciably affected by the
various cyanamid treatments. With cotton, however, the early
retarding effects were never entirely overcome, and as a result the
plants usually did net grow quite as large or the bolls mature as

8 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE,

quickly as with sodium nitrate. The difference usually amounted to
two or three weeks and played an exceedingly important part in the
final yields for two main reasons: (1) The damage by boll weevils,
which are always present in the largest numbers fists in the season,
was greatly increased; (2) cotton requires warm weather and a long
erowing season, and the delay in the growth in many instances
resulted in the plants being killed by frosts before the growth was
completed. This was especially important in these experimental
results, due to the fact that Muscle Shoals is located within about 75
miles of the northern limit of the Cotton Belt.

The effect of cyanamid on the growth of wheat, rye, oats, and
erass was not appreciably different from the responses with sodium
nitrate and ammonium sulphate. Where all of the cyanamid was
applied in the fall, there was sufficient time for the nitrogen to become
available before being used by the plants the following spring. Con-
sequently the resulting growth was good. Where a portion of the
cyanamid was applied in the spring to wheat and rye, a retardation
resulted, and these plants were slow to recover. On the whole
cyanamid was a much more satisfactory fertilizer for the winter crops
than for cotton.

The use of calcium nitrate with cyanamid was tried out on a small
scale in an effort to stimulate the early growth. The results were
not entirely satisfactory, due perhaps to the fact that the mixture
used was somewhat incompatible. The combination included cyana-
mid, calcium nitrate, and basic slag. The nitrate absorbed sufficient.
moisture from the air to result in the formation of unusually hard
cakes. Probably at the same time some of the cyanamid was con-
verted into dicyanodiamid, a poison for many plants. Under such
conditions the cyanamid—calcium-nitrate mixture was no better
than cyanamid alone, but it is felt that these unsatisfactory tests are
no indication that the use of nitrate nitrogen with cyanamid will not
prove profitable provided the materials are applied separately or in a
compatible mixture.

AMMONIUM NITRATE, DOUBLE SALT, AND MIXED SALTS.

The effects on growth produced by ammonium nitrate and the
combinations which may be made from it for the purpose of over-
coming part of its objectionable hygroscopic properties were exactly
alike so far as the eye could detect. The observations are therefore
discussed under the same heading.

The germination and early Bei of cotton and corn in the presence
of these materials corresponded in every respect with that noted
with sodium nitrate. Where moisture was deficient there was a
delay of two or three days in germination with the two larger rates
of application, and sometimes a slight burning effect, especially in
the case of corn. These slight temporary injuries occurred. only
under extreme conditions and were no greater than with sodium
nitrate. Ammonium ‘nitrate and its combinations all gave quick
responses and behaved in identically the same manner as sodium
nitrate. The growth with cotton and corn is shown by Plate I,
Figures 1 and 2.

Late growth and maturity also corresponded to that on the plats
receiving equivalent amounts of nitrogen in the forms of sodium
nitrate and ammonium sulphate. The smaller applications hastened

ee ee ee eee

Bul. 1180, U. S. Dept. of Agriculture. PLATE I.

teal

« et
¥

a°

FiG. |.—FIELD OF COTTON SHOWING INJURY CAUSED BY A HEAVY APPLI-
CATION OF CYANAMID USED IN MIXTURE WITH ACID PHOSPHATE. FIELD
1, SEASON OF IQIQ.

At left, cyanamid, 1,00) pounds 8-8-0 fertilizer per acre; yield 548 pounds of seed cotton. At
right, no nitrogen, 1,000 pounds 0-8-0 fertilizer per acre; yield 980 pounds of seed cotton.

nn

FIG. 2.—COTTON GROWN THE FOLLOWING YEAR ON THE SAME AREA
SHOWN ABOVE, USING CYANAMID WITH ACID PHOSPHATE APPLIED SEPA-
RATELY. FIELD |, SEASON OF 1920.

At left, cyanamid, 1,000 pounds 8-8-4 fertilizer per acre; yield 1,908 pounds of seed cotton. At
right, no nitrogen, 1,000 pounds 0-8-4 fertilizer per acre; yield 1,204 pounds of seed cotton, }

Bul. 1180, U. S. Dept. of Agriculture. PLATE II.

FiG. |.—GROWTH OF COTTON WITH AMMONIUM NITRATE. FIELD I, SEASON
OF 1920.
At left, no nitrogen, 1,000 pounds 0-8-4 fertilizer per acre; yield 952 pounds of seed cotton. At

right, ammonium nitrate, 1,09) pounds 8-8-4 fertilizer per acre; yield 2,040 pounds of seed
cotton

FIG. 2.—GROWTH OF CORN WITH AMMONIUM NITRATE. FIELD |, SEASON
OF 1921.

At left, ammonium nitrate, 1,000 pounds 4-4-2 fertilizer per acre; yield 25.7 bushels. At right,
no nitrogen, 1,000 pounds 0-4-2 fertilizer per acre; yield 7.4 bushels.

ATMOSPHERIC-NITROGEN FERTILIZERS. 9

maturity slightly while the largest amounts produced a slight re-
tardation, as is usually the case with other readily available sources
of nitrogen.

Ammonium nitrate where used on winter crops gave exactly the
same effects as sodium nitrate, and it was impossible to detect any
difference between the two treatments at any time during the grow-
ing season.

AMMONIUM PHOSPHATE AND AMMONIATED SUPERPHOSPHATE.

The early-growth effects in the experiments with ammonium phos-
phate and ammoniated superphosphate were excellent, both the
cotton and corn usually being as large as or larger than any in the
field during the first six weeks of growth. The materials were as
available as ammonium sulphate and showed no bad effects except
in cases of extreme drought, where large applications of all soluble
salts injured the plants. The materials were unquestionably good
nitrogen carriers. aatee:-

The growth during the latter half of the season was likewise good,
but owing to the abnormally large quantities of phosphorus supplied
the increases over the check plats tended to become less and less pro-
nounced as the season advanced. Even though the primary purpose
of these experiments was to determine the availability of the nitrogen
it was impossible at the same time to avoid adding an abnormally
large quantity of available phosphorus. The soils on the experimen-
tal areas were rather deficient in this element, and hence its stimu-
lating effect largely obliterated the responses produced by the
nitrogen. ;

AMMONIUM CHLORID.

Germination was slightly injured by the largest rates of application
in a few instances, the effects being a little more pronounced than
with equivalent applications of sodium nitrate or ammonium sulphate
used under similar conditions. During the two weeks subsequent to
germination there occurred a distinct pune in some instances,
Selene ed with corn receiving 40 pounds of ammonia per acre.

uring the season of 1920 this injury was sufficient to kill about 10
per cent of the corn plants.

The later growth corresponded to that on near-by ammonium
sulphate plats except where the most severe burning took place. In
these cases the plants never seemed to overcome entirely the early
retardation. ith the smaller applications, where no burning oc-
curred, the corn and cotton seemed to make even better growth than
with ammonium sulphate. These facts suggested a possible injury
in the presence of a iis concentration of the chlorid ion and a stim-
ulation with smaller quantities. Any bad effects noted were much
more pronounced in 1920 than in 1921, even though used on the
same soil both years. The latter year ammonium chlorid produced
effects more nearly corresponding to those noted with ammonium
sulphate.

UREA.

The observations during growth showed no difference at any time
between the urea plats and those receiving either of the two standard
materials. Urea produced no germination injuries, was immediately

10 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

available for the young corn and cotton plants, and continued to
produce good effects until maturity. The material gave every evi-
dence of being a satisfactory nitrogen carrier from all standpoints.

UREPHOS.

The effect of Urephos on wheat and rye, the only crops which re-
ceived this material, was not markedly different from that with the
standard materials. In the case of wheat the growth with Urephos
was very good, while the growth of rye was somewhat poorer. This
was undoubtedly due to the marked soil variations. No toxic or
retarding effects were observed at any time.

EXPERIMENTAL RESULTS.

The experimental work of the first year was of a rather miscella-
neous nature and in general differed considerably from the later work.
It will therefore be discussed separately.

EXPERIMENTS OF 1919.

Two series of fertilizer tests were started in 1919, one with summer
crops and the other with winter crops. The former included experi-
ments with cyanamid and ammonium nitrate on corn, cotton, and
miscellaneous crops on field No. 1. The latter experiments were
with the same fertilizers on wheat, rye, oats, and grass. A new ferti-
lizer known as Urephos was also used to a limited extent on wheat
and rye. These winter crops were grown on field No. 2.

Fietp No. 1.

Three sets of experiments were carried out on this area during the
first season, using cyanamid and ammonium nitrate in comparison
with sodium nitrate. They were as follows: (1) Availability experi-
ments with cotton and corn, (2) time-of-application studies with
cotton and corn, and (3) availability tests on various types of crops.
The work was started late in the season and was delayed by wet
weather. The yields were accordingly diminished, and furthermore
in some cases frosts came before maturity was reached.

AMMONIUM NITRATE, SODIUM NITRATE, AND CYANAMID ON COTTON AND CORN.—SEC-
TION I.

This experiment was planned to determine the relative values of
ammonium nitrate and cyanamid at different rates of application as
compared with sodium nitrate, using the materials in the row at the
time of seeding, asis commonly done. The yields are given in Table 3.

It will be observed that ammonium nitrate gave as large increases
of cotton and corn as did sodium nitrate, any differences being within
the range of possible experimental error. Thus, the yields agreed
with the observations previously mentioned.

The results with cyanamid were poorer than with either of the other
two fertilizers. This was due almost entirely to the fact that the
cyanamid was mixed with acid phosphate and allowed to stand for a
few days before use. Laboratory studies later showed that under
such conditions a considerable portion of the cyanamid may be

|

|
|
|

|

ATMOSPHERIC-NITROGEN FERTILIZERS. EI

changed to dicyanodiamid. The latter material is not only unavail-

able as a fertilizer but is toxic for some crops and delays the nitrifica-
tion of the soil organic matter or of any nitrogen added as a fertilizer.
Furthermore, in mixtures of cyanamid and acid phosphate, such as
were used in these experiments, there occurs a reversion of the ‘phos-
phorus to a less available form.

TABLE 3.— Yields per acre of cotton and corn from Section I of field No. 1.

Yields of seed cotton Yields of corn.

(pounds).
Fertilizer ratio.1 | Plat. Plat. Grain (bushels).
Increase Stalks
Actual. ea A (pounds). Trerouke
oe Actual. | Average.| over
| check.
Series A.—Ammo-
nium nitrate:
oC Oe ee Pee oy ESE ae oe te ee 20 0 g50-|,2AEU A>
ee 1 713 y 9 ; ;
0-8-0. wee ee eee I 5 765 739. 0 w~eeeeunesce 13 v US ies ¢ 19. 6 ereeesr eres
lf 21. 1,273 10 21.
os eae ee | Vos7 |p 1180.0] 44.0 44 2, 500 an 28.6 9.0
3| 1/250 : ul ’ 34.9
4-8-0, -9...!.. \ i 17330 |f 4240-0) 50.0 15] 2600] sz4|p 362 16.6
4| 1,362 : 12|} 2560 33.4
bs aa fe: 4 g| 1353 |p 4357-5] 61851) 16] 5°88 a \ 36.3 16.7
nes D.— um
nitrate:
OOD scot. Bee: 293 | 293 en eee enna] eeagelenee siay fo cacakcciee poe
ij 1 : 9 “48 31.4
0-8-0: 22.1.2. 5 905 ro) se eae ee 13 2, 260 30.3 | 30:9: |_4-5-82 4-6
2| 1,110 10| 3,200 39. 4
2-8-0. -_—eeeereeee 6 it, 280 Ls 195. 0 333. 5 14 2 920 33. 7 36. 6 5 vA
3] 1.353 11 040 44.6 if
£6 t?. any ri 1,379.0] 517.5) 35] 3°44 ree } 45.8 14.9
2h 12} 3,600 54.3
ce eae 1 8] 17380 |f 1405-0] 543.5 |1 38]. 9800 yr } 49. 5 18.6
Sate C.—Cyana- |
. mia:
OOO iL EN aoe ATL ni, Secaeenel ICC Bereeeraren (UC Sateen CPOE Al ONS
1| 1.195 fs 9| 2,400 26.9
O84 Sus et. : pe W087. 5, [6 2 25) 15 1 Bs ee } ped eee
2| 1,208 : 10 ” 680 24.9
S895 $5 - 4h 6 | 17205 |f 1208-5] 158.0 8 3g] Fg00 ae 21.2 Baie
3| 1113 11| 27360 32.0
a? eee apie G7 ine lt 1, 124-0 86.511 35] 5° 360 pa 29.6 7.3
4 548 -|f 12] 27120 30.6
$-8-06 oi Jf: ; 339 |} 690-0| —357.5 11 18! {’d00 ue 29.6 13

1 The term ‘‘fertilizer ratio”’ used in Tables 3 to 7, inclusive, refers to the percentages of N, P2O;, and
K;0 per acre, in the order named. The applications were made at the rate of 1,000 pounds per acre.

It is quite evident, therefore, that no particular weight should
be attached to these yields with cyanamid, used under conditions
that are known to be unsatisfactory. They are, nevertheless, valu-
able in demonstrating that cyanamid should not be used in large
proportions in fertilizer mixtures containing acid phosphate.

TIME-OF-APPLICATION STUDIES WITH AMMONIUM NITRATE, SODIUM NITRATE, AND
CYANAMID ON COTTON AND CORN.—SECTION II.

In order to determine the best time to apply the nitrogenous
fertilizers, a series of plats was planted to cotton and corn, some
plats receiving the nitrogen in the row at the time of seeding, others
one month later, and a third group receiving half of the Pictibaee

12 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

when seeded and the remainder one month later. Where the ferti-
lizer was applied after planting, the material was distributed by hand
in the furrows left by the cultivator used for the second cultivation.
The distance varied from 6 to 12 inches from the row. The fertilizer
was then mixed with the soil by means of a spring-tooth cultivator.
Table 4 gives the yields from the various plats.

TABLE 4.— Yvelds per acre of cotton and corn from Section II of field No. 1.

Application Yields of seed cotton F
of nitrogen. (pounds). Yields of corn.
Fertilizer ratio. Plat. : Plat. Grain (bushels).
- One a
With Aver- | crease Stalks
seed. month Actual. age. over (Ibs). Increase
later. check. Actual. Aver- over
age. | check
Series A.—Am-
monium nitrate:
Sy a Fe { Sey. BOA A beat |2oc Cagle. cast \cdubebee te it a
1] 840 9| 2,380| 31.1
ee or ee re { 5) | 990 ein the See { 13] 1760] 3219 |} 27-0 |.-....-.
5 10] 3,220] 40.0
Bact ot he ati. eT al co ta t He \ 1,370 4551 i4| 9’s00| 35:7 |t 379) 10.9
0 11] 27960] 46.6
4-8-0. 2222... Half..| Half.. 1] x 405 \ i318} 403 15] 2700 | a6 \ 42.6] 15.6
ml 27340] 44.9
4-8-0. .-...2--)2--22-- All { 8| 13310 \ 1,175 260) 46 27260 | 34.3 \ 39.6 12.6
Th, Seas WD lt ae 1 1 fs boat De 1,300] . 15.2 oasa-d! gate
Series B.—Sodi-
um nitrate:
COTE De Sie ey ere a Pea { go «20 fe SRM Ah oe 1,590: 744 -:-9,40ed
1 653 9| 2,120] 22.0
Ca eo Se i eae 5| | 608 iesied aia { 13 2,320 96.0 |} 240 )--------
8 340| 46.6
4-8-0. 2.22222. 7S 6| ro |p Ltt} 513 ta] 3580] azia |} 47-0] 23-0
48-0 Halt... ae >| yao |} 1173) 42 a5] Seen | aaa |} 48-0] 220
; ]
4 12] 23930] 43.1
4-8-0... 22-02.) ---- 2+ All...) | a070 |} %7} 3361) 161 2500| 383 \ 40.7 | 16.7
eS SEI ee ep Se AND 7 ok ae GO tee endl pee pes 1,520). 4d og, dels
Series C.—Cyana-
mid:
(em ah Ne ES Pe ea s-] 1 283) 283 feveeefeeee g| 29] 83] 63 |-------
3 .
Bae eae be ot ee { 5 1,163 } 1 232 J... { 13 2; 780 33.4 aii
8 10| 3,540 pe
428)! 2 ee AT oe { ; 1385 1,107] —125 1 34] 3360 10-0 41, 25A-C11.6
3 | 1,300 11] 3,400] 42.
eg Half..| Half 3) vito 25] = 27 as): 8000) acd \ 42.2} 12.6
4| 1,118 12| 3,320] 43.4
4-8-0 ween eeweee| ee eees tN Pere 8 988 \ 1,053 —179 { 16 2; 820 40.0 \ 41.7 12 1
AEN EAT calle! oa: yO pile 106 [ts epi ME) ae 780'| ves doll eargrl eee

In considering the results it is necessary to emphasize the wide
variations in the natural fertility of the soil on different portions of
the field. This accounts for most of the irregularities shown by the
figures in Table 3. Ammonium nitrate again gave responses similar
to sodium nitrate, although the increases in yields were not quite as
large. Cyanamid was a very unsatisfactory fertilizer, for the reasons
already given. From the standpoint of time of application there was
no great difference in the yields whether all or only half of the fer-
tilizer was applied with the seed. Where no fertilizer was applied
with the seed the yields were nearly always lower. This emphasizes
the necessity of having sufficient nitrogen available for seedlings to
give them a rapid start.

ATMOSPHERIC-NITROGEN FERTILIZERS. 13

The deficiency of phosphorus in the soil is shown in Table 4. The
yields of both cotton and corn were usually larger on the untreated
plats than where nitrogen alone was used. With both nitrogen and
phosphorus there was a very large increase in yields.

AMMONIUM NITRATE, SODIUM NITRATE, AND CYANAMID ON MISCELLANEOUS CROPS.

Experiments with the three fertilizers mentioned were made on a
wide variety of crops, including cowpeas, soy beans, string beans,
sweet potatoes, tomatoes, potatoes, tobacco, okra, Lima beans,
sorghum, millet, turnips, and Sudan grass. The results were of a
qualitative nature and hence are not here reported in detail. A few
of the more significant effects of the fertilizer treatments are, however,
included.

Ammonium nitrate gave results comparable with sodium nitrate.
The material was readily available and suitable for forcing vegetables.
Cyanamid was much slower acting and gave lower yields because of
its dicyanodiamid content. But even where used according to best
—_ cyanamid as the only source of nitrogen will not be a suitable
ertilizer for quick-growing crops.

FIELD No. 2.

Three sets of experiments were conducted in 1919 on field No. 2,
as follows: (1) Availability studies with ammonium nitrate and
cyanamid at different rates of application, using sodium nitrate and
ammonium sulphate as standards; (2) studies of the effect of lime on
availability, usmg the same materials; and (3) tests of the fertilizing
value of cyanamid and Urephos in comparison with the two standards.

e crops grown included rye, wheat, oats, and a mixture of redtop
and orchard grass. Planting was done December 10, 1919, just
subsequent to broadcasting the fertilizers. A wheat drill was used
for genkey the grains, while the grass seed was distributed by hand.
The rye plats were harvested on June 8 and the other crops on June
21." The crops were allowed to remain on the ground until thoroughly
dry, and then the total weights were SBincwesl Unfortunately there
was no equipment available for threshing and hence the grain yields
were not determined.

The fertilizer application included nitrogen in the different forms
at varying rates up to 80 pounds per acre, together with phosphorus
and potassium. ‘The latter two elements were applied at the rate of
80 pounds of P,O, and 40 pounds of K,O to all plats of Sections I and
II except those designated as ‘“‘no fertilizer.” On Section III 65
pounds of P,O; was used on all plats except those receiving Urephos,
where the application was 90 pounds of P,O,. The sources of phos-
phorus are shown laterin Table 7. The fertilizers were mixed about
one week before applyimg them except where cyanamid was used, it
being applied separately. The method of making fall applications
was to broadcast the mixtures by hand, followed by a thorough
harrowing before seeding. The spring applications of nitrogen
where given were broadcasted on the various plats about April 15.

In considering the experimental results reported below it will be
observed that in many instances the variations in yields between

14 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

duplicates are quite large. This is due to the fact that in nearly all
instances duplicate plats were located at a considerable distance from
each other and the soil variations were sufficient to account for the
discrepancies. While these variations were large, nevertheless there
was usually a gradual change in productivity from one portion of
the field to another.

AVAILABILITY STUDIES WITH RYE AND WHEAT.—SECTION I.

This experiment was planned to give comparisons in yield between
ammonium nitrate, sodium nitrate, ammonium sulphate, and cyan-
amid at the rates of 10, 20, 40, and 80 pounds of nitrogen per acre.
Half of the nitrogen was applied in the fall and the remainder as a
spring top-dressing except in one series, where all the cyanamid was
applied in the fall for the purpose of comparison with the other
method of use.

The differences in growth on the various plats were quite marked
and also fairly uniform for the different sources of nitrogen at any
given rate of application. Very early in April the growth on all plats
was quite poor because of the late planting and very heavy rainfall
both in the fall and spring. The soil on the entire area, and especially
the ammonium-nitrate series, was not quite as well drained as is
desirable. Soon after making the spring applications of nitrogen
there was a very rapid growth which corresponded approximately to
the total nitrogen supplied. The rye and wheat which received no
nitrogen were the smallest and lightest in color, while that receiving
the largest amount of nitrogen grew very rapidly and had a very
dark green color. There was no appreciable difference between the
different series of plats, except that where the spring application of
cyanamid was made there was a slight retarding effect as compared
with the other cyanamid series.

The yields of grain and straw from the plats receiving the four
different sources of nitrogen are given in Table 5. In considering the
results for rye it will be noticed that usually the larger the amount
applied up to the maximum application of 80 pounds of nitrogen per
acre, the fafoer was the yield. With regard to the merits of the four
sources of nitrogen, making allowance for soil variations, neither the
growth nor yields indicated any marked differences. Ammonium
nitrate produced larger yields than did the adjoining sodium-nitrate
series, but the check plats were also better. The yields from the
plats where all of the cyanamid was applied in the fall were the
largest of any of the series and likewise showed the largest increases
over the checks. The soil variations are too great to justify making
sharp distinctions, but there is not the least doubt that cyanamid,
when applied in the fall, produced results equally as good as any
other fertilizer used.

The wheat yields agreed very closely with those for rye and showed
that under the conditions ammonium nitrate and cyanamid were as
satisfactory sources of nitrogen as sodium nitrate and ammonium
sulphate. The application of all of the cyanamid in the fall again
gave slightly better results than the use of half in the fall and the
remainder in the spring.

ie

ATMOSPHERIC-NITROGEN FERTILIZERS. 1S

TABLE 5.— Yields per acre of rye and wheat from Section I of field No. 2.

Yields of rye (pounds.)| Yields of wheat (pounds).

Fertilizer ratio. Grain Increase | Grain Increase
and Average.| Over and Average.| Over
straw. check. straw. check.
Series A.—Ammonium nitrate: ea an
Beto Oi ei Bola {) 940 |} 1,440 Jase eee {1 6a0 [ff 15160 [dss eee
Spe) 9G Ty OF) 20.8: { 360 |} 2,000 560 { 7’ 4ao |} 1,420 260
J 5]
4. Se { ae \ 1, 860 420 { ee \ 1,720 560
, 2
a he Le Ca 1. PBa0|t 1,980 520 390 |} 2440] 1,280
3 >
a { $380 \ 2,840) 1,400 { 3o10 ft 2540 1, 380
2’ 280 2; 560 .
a 2 Ee ee ee See ae { 5990 |f 2600, 1,160|{ S259 )} 2,540] 1,380
Series B.—Sodium nitrate: rs
3 py eae ieee { ae \ TMM pose { 360 1100 bins aed
ares 2 OUUE a resting. 5-20 { mre ri {ig 1600). gf is { 2 480 7 ene wee,
Oo a, We ol oe CE Mie { 3360 |t 1,380 2201 460 [+ 2,040 —40
, ,
poe Fer ON bo! { it \ 1, 700 540 { nee \ 2, 360 280
I >]
ot ek ae eee { 2°ou0 |} 1,960 800 {57509 |t 2,500 420
2 ,
1, 840 3’ 360
Bee ee 2 OHS.) OR. { 27590 |f 380} 1,220} 57359 | 2,840 760
Series C—Ammonium sulphate: Lexy Sag
3; a3 ager era Cae aa Pte ts bt40,|-.----0-- Ne drone (t 1s 840 eee
(SS S nee { Ne ea \ 1 360.|...... Peart { ee \ 1, 740° |. Bee aoe
ne ,
Seo ES Sree eee one \ 1, 420 160 i vee \ 1, 500 —240
’ ,
Pee het. eee 1 Se ayes \ 1, 980 720 { an \ 2, 260 520
, ,
2) Ss SS eee rae nba \ 2,320| 1,060 { ae \ 2,520 730
) ,
f 3,200 2’ 720 \
eee eee Oe A en aa \ 2,860} 1,600 { 7430 |¢ 29720 980
Series D.—Cyanamid: ae +666
Oe ee 1,280 \ GH) |. eee. { De \ oi a a
Us ea ees gti \ 1,000.|... ocait { 1780 [} 1,000 |-2-22----
SESS hess eae { ge \ 1,380 380 { nee \ 1, 100 100
? ]
Ul 2 ES ae { vo \ 1,680 | 680 { ae \ 1, 220 220
? ,
oS OT eee { ae \ 2,320) 1,320 { pres \ 2,020 1, 020
a | ]
2; 320 3, 000
Ls Bypass Spee Rely nepal ad { 2 880 \ 2,600 1,600 { 2 400 \ 2,700 1,700
Series E.—Cyanamid (applied in the fall):
pie SEA TY Oe Oto Woe { es \ 920 |...-..2.-- { epstn \ 680 PLsAT
|
ge Li edges eae eal { an \ Tele ee { wes \ ioib. Pues ees
>]
er Fe chong \ 1, 840 340 { een \ 1, 280 240
d
“RS OS tee eee { webs \ 2, 220 720 { aay \ 1,680 640
I ,
ren iin (ig) fever boar { nem \ 3,020| 1,520 { meee \ 2,160 1, 120
, ,
Pps IUGR 40 { rar \ 3,460| 1,960 { eee \ 2, 900 1, 860
= 5) py

1 Half of the nitrogen was derived from ammonium nitrate and the remainder from sodium nitrate.

INFLUENCE OF LIME ON THE UTILIZATION OF NITROGEN FROM THE VARIOUS SOURCES.—
SECTION It.

_The importance of the soil reaction on the availability of ammonium
nitrate and cyanamid was determined for wheat, rye, oats, and grass.
Nitrogen was supplied at the rate of 40 pounds per acre, half at the

16 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

time of planting and the remainder as a spring top-dressing. Where |
lime was used, the rate of application was 2 tons of air-slaked material |)
per acre.

The growth on this group of plats was rather disappointing early
in the spring, owing to a poor stand and the retarding effect produced
by wet weather. However, as the season advanced very good stool-
ing took place and the poor stand was partially overcome, resulting |
in fairly uniform growth on plats similarly treated. Since the appar-
ent discrepancies in the yields shown in Table 6 may in many cases
be explained by observations during growth, the two will be discussed |
together. |

TABLE 6.— Yields per acre of wheat, oats, rye, and grass from Section IT of field No. 2. |

Yields of grain and straw (pounds).

Crop and fertilizer ratio. Limed or unlimed. Series A.—| gorias B.—| Series C.—
Ammo- Sodium. mmo- | Series D.—
nium nitrate nium Cyanamid. |
nitrate. : sulphate.
Wheat
Cs RR awe ek Se Unlimed..=. -. us Ue 160 760 app ere
ARSm a) ee ae Fee re a 3S J GOse 553-655 eee eee 1, 640 2,520 2,760 1,520
pS oe oe Pee een Limed2 0. 225 Rie ae 2, 400 2, 440 2, 320 000
Increaseidue tojlime:.|2 jh. 52 sash sete ea 760 —80 —440 480
Rye:
My tN eek ee Limed.....o2 5: pee ee 1, 640 1,760 1,400; |: .-Sodoe eee
ge ee eee EE Wnlimed) 2322 2-2 c ee 2, 440 2, 480 2, 800 2,760
0 ee Rots at San ae Lamed).... 22 ose aes 2, 960 3, 440 3, 006 , 200
Increase: due to lime: 2}. 32-205. 2.25 2S 520 960 200 —560
Oats:
oF ei ae tp eet Unlined) .2,4:82- soe ae eee 2, 3, 320 2, 200 2, 400
A484 See 8 Sh cee ce Lamed) 22525 Ae aoe fee 2, 520 1, 920 2,160 2,720
increase GueitOwime: 2)... 252-25 nbe acu epee —360 —1, 400 —40 320
Grass:
AR Ae UA se ee Uniimed’.":2 4 232s ; 2,320 1,600 1, 240
etd Se ee a oa oe ainted 2 8s sce ec see 2, 920 2,720 1, 640 1
Increase due tolime:.}: 22. 2.5. 205.24 - 42. 2 32s p 920 400 40 0

The addition of lime, judging from Table 6, produced a rather
marked increase in the growth of wheat fertilized with ammonium
nitrate and cyanamid, while slight losses were shown with sodium
nitrate and ammonium sulphate. However, the plats receiving the
latter two sources of nitrogen had a very poor stand. Had the
number of plants and the soil conditions been the same in all cases
there is little doubt, judged by the results obtained by other investi-
gators, that lime would — given increased growth with all sources
of nitrogen and particularly with ammonium sulphate, since this
material leaves an acid residue in the soil.

The yields of rye were increased by additions of lime in the case of
all of the fertilizers except cyanamid. It is barely possible that the
lime exerted a harmful effect, but more likely the soil variations
largely explain the results. The plat which yielded 2,760 pounds
appeared to the eye to be naturally more fertile than the plat which
yielded 2,200 pounds.

ATMOSPHERIC-NITROGEN FERTILIZERS. 17

The yields of oats are no doubt misleading, since cyanamid is the
only one of the fertilizers which shows an increased yield with lime,
the very reverse of what was obtained with rye. LEarly-spring obser-
vations showed that the stand was much poorer on the limed than
on the unlimed plats, thus accounting, at least partially, for the
lower yields.

The growth of redtop and orchard grass was good and the stand
quite uniform. The results are therefore more significant, lime being
without effect with cyanamid but beneficial with the other nitrogen
calriers.

CYANAMID AND UREPHOS AS FERTILIZERS WITH DIFFERENT PHOSPHATE CARRIERS.—
SECTION IIil.

This experiment was planned primarily to compare mixtures of
cyanamid and either basic slag or calcined phosphate with sodium
nitrate and ammonium sulphate as standards. In addition, a few
plats received Urephos, which contains both nitrogen and phos-
phorus. Im all cases except on the check eet nitrogen was sup-
plied at the rate of 40 pounds per acre, half in the fall and the re-
mainder in the spring. Phosphorus and potash were supplied to all
plats in the fall at the rate of 65 pounds P,O; and 40 pounds K,O. In
the case of Urephos either basic slag or acid phosphate was used to
bring the total phosphoric acid content to 65 pounds for the fall
application, but when an additional application of this material was
made in the spring the total phosphoric acid was brought up to 90
pounds per acre. The crops grown were wheat and rye.

In considering the yields shown in Table 7, it will be observed that
there are several wide variations in the yields of plats receiving the
same treatments. This is because the duplicate plats were located
at a considerable distance from each other, and the variations merely
show the natural soil irregularities, which were beyond control.

TaBLE 7.— Yields per acre of wheat and rye from Section III of field No. 2.
|

Yields of wheat (pounds). | Yields of rye (pounds).

Ferti-
Aeostnent,. jzer | Grain | Increase! Grain | Increase
; and (Average.| over and (Averagé.| over
| straw. | check. | straw. | check.
Le ral eS Pa a a ee eae
No nitrogen (basic slag)............-.-- 0-6. 5-4 { ea \ 740 |e. i 2, 040 i 1,000 |. eS
Sodium nitrate (calcined phosphate)...} 4-6. 5-4 { oe \ 1,560} 820 it } 2, 040 | 540
ey. N 2; 240 s 1,300 | :
Sodium nitrate (acid phosphate)....... 46,5-4 { 130 \ 1,300 | 1,060 i ee \ 2, 040 540
Ge ing f 21 f 22200
Sodium nitrate (basic slag).........--- 4-6. 5-4 \ 800 \ 1,980 | 1,240 { oto |} 2,300 800
Ammonium sulphate (acid phosphate).| 46.54 { ara \ 1,980} 1,240 (| a } 2, 280 730
Cynamid (calcined phosphate)......... 4-6, 5-4 { pe \ 2,000} 1,260 { vee \ 2, 240 740
5) 7
Cyanamid (basic slag)..........-...-.- 4-6.5-4 { 2 190 \ 2,100} 1,360 { i = \ 2, 220 7
Urephos (basic slag)..........-..-.---- 494 { a \ 2,400! 1,660 { — \ 1,740 240
Urephos (acid phosphate)............. 49-4 A aan \ 1,900 | le | ee Pein ieee tee
; | |

52765°—-24— Bull. 1180-2

re SS

18 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE. |
|
|

The growth and yields in the case of wheat showed no appreciable
difference between cyanamid with either of the two basic phospha tii |
and ammonium sulphate with acid phosphate. The yields of wheat | ;
with sodium nitrate used in mixture with basic slag were also on a | ,
par with the cyanamid and ammonium-sulphate results. With cal-
cined phosphate and acid phosphate sodium nitrate gave smaller | ,
increases than any of the other mixtures. No significance should | ,
be attached to this, however, since these plats were located on if
poorer soil. Urephos gave very good growth, giving the best yield | ,
with basic slag of any of the mixtures and an average yield with |
acid phosphate. The large application of phosphorus may have |
partially accounted for the good results.

The growth and yields of rye showed no appreciable difference |
between cyanamid, ammonium sulphate, and sodium nitrate with the |
different as carriers except that some of the yields with sodium
nitrate were low because of the poor soil on this portion of the field.
This is shown by the wide variations in the yields of the two check
plats. The yields of n° where fertilized with Urephos and basic

O

slag were the lowest of any of the forms of nitrogen. The soil is |
decidedly poorer on this portion of the field, and doubtless this largely
accounts for the low yields. Urephos seemed to give as good responses },
in growth as the other materials, but the fact that approximately |
30 per cent of the nitrogen is present as guanylurea sulphate leaves |
some doubt as to its value in general, since the latter compound is |
probably only very slowly available for plant use.

EXPERIMENTS OF 1920 AND 1921.

The agricultural experiments reported above were continued at
Muscle Shoals during the following two years. Modifications in
the manner of using cyanamid were made, and the scope of the work
was enlarged to include several additional nitrogen carriers.

The methods of carrying out the experiments were essentially the
same as those used previously except for variations in the fertilization.
In order to make nitrogen the limiting factor all plats except those
designated as ‘‘no fertilizer”? received potassium and phosphorus.
The rates of application used as a basis were 80 pounds of P,O; and
40 pounds of K,O for cotton and usually half these quantities for
corn, but certain modifications had to be made where the nitrogen
carriers contained either of these two elements. The sources of phos-
phorus and potassium were acid phosphate and potassium sulphate
unless otherwise noted.

The experimental area included the 10 acres used previously, the
yields from which have been given, and three additional fields of
about 5 acres each, located near by. The layout of the plats,
giving treatments for the season of 1921, are shown in the diagrams.
(Figs. 1 to 4.)

Fretp No. 1.
}
|

The experimental work of 1919 on field No. 1 was continued during
the following two years, using the same plat arrangements and so
far as possible similar treatments for the same plats. The results
are discussed under three headings corresponding to the three sec-
tions of the field. A diagram of the field, showing the plat arrange-
ments and treatments, is shown as Figure 1.

ATMOSPHERIC-NITROGEN FERTILIZERS. 19

AMMONIUM NITRATE, SODIUM NITRATE, AND CYANAMID.—SECTION I.

Results with cotton—This set of experiments was practically a
duplication of the work of 1919 except that where cyanamid and
acid phosphate were used the materials were applied separately.

The yields for the two years, given in Table 8, show a slight dif-
ference in favor of sodium nitrate over ammonium nitrate. How-
ever, it is felt that the soil variations were great enough to account
for most, if not all, of the differences. Both the sodium-nitrate and
cyanamid series were more favorably located in this respect than the

SECTION I.

SECTION IL.

SERIES 8 \ SERIES .C SERIES A SERIES B SERIES C

Cyenemid +Acid monium Sulfste mid+ Basie \\Cysnamid+ Basic

+Acid Phosphate Phosphate + Potash \\+ Acid. Phosphate Slag + Potash Slag + Potash.
+ Potash ers Separstely\ \+ Potash

SERIES A

as ee

SSN a AEE
Seo. oe 5

SSS

SERIES C —-SERIES_B>*
SECTION IL,

Fic. 1.—Diagram of field No. 1 located at Muscle Shoals, Ala., showing plat arrangements and treatments

for the season 0f 1921. The soil typeis Clarksvilleloam. Three rows per plat without bufferrow. Size

of plats, one-fortieth ofan acre. Theindex figures refer to the number ie of NH3, P20;,and KO
used peracre. Ac. P.= Acid phosphate; B. Slag = duplex basicslag; K = potassium sulphate; Am. S.
= ammonium sulphate; S. N.= sodium nitrate; Am. N.= ammonium nitrate; Ca. N.= calcium nitrate;
M. S. (Cl.) = mixed salt made from potassium chlorid and ammonium nitrate; M. S. (SOs) = mixed salt
made from potassium sulphate and ammonium nitrate.

ammonium-nitrate series. Plate III, Figure 2, illustrates the relative
cotton yields with the different rates of application of ammonium
nitrate.

Cyanamid was not as satisfactory a fertilizer as the other two
materials, but the results were much better than those obtained the
first year on the same plats using cyanamid in mixture with acid
phosphate. At the smaller rates of application the differences for
the two years were less noticeable, but at the equivalent of 80 pounds
of ammonia per acre the material failed to give quite as good results
as sodium nitrate. The difference was not great, however, as shown
by Plate IV, Figure 1. The retarding effect of heavy applications

at the beginning of the season was a handicap from which the plants
were never able to recover completely.

20 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

TABLE 8.— Yields per acre of cotton from Section I of field No. 1 in 1920 and 1921.

Yields of seed cotton (pounds).

ri 1920 1921
Fertilizer ratio.1 Plat.
Increase Increase
Actual. | Average.| over Actual. | Average.| over
check. check.
Series A.—Ammonium nitrate: |
116 36
Te ah eR tele mes Ape a Oe eee | Gee eee | Soda 04 eee
ie Agee eee ec {3 4 begs ts eee Hf Bopel rcs. 28: emai
2-8-4 ys 2| 4,508 yeas 19g |{ 1,016 872 15
oa nee eee ecesereseectaves see { ra ihe te , 728 54
ee RY, ee | Ga 524 |f 1,396 |\ 4 90 504
SaaS 7 Seabees ces Vim bana ea 1,048 |f 7)
; | "05 1 620 ,
Syke ume oa ye i ia fives f 1,968 844 { 1524 } 1,572 S54
Series B.—Sodium nitrate:
164 108
OOM Che tah eh Adie { 4 Dey Ble ssernseah { 1s \ (Sa A eae
0
Ca BS ee na eae { 2) pie |p bis fe... Boa (ht GME 5 eee
ae age he 2} 1,364 /\ 4 399 272 804 882 268
“ich fcacrasn heey sneene os { 21 15416 960
eed ER {3 1360 [+ 1,648 590 |{ 7°3p¢ |} 1,222 608
Le perenne PTE Err { & | AeA acta} —--4-008-1 “o-2foetee 1,874 960
Series C.—Cyanamid (with acid 8 : :
phosphate applied separately):
2 ite cap Os RR Se Oe WORE Hier alh 2a Fic 7' borer ts {oS rgee4) | 100 | pee
1} 1,504 928
De SN eae alee oor? | ale ae \ ao lf 7844) seca
CEE eT ae a 2 512 \ 1,598 244 { He 970 136
eR wie. | ee a Se 3 ae \ 1, 860 506 { von \ 1,216 432
“ole einen | Se Ca ane c Fel aes { 5 2 Oe \ 2, 002 64s |{ 708 \ peat 682

1 The term “fertilizer ratio” used in this and subsequent tables refers to the percentage of NH3, P20s, and
K20 per acre, in the order named. Applications were made at the rate of 1,000 pounds per acre.

Results with corn.—The effects of the various fertilizer treatments
on corn were quite different from those on cotton. Cyanamid pro-
duced growth corresponding to that made by sodium nitrate except
that the early retarding period was a few days longer. However,
the nitrogen became available about as soon as needed, and no per-
manent injuries were in evidence. Ammonium nitrate was very
readily available, as shown by Plate V, Figure 1. The yields are
given in Table 9. In considering the figures for the unfertilized
plats it should be borne in mind that these plats received heavy
applications of nitrogen during the season of 1919, and the effects
undoubtedly persisted during the following two years.

The differences between the three sources of nitrogen when used
as fertilizers for corn were not great when due allowance is made for
soil variations. The increases in yields obtained with ammonium
nitrate were usually larger than with sodium nitrate or cyanamid,
but the actual yields were smaller. This was because the soil was
very shallow, due to continuous erosion. Cyanamid gave practically
the same increases as sodium nitrate and seemed to be about as

effective a source of nitrogen for corn as either of the two nitrate |

forms of nitrogen.

Bul. 1180, U. S. Dept. of Agriculture. PLATE III. —

FIG. |.—EARLY GROWTH OF COTTON WITH SULPHATE MIXED SALT. FIELD 2,
SEASON OF 1921.
At left, no nitrogen, 1,090 pounds 0-S-5 fertilizer per acre; yield 540 pounds of seed cotton. At
right, mixed salt, 1,000 pounds 4-8-5 fertilizer per acre; yield 872 pounds of sced cotton.

FIG. 2.—YIELDS OF COTTON FROM PLATS RECEIVING DIFFERENT AMOUNTS
OF AMMONIUM NITRATE. FIELD I, SEASON OF 1921.

Left to right: No fertilizer; yield 64 pounds of seed cotton per acre. No nitrogen, 1,000 pounds
0-8-4 fertilizer per acre; yield 718 pounds. Ammonium nitrate, 1,000 pounds 2-8-4 fertilizer per
acre; yield 872 pounds. Ammonium nitrate, 1,000 pounds 4-8-4 fertilizer peracre; yield 1,222
pounds. Ammonium nitrate, 1,000 pounds 8-S-4 fertilizer per acre; yield 1,520 pounds.

Bul. 1180, U. S. Dept. of Agriculture. PLATE IV.

FiG. |.—GROWTH OF COTTON WITH SODIUM NITRATE AND CYANAMID (ACID
PHOSPHATE APPLIED SEPARATELY). FIELD |, SEASON OF 1920.

At left, sodium nitrate, 1,000 pounds 8-8-4 fertilizer per acre; yield 2,2(8 pounds of seed cotton.
At right, cyanamid, 1,090 pounds 8-8-4 fertilizer per acre; yield 2,096 pounds of seed cotton

Fiac. 2.—FIELD OF COTTON, SHOWING INJURY PRODUCED BY A HEAVY APPLI-
CATION OF CYANAMID DURING A VERY DRY PERIOD. FIELD 2, SEASON OF

1921.

At left, cyanamid (with basic slag), 1,000 pounds 8-8-4 fertilizer per acre; more than half of the

plants died; yield 556 pounds of seed cotton. At right, no nitrogen, 1,000 pounds 0-8-4 fertilizer
per acre; stand good; yield 424 pounds of seed cotton.

Bul. 1180, U. S. Dept. of Agriculture. PLATE V.

Fic. |.—EARLY GROWTH OF CORN WITH AMMONIUM NITRATE. FIELD I,
SEASON OF 1921.

At left, ammonium nitrate, 1,000 pounds 4-4-2 fertilizer per acre; yield 28.6 bushels. At right,
no fertilizer; yield 8 bushels.

FIG. 2.—EARLY GROWTH OF CORN WITH CYANAMID (AND BASIC SLAG).
FIELD |, SEASON OF 1921.

At left, cyanamid, 1,000 pounds 4-4-2 fertilizer per acre; yield 36.6 bushels. At right, no fer-
tilizer; yield 8 bushels.

Bul. 1180, U. S. Dept. of Agriculture.

PLATE VI.

FIG. |.—CORN GROWN WITH CYANAMID (AND CALCINED PHOSPHATE).
FIELD |, SEASON OF 1920.

At left, cyanamid, 1,000 pounds 4-4-2 fertilizer per acre; yield 27.4 bushels. At right, no fer-
tilizer; yield 11.4 bushels.

FIG. 2.—CORN GROWN WITH CYANAMID (AND BASIC SLAG). FIELD I,
SEASON OF 1920.

At left, cyanamid, 1,000 pounds 4-4-2 fertilizer per acre; yield 34.3 bushels, At right, no fer-
tilizer; yield 9.7 bushels.

ATMOSPHERIC-NITROGEN FERTILIZERS. ot

TaBLe 9.— Yields per acre of corn from Section I of field No. 1 in 1920 and 1921.

Yields of corn.

1920 | 1921

Fertilizer ratio. Plat. Grain (bushels). Grain (bushels).
nie ss } Hanae 3
ounds). crease (pounds _ [Increase

® ) al. Aver- over Actual. pee over
&ge- | check ag check

a fh a fl ff | —s a-2-

te:
Ope 920050) 7 s40 | 10.3 a ee 1,040 | 8.0 ho pscaet.
1,500] 10. if 44, ;
i nee \ 3) 130) 74 f BB feces. { 1,600 7a lf BOS fone
1 é 5.
ae { 14 2, 080 10.9 \ 13.2) 4.3 { 2,120 12.6 16.0 5.7
11 ; 17. , :
amma o Tis aii? { 15] 2,440] 16.0 } 166] 771 2,160 | 16.6 ee Pao
PAD ef 16] 2480] 25:7 \ 243] inal BOO) eel} 272/169
Series B.—Sodium nitrate:
pl) eee gt | 17] 1,600) 183] 18.3]........ | 1, 240 14.9 jays rs
2040! 18.0 ’160| 26.
O42. .....22. 22-2222 { = 1, $00 ine | 16.5 |......-. { 2/040 is | 22.9 |....-.--
2720} 21.1 2’ 400 z
a a te { ig} 2240 15.4 nay 3 2, 040 2.5 | Nabe ae a
“i a eras I , 20.9 4.4 { , 28.6 5.7
4-42 2 3) 200 30.3 30.6| 14.1 { 2640 71 | 37.1 14.2
bg ee { i¢| 2920] 309\f °° 2560 | ae! if
Series C_—Cyanamid (with
——
“at 17 C76 ist 14.8 |2..-.<-t 1,120} 8&6 ca. ee,
9| 2040] 15.4 2360 | 20.6
2 a * { Fe 1,230 call 20t.......5 { i 70 io} 15 2.
10 360 ;
142. ....-.2------+--- { 14 1, 920 86 \ 10.6) —1.4 { 2,000 11.4 \ 16. 0 5
u| 2 i "16 ;
le { 15 2, 560 16.0 \ 16.3 4.3 { 2, 200 20.6 20.9 5.4
12 ;
44-2. ..2. 22-22-22 see { 16| 3,000 elt 28.3 | 16.3 { 2280| 2.0 \f 289) 13.4

The relative percentages of grain and stover varied to a marked
extent for the two seasons. In 1920 the wet period of early spring
and summer was followed by a drought at the time of ear formation.
A heavy stalk production without the comresponding orain yield was
the natural result. Exactly reverse weather conditions in 1921
gave a much larger proportion of grain. It will be noticed also that
in Table 9, as well as in subsequent tables, there was a rather general
tendency for small nitrogen applications to produce stalks rather
than grain, particularly in 1920.

CYANAMID AND AMMONIUM SULPHATE.—SECTION Il.

This series of plats was planned primarily to determine the advisa-
bility of using cyanamid in mixture with either calcined phosphate
or basic slag. However, during the season of 1921 it was impossible
to secure sufficient calcined phosphate and it became necessary to
use basic slag on all iorientd lats. Ammonium sulphate was used,
with acid phosphate as a standard for comparison. The experiments
were conducted on the same soil used in 1919 for the time-of-applica-
tion studies. Since acid phosphate was used on the plats at that
time the later results can not be considered as an estimate of the

22 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

relative merits of the three forms of phosphorus, but merely a meas-
ure of the returns from the nitrogen applied in mixture with the
phosphorus carriers. The experiments were conducted at the same
time and in the same manner as those of Section I, previously dis-
cussed, and the data are therefore comparable.

Results with cotton.—The yields of cotton for the two years are
given in Table 10. The increases produced by ammonium sulphate
were of about the same order as those produced by the two nitrates
of Section J. Any variations may be attributed largely to factors
other than the source of nitrogen. The use of cyanamid in mixture
with either calcined phosphate or basic slag was entirely satisfactory,
as is shown by Plate VI, Figures 1 and 2, and Plate V, Figure 2.
While the yields show considerable difference with these two mix-
tures, the figures are in reality somewhat misleading. The soil of
series B was very shallow and located on the side of the hill where
moisture conditions were often the limiting factor to growth. Series
C was on lower and richer soil. It is felt that the use of cyanamid
with either of the two basic phosphates or with acid phosphate
applied separately is satisfactory and where used under exactly the
same conditions would give about equally good yields.

TABLE 10.— Yields per acre of cotton from Section II of field No. 1 in 1920 and 1921.

Yields of seed cotton (pounds).

1920 1921
Fertilizer ratio. Plat.
Increase Increase
Actual. | Average. over Actual. | Average. over
check. check.
Series A.—Ammonium sulphate: a be
AR eee alt E Ld eed {a pS see ie { 16 ) 119-1 racer
1 1, 080
OBA... on oon nent enn pes gnee No 5]. 1344 \ Uh eal eters Fr { 724 \ 660 |...-------
pe Wee ps he, a eee { §| i702 \ 1,532 320 1 Yaa |} 1,088 388
? ,
ean tcl an te oui { 3) Sugoi} ure] seal ies |} 1,246 586
4 1, 868 1,208
8-8-4......-------- +--+ +--+ ++-+-- { 8 2) 368 \ 2,118 906 { 1,712 \ 1, 460 800
Series B.—Cyanamid (with calcined
phosphate in 1920; with basic
slag in 1921): ise Ar
ODO. - 2-H poeins- ae 54Feab SET E -[57-> 3s { 256 \ sient loot e S22 { 116 \ 80, ]-~222- 22+
1 612 324
Gate acs Nes ie {. 5 Sal ae) Bees =: (SRSA cameo Leeat
SOU. {é) iif) 9] se gal ss] a
Ee cc ey pee ie Hoes heed Weta \ pap |} 788 416
4 1, 348 704
8-8-4.......--.------------------ { 8 1 792 \ 1,570 934 { 1, 028 \ 866 554
Sites C.—Cyanamid (with basic |
slag):
pond ul dpaleebe det bem (aie |e eee ea)
1 1, 066 2 | 708
0-8-4.....--.-----+- ++ +--+ 2++-+-- { 5 1, 104 \ 1,085 |.--------- { 744 \ 726 |..--------
panna ant... OR! { 2nkoohee \ 1, 419 334 { iE \ 1, 030 304
J
pein lo-genie oft 10} f 3) T30N sce] soo |f 188M aso] aaa
4 1,618 936
8-8-4.....------ +--+ +--+ 222+ +ee { 8 1) 744 \ 1,681 596 { 1, 260 \ 1, 098 372

ATMOSPHERIC-NITROGEN FERTILIZERS. 23

Results with corn.—The yields from the group of plats given in

Table 11 show increases in favor of cyanamid over ammonium

sulphate regardless of whether the former material was used with
calcined phosphate or basic slag. A portion of the increase may be
attributed to the fact that the two cyanamid series were located
on slightly lower ground than the other series. Nevertheless,
there is no doubt that under the conditions cyanamid was yess as
satisfactory a source of nitrogen for corn as ammonium sulphate.
It seems that corn is able to utilize ammonia nitrogen, while cotton
requires a large percentage of nitrate nitrogen for its best growth.

TaBLeE 11.— Yields per acre of corn from Section II of field No. 1 in 1920 and1921.

Yields of corn.

1920 | 1921
|
Fertilizer ratio. ae Grain (bushels). | Grain (bushels).
In- In-
(pounds). Aver- | crease |(POunds).- Aver- | crease
Actual. age. over Actual. age. over
chec check
ee ee
Phate:
ae 7} 980} 63) 63)... 2080) jot) 8a).
13.7 0
O42......--2. +222 \ 13 1,800 163 | 14.0 |......-. 1880 169 | 17.5 |...-.--
10 19. 4 | 2.3
142.2... 222-2... ; P| 14 2,240 16.0 | WF) 37 2,040 16.0 \ 19.2 L7
il 22.9 4 25.7 ;
242... e eee e eee 15 2,720 14.9 1g oT. +) #9 { 2,240 | 18.3 \ ae 4.5
600 | 26. 6 34.9
#42... . 2-2. ee ee eee A 16} 23480) 21.7 } ze BT) MOS { 27480 | 286 \ 31.8) 143
Series 2 pe esa ae (with |
calcined phosphate): 1
Oe aoe 5 tS WW] 1240} 14) 14}... 20] 87) 97 |e
1,560|. 6.3 880 :
O42... sees eee eee { 13 2; 360 12.6 \ 9.5 |-------- { 1,920 18.3 \ 14.0 |..-..-..
10 “0 /) 80 14
P42... 2.2.2.2. eee- { 14 2, 680 77 |p i BA 2,120 21.1 \ 22.3 8.3
1 18.3 2 25.7
P42... eesti e eee 15 2° 800 22.3 \ 7S |p IE 2, 240 25.1 \ 25.4) IL4
37080 6 160 | 30.9
#42... 12. e esses eee 16) 2340] 27.4 } 26.0] 1651 95’os0} 30.3 } 30.6 | 16.6
Series C_—Cyanamid (with
basic slag):
2 ign bo geen a WW} 110) 9.7) 97]... OF eee 8 3 ee
6 : 1,680} 17.1
O42... -..--. 2.22 2-- 13 2, 880 22.3 21.5 |-.------ { 2;160 24.6 \ 20.9 )..-.--.-
0 0} 30.3 560| 34.3
142. e testes eee 14 3,320 26.9 23.6-)° ° 71 { 2,320 29.7 \ 32.0{ 111
1 : 480 | 32.6
lia: 15 3,520 as 1 |} 24] 6.9 3640 | 366 |t 346] 137
38.3 27680 | 38.3
442... een e eee en nee { 16| 3,230] 343 } ae ee Ss 20 |. :36.6 } 37.5/ 16.6

1 Basic slag was substituted for calcined phosphate in 1921.

MIXED SALTS, SODIUM NITRATE, UREA, AMMONIUM SULPHATE, AND CALCIUM NITRATE.—
SECTION III.

This series of fertilizer experiments was carried out on the area
used during the season of 1919 for the miscellaneous crop tests. This
previous treatment did not seem to affect appreciably the results for
the following two years. |

24 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

TABLE 12.— Y%elds per acre of cotton from Section III of field No. 1 in 1920 and 1921.

Yields of seed cotton (pounds). +

1920 1921
Fertilizer ratio. Plat. :
In- | In-
Aver- Aver-
Actual.| AVet | Tease | 4e0 in-| Actual.) AVer- | crease age in-
age Spite PO age. over
check. . check. | Crease:
Series A.—Mixed salt (from | |
KCl):
milli Aeneid Sie Mae | { Be Te SIO lo eee Bae “say [221 eae
2
as oe ae ee { ; 1, O84 \ 1,040 DAI es ict { eb Sam 8 Papeete: foc)
1 ee epee rs oe Sins | 3 {| 1,052] 1,052 12 12 768 768 = =
AS a Siew ee eee eee > aE IY 4 1, 240 1, 240 200 133 972 972 196 174
4-8-6) SHC eS ee AR : aes 1,444 404 335 1, 376 1,376 600 520
920
Ge ee ee ee { 19| "S76 } 7 ROE, AAO Fr | Mieke ae |e
AS a ey ee Bes so 8 896 896 oy PSE 884 LBZ PAE eee 2
y | ee 2 So 9 1, 096 1, 096 10 ee 1,172 1,172 AAD
Series B.—Sodium nitrate:1!
Pe Bek. ge Dy een Oe Bae fo a eee
Prudschigg. fs" { rs pag | hee eee eer pol | Rae Meiers |e
EE A ee Se ee 3 900 900 94 94 656 656 156 156
a OE, Wet ts ERY Se a 4 1, 568 1, 568 762 361 940 940 440 280
Ba Bat eit strict 5 1,945 | 1,945 1,139 746 | 1,260 1, 260 760 620
ToS ORS Spain Sa eid meee ey 2 es ee po | aero a eee Se
eat WR Tae ee ee Se 8 676 676 a. | 1) 636 636 120 [Bees
= re edie TER eg cee Sel ae 9| 1,068] 1,068 5 SY Ae (er 996 996 co. as 2c ain
Series C.— Urea: : Bs dea
Oe Se et Foes oh ke 7 eon } oo i aa pr a6 2 See
oy ee REBT ON Aa) a nee ae Fg | eee
pS ER OS ye det 3| 1,268] 1,268 238 119 896 896 244 210
ey, ER Pores arene 4} 1,744| 1,744] 714 1,316 | 1,316] 664 580
Sea ee - Sa RT : oo 2, 060 1, 030 1, 030 sr if 916 916
7: are Tea { Amica og A ot Me { OL |t | Sta Aasod- cdl
FE eel ae TT edettt £5 28 - 8| 1,084] 1,084 Ue Eo eee 900 900 176
re eS ee eee re Be 9 1, 548 1, 548 0 eee 1,220} 1,220 496i) 5A
Series D.—Ammonium sul-
phate: , et, ES
gape? iteay | eee { lee ee \ Witla «Vales. ous is pve en ees
2 928
Pen awe pret { 4 me | | Re: cre lh 670 jc eee
7S: RS, Papa lpg Sie SRT Fae 3 1, 508 1, 508 602 468 | 1,176 1,176 506 442
Ee Ee Ee ee eee oe eee Bad 120) escola ee eees 826 1,260 | 1,260 590 642
Sek Ee Be ged Sa ey 5 | 2,040] 2,040] 1,134 1, 134 1, 564 1, 564 894 894
6 884 672
eae yet hee 4 a0 | 1,088 [J 28 foe---s24fs-4----- na |b. od se
Dea a RR EEG. + eet 8 1,320 1,320 $< 1 Ae eee 1,052 1, 052 3183|=> Soe
1 EE TE eae 8 ao ee seg 2 9 1, 812 1, 812 7 i bg 1, 368 1, 368 694} 2-7 7 2
Series E.— Urea:
OO $425 esate { aie \ og ae oe ee ae { “40 \ 70 juni .ic 2
2 936
peal Se yee lee { rg ae \ hy Cee? See { Oot) 80 ances: ee
0 ed a EO 3 1,228 | 1,228 392 310 976 976 436 345
Be ea Se Se re ee he tents 4 1 504 532 1, 044 1,044 504 497
ES ON AEA oh ee 412 1, 412 576 576 | 1,048 | 1,048 508 508
6 36
Tae Ae end aes erie { Pel et \ “0 Ghee ee ee { ee } oy a
EO rere eee ce ee 8 1,024 1, 024 774 (eR a Se 800 258 | 2 eee
1 Se UM oe Se Rote mee coe poe 9 1, 356 1, 356 7 1, 036 1, 036 490'|: 2h 2 ee

1 Mixed salt (from K»SO,4) was substituted for sodium nitrate in 1921. The potash content of the fertilizer
mixtures containing sodium nitrate was 4 per cent and with the mixed salt 5 per cent.
2 This plat is omitted from the averages because through mistake it received no nitrogen.
? Calcium nitrate with basic slag was substituted for urea in 1921.
Results with cotton.—Table 12 gives the yields of seed cotton for the
two years. These show considerable variations between treatments,

ammonium sulphate usually giving the largest increases. Sodium

ATMOSPHERIC-NITROGEN FERTILIZERS. 25

nitrate and urea were about as good, however. With regard to urea
it will be noticed that there was a wide variation between the yields
of series C and H in 1920. This again emphasizes the marked soil
variations and shows the necessity of disregarding small differences
in judging the value of any particular source of nitrogen. Series A,
which received mixed salt, was likewise located on a very poor area
with a shallow surface soil. Taking these points into consideration,
there seemed to be little Stieranha batiroen the fertilizing values of
urea, ammonium sulphate, sodium nitrate, and the two mixed salts.
Calcium nitrate was not as satisfactory as the other materials, prob-
ably because the nitrate-basic slag mixture became very hard after
mixing and could not be distributed properly. The data are scarcely
adequate for drawing sharp lines of distinction. The growth of cot-
ton with urea is shown in Plate VII, Figure 1, and with the two
mixed salts in Plate VIII, Figures 1 and 2.

TABLE 13.—Yvelds per acre of corn from Section III of field No. 1 in 1920 and 1921.

Yields of corn.

1920 1921
Fertilizer ratio. Plat. Grain (bushels). Grain (bushels).
(Stalks, Stal, as
a Aver- | crease |\Pounds). Aver- | crease
Actual.| “age. | over Actual.| “age. | over
check check
Series A.—Mixed salt (from
KCl):
oS ae 5 eee 2 16 oop ae B10) leccodace 1, 760 13.1 ye Ua ee Fe
il 560 | 4.6
a ee { 15} 1,440] wolf %9 |-------- { 1,920| 13.7 } 9.2 |e esas
US Se Gan se 12 2,160 8.0 8.0 —1.9 2,000 10.3 10.3 Li
Zs: be eae 5 BS a Be ty Ede 13 2, 240 10.3 10.3 4 2 200 VW 17.1 7.9
is Sa Brave Sele e 14 2,720 20. 0 20.0 10. 1 2, 560 30.9 30.9 21
Series B.—Sodium ni-
trate: 1
eee et Ce os i: 7 oh a (! 1 Co a ea A a He a RYE ee
1 ’ 700 0 3.
O42... eee eee eee { 15| 2760] 25.7 \ rie a pe ae { 2/200} 28.6 \ 20.9 '|--------
AYO begs Lee ee 12} 3520] 17.7| 17.7| —4.2] 2240] 201) o11 2
AD iS Se NSE st Imiciels «6 13 3, 480 2154 Ziel —.8 2, 360 24.6 24.6 BEY
AA Dicindinbeacce cs ck. 14 3, 720 38.3 38.3 16. 4 2, 720 SYS 37.0 16.8
Series C.—Urea:
Cee ce tmttiees wc 4 Care ans DOOM ee eke aps rape ree pS ig RE ib Eis
1 64 800 3
O42 seen essen eee { is| 22840 | 2507 |¢ 189 |----++-- { 27120) 24.6 fee:
HEA EH. 28 a eS ee 12 3, 280 14.9 14.9 —4.0 2,040 14.9 14.9 —.6
DAO ee Mk od sk 13 3, 480 PALSY i 21.1 2:2 2,320 24.6 24.6 9.1
BA Di OSL San SSS 14 3, 800 38.3 38.3 19. 4 2,640 41.1 41.1 25.6
Series D.—Ammonium sul-
phate:
Pa nrriee ky 16] 1440) 10.3] 10.3 ]........ 1,760 | 211 Pork oe
1 ’ 100 ' 1680] 8.0
O42... eee eee { 15| 2/480] 16.0 \ 14.0 |......-. { 1,720 | 16.0 } 12.0 |..-.-.--
JE | ge ee Eas Ad 12 2,360 5.7 5.7] —8.3 1, 680 9.1 9.1 —2.9
i a), ee rr 13 2, 680 9.7 9.7 —4.3 2, 120 14.3 14.3 Zo
(en Ae ae a 14 3, 200 26.3 26. 3 12.3 2, 480 32.0 32.0 20.0
Series E.—Urea: 2
SEEM ION 6} 1600] 206} 2.6]........| agi] 74] on]...
4. 1,680 | 21.7
O42... eee essen eee { 15} 3,000} 36.0 \ 30.0 |.......- { 27560 | 38.3 \ 30.0 |........
Sa eis tet h ted 12{ 3,040] 22.9] 229] —71]° 27390] 31.4] 314 1.4
te, 2 Se ae rae 13 2, 760 25. 1 20, 1 —4.9 2, 760 37.1 37.1 etek
_ Ta ag os RA a Se 14 3, 480 38.9 38.9 8.9 2, 920 45.1 45.1 15.1
Beene Nie oman doy Pow ol ly hod ant band ahh olor oodigaly

1 Mixed salt (from K2SOx4) was substituted for sodium nitrate in 1921.
* Calcium nitrate with basic slag was substituted for urea in 1921.

26 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

Results with corn.—The yields given in Table 13 again show the
wide differences in fertility between series and within the same
series. The results for series X for the season of 1920 should be dis-
carded, since these plats were located on very wet soil. During the
rainy period of early spring about half of the plants died and the area
had to be replanted. The extremely wide variations between check
plats of all of the series during 1921 were due primarily to weather
conditions. The plats were located on a gentle slope, the lower ones
being much better supplied with moisture than the upper.

It is useless to try to state the relative merits of the fertilizers, for
the reasons given. The observations during growth as well as yields,
however, did not indicate any appreciable differences between urea,
the two mixed salts, ammonium sulphate, and sodium nitrate.
Even calcium nitrate gave a good increase in yield regardless of its
slow start, due probably, as already stated, to the poor mechanical
condition of the mixture when applied. The growth of corn with
urea is shown in Plate VII, Figure 2.

The figures given in Table 13 and elsewhere show a marked tend-
ency for small applications of nitrogen to produce stalks rather
than grain in many instances. The season of 1920 was especially
favorable for a high percentage of stalks, while the reverse was true
in 1921. This was due chiefly to two factors: (1) Fewer stalks were
left per given area in 1921 than in 1920, thus making available more
food, sunlight, and moisture for each plant; (2) the wet growin
season of 1920 produced a very rapid growth and probably a limite
root system, since plenty of plant food was available in the vicinit
of the seedlings. As this supply neared exhaustion the late aril
and maturity suffered, because there was not enough nitrogen to
produce a grain yield proportionate to the large stalk production.
The lack of a wide-spreading root system left the plants at a greater
disadvantage than those which received no nitrogen. On the other
hand, during the season of 1921 the early plant growth was slowed
down because of lack of moisture. Plant development was gradual
throughout the year, and the stalks were really smaller than normal.
Plenty of rain at the time of seed formation favored a grain produc-
tion proportionate to the weight of the stalk, even with the smailest
quantities of nitrogen. These facts emphasize the importance of a
study of the best methods of applying fertilizers, for example, in the
drill, by side applications or broadcasting.

Fietp No. 2.

This field, a diagram of which is shown as Figure 2, is the one that
was planted to winter crops in the fall of 1919. After harvesting
the crops in June the soil was allowed to remain barren until the
spring of 1921, when the experiments with cotton and corn reported
on below were started.

AMMONIUM NITRATE, UREA, AMMONIUM SULPHATE, AND CYANAMID (SINGLY AND IN
MIXTURE WITH CALCIUM NITRATE).—SECTION I.

Results with cotton.—The importance of the weather conditions
in this experiment necessitates a special reference to this factor.
Planting was done near the end of a very wet period and was followed
by a prolonged period of dry hot weather. There was adequate
moisture to produce almost perfect germination, but the subsequent
drought caused the burning and death of a large number of plants on

|
|
;
|

Bul. 1180, U. S. Dept of Agriculture. PLATE VII.-

FIG. |.—GROWTH OF COTTON WITH UREA. FIELD |, SEASON OF 1920.

At left, urea, 1,009 pounds 8-8-4 fertilizer per acre; yield 1,412 pounds of seed cotton. At right,
no nitrogen, 1,009 pounds 0-S-4 fertilizer per acre; yield 736 pounds of seed cotton.

Fic. 2.—GROWTH OF CORN WITH UREA. FIELD !, SEASON OF 1921.

At left, urea, 1,00) pounds +4-2 fertilizer per acre; yield 41.1 bushels. At right, no nitrogen, 1,000
pounds 0-4-2 fertilizer per acre; yield 24.6 bushels.

Bu!. 1180, U. S. Dept. of Agriculture. PrAne Vie

FIG. |.—EARLY GROWTH OF COTTON WITH SULPHATE MIXED SALT. FIELD I,
SEASON OF 1921.

At left, mixed salt, 1,00) pounds £S-5 fertilizer per acre; yield 996 pounds of seed cotton. At
right, no nitrogen, 1,000 pounds 0-8-5 fertilizer per acre; yield 528 pounds of sced cotton.

FIG. 2.—EARLY GROWTH OF COTTON WITH CHLORID MIXED SALT. FIELD I,
SEASON OF 1921.

At left, mixed salt, 1,000 pounds ‘4-8-6 fertilizer per acre; yield 1,172 pounds of seed cotton. At
right, no nitrogen, 1,000 pounds 0-8-6 fertilizer per acre; yield 544 pounds of seed cotton.

Bul. 1180, U. S. Dept. of Agriculture. PLATE IX.

Fic. |.—EARLY GROWTH OF CORN WITH SULPHATE MIXED SALT. FIELD 2,
SEASON OF 1921.

At left, mixed salt, 1,000 pounds 1-8-5 fertilizer per acre; yield 38.5 bushels. At right, no fer-
tilizer; yield 33.7 bushels.

FIG. 2.—EARLY GROWTH OF CORN WITH AMMONIUM CHLORID. FIELD 2,
SEASON OF 1I92].

At left, ammonium chlorid, 1,000 pounds 1-8-4 fertilizer per acre; yield 17.7 bushels. At right,
no fertilizer; yield 6.3 bushels.

Bul. 1180, U. S. Dept. of Agriculture. PLATE X:

FIG. |1.—EARLY GROWTH OF COTTON WiTH DOUBLE SALT. FIELD 3, SEASON
OF 192).

At left, no fertilizer; yield 120 pounds of seed cotton per acre. At right, double salt, 1,000 pounds
2-8-4 fertilizer per acre; yield 763 pounds of seed cotton.

FIG. 2.—GROWTH OF CORN WITH DOUBLE SALT. FIELD 3, SEASON OF 1920.

At extreme left, no nitrogen, 1,000 pounds 0-4-2 fertilizer per acre; yield 19.6 bushels. Center
(1 row), no fertilizer; yield 17.1 bushels. At right, double salt, 1,000 pounds 4-4-2 fertilizer per
acre; yield 33.9 bushels.

ATMOSPHERIC-NITROGEN FERTILIZERS. 27

certain areas. However, it was only where cyanamid was used that
enough plants were killed to affect the stand appreciably. At the
rate of 40 pounds per acre of ammonia, as cyanamid, the injuries were
temporary, but with 80 pounds about half of the plants were killed,
as is shown in Plate IV, Figure 2. Where calcium nitrate was used
with cyanamid the extent of injury depended almost wholly upon
the amount of cyanamid used.

4 — BS K*)\ (—— B57 —— PEK

oe. - - | (an [Ures®” = = i)

eqn? = | (eee fama” == | [Urea® = | Amn

Pe 9 eee ee | eee

SHEE : Urea

Toym® ~~ | (eee

pacer = | ee ous. | fara - | oer

4 Zn Sea x

| iy . sl] | &

3 3 [_— —— 3414/8
«i : —— =_ %1- b
& ACP? RINE | S

7] 9 2 s >

10 S

‘an
4 NOS ¥

0

x

G

s
a

a = _
(33) (nS? = KF) (MS6Q)™ ~ A*)
ei Ue dmcl™ AS = MSSGF° _” _K*?
Fig. 2.—Diagram of field No. 2 lo- [—__— —]} (— — — }
cated at Muscle Shoals, Ala., show-
ing ae 5 yes ang, pus
ISHAS LOT Hb SEAeOE |B . 2 . oid
soiltypeisColbertsiltloam. Three 2422 — LSC A 4
rows per plat without buffer row. 24"C" > _= Jo |#5.Cy" _- _H7* |x, o:
at of aah one-fortieth of fy acre. 2. —— ne: AEA |S See N
Theindex figures refer to the num- oer” Keto | —— ac Pe Ho
ber of a of ae 20s Bui O1s.G = = Sr eae S
K.0 used per acre. Ac. P.= Aci EY RPA ee y

phespiate: B. Slag = basic slag;

potassium sulphate; Am. S 1S. ”
= ammonium sulphate; Am. N.= {— — —}]
ammonium nitrate; Ca. N. = cal- —— ee” 1) | ae 4

cium nitrate; Cyan. = cyanamid;
Am. Cl. = ammonium chlorid; M.
S. (Cl.) = mixed salt made from
potassium chlorid and ammonium
nitrate; M. S. (SOs) = mixed salt
made from potassium sulphateand — —
ammonium nitrate. ‘ |
The soil variations were a greater factor in determining yields
than the fertilizer treatments. On the ammonium-nitrate series
the soil was the most uniform and best adapted to cotton of any.
On the other hand, the soil of series B and C was too heavy and com-
pact for cotton and too fertile to give satisfactory results in a fertilizer
experiment. On these two series early growth was slow, while the
late growth was unusually rapid. The result was a heavy stalk
production, poor fruiting, and maximum boll-weevil injury, especiall
with the largest applications of nitrogen. The soil of series D and
was exceedingly variable, one side being very productive and the

other the poorest in the field.

7 =,

—-

ee
ys

pss

Se OO

ae ~
ee
ih gmt

28 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

TABLE 14.— Yields per acre of cotton and corn from Section I of field No. 2.

[In series D tests marked with a star (*) cyanamid and calcium nitrate were used in equal proportions
pe eren marked with a dagger (+) the proportions were 75 per cent cyanamid and 25 per cent calcium
nitrate.

Yields of seedcotton(pounds). Yields of corn.

8-8-4
Series E Pi hg ed geaaen
(with basic slag):
0-0-0

s S a Grain (bushels).
Fertilizer ratio. 3 o4 | os =| :
a 0 2S a3 AS) Be & |S, 71 2
a | @ | $3 | ss qa | € |sse!] #2
3 © 5 id a 8 |£53| &3s
© > A < 3 S > god £5
< < = re ae tee Foal |
Series A.—AMmonium
nitrate:
On aa eee eas 4 60 BOO ete i ina F300 | Se Tt OB |. ceciae el
Ue eae npesenerc Seen 988 LU) aes Fy po ae \ De Fl eee a
a a aa ES 760{ 760| —50|....... 2,680 | 33.7] 33.7] 0
BER Bie Lone ts tecagttons 1,048] 1,048] 238]....... 2560 | 84:91) 34:91 A257 o,. Z
BAe Foner k ariey tots 1,508 | 1,508] 698 ]....... 2,720| 30.4|° 39-4) 5.7 ].......
S-SAe bocances hee 1,560 | 1,560 3 i legos ae 2,920) 41.1] 41.1 = A Soe hy
2M E Neocncens Srhohones Peet B88 [ote eee 2,680) 37.1 } 39.4 mi eer
ee ae ee 836 836 22 36 3, 040 calor a | RGN Wheto le iat aa
2-8-4 72| 772) —86| 76 Poot as | gee | ces) we
ASR RE ga 984 | 984] 126] 412 3,040| 41.7] 41.7| 2.3 vee
Pe a eee sitet swoeS 1,460 | 1,460] 602] 676 3,040] 41.1] 41.1] 1.7 4.6.
DDoS eer ane te) ou CS) Recaianaeesal (el: sip 2040 | Sar) 21, Ut. | soe
ra Ui eheseranal sana’ Paget Lee Meee We ne Pabh cate } 12,8 | 2 eae
i "CE ae 1,088 | 1,088} 156 }....... Ty 18 MS Te lle Bi eS bod re
7 IO a recat Wier rae 1,308 | 1,308] 376 |......- 20001474 | 17.4) “paplte
SBA ee So eee 1288 Tt, 28 Toe oe 2,320| 26.9| 26.9] 131].1.....
FHS BIS br ihe 04 984 a ees 24805) S36.0 | SOO See.
[Lars 8 er oparaae parr 628 BIO Fins own ere] = eae wes ri oe Bie \ 20.6 |s tawsele sl... <s
1S a eae 1, 044 1,044 | 244 200 2,200} 14.9) 14.9] —5.7]) —1.2
BW Menta 60 8 || 22.31 ke ;
LaG-lt lacugicceeeen tary 952| 952] 152| 254 2) 400 33.7 ge igs | i
serie or nkaaranaeg ea 1,152 | 1,152} 352| 202 2,720| 36.0] 36.01 15.4] 18.8
sulphate:
O-D-D) . aacousrpeae eet 898002 bere 2:86") S684 38.3% loo
OB jarcorrerst epee te Pepe? | ocecoe| Svat Pion aay | te? (cies
a Pgeneeee fos | fos | de occ am | 849) S83 | te boc
[ tener es rank. oe apa 38. ; RP en
RL Leo peceuencuete 1,012] 1,012} 270 |....... Pg iyh Mies rt WS le, Ce fy Woke
3 i bee a icra BIZ \| BIZ |e BO Aeereave SO as |. Skt, we een
Dad ie etnag teres i ead Cee coer rie ae eee eee
4 Dial ee ok Mr RS oS ea at Ch
PTO. cca atwialaowonsoccce , Fi le Te, 4, 2
BREN oe fame 920] 920] 154] 212 2,440! 31.4| 31.4] 9.7 8. :
PR atlel saa 8th heros « 648 | 648] —118} —174 2,880} 40.6| 40.6| 18.9] 11.9
Series D.—Cyanamid and
calcium nitrate (with
basic slag):
TE a ee a ea map a hen 1 Oy Ns oc aR
Fa Tap ite see ier a a rere ret Be teed igs desconeclodee é
WRAY poze Seber 684| 684] 206|.....-- FSF lg Ol ge eM il fig Sle
2-84 EAS PEIN AS 5 BD GAD fo BGR eee oa ae 2.5201 30.9| 30.9] 12.6|.......
a © eee 808 4° 808 |....330.). 0025-2 2720 '| '34.9'|- 34-9 | 16.6].......
Vials aia obs eT 728 728 | © 250 |... 2. Oat lek MC Ur at SR oy tle
0-84... 2-2 eee e eee B62 pa 8S cleo enledeess Fy a0 | aed \ 28.9 wet eree|ene seen
ELT AO en el ele 404 1.7404 | 1164). Bee 2,400| 21.1) 21.1 ]'—7.8 12.2...
LOE) SID Res 524 | 694-1 236 [isc iak. 9/560'| -80.3:1 80:84 5 castulsaee
BRAD sca ier evetay) cy 616))).:616'1)) 3282s. 1k: 2,720 | 38.9] 389) 10.0].......
5 vinta Sank enone 528| 528{ 240|....... 2.840'| 86.041. 3606:| - We 7 tages.

ATMOSPHERIC-NITROGEN FERTILIZERS. 29

The yields are given in Table 14. Ammonium nitrate produced
good increases and was an entirely satisfactory nitrogen carrier for
cotton. The yields with the various rates of application of urea and
ammonium sulphate were unsatisfactory because of the soil, as pre-
viously pointed out. The two materials affected growth and matu-
rity in the same manner. The yields with urea were slightly better
than with ammonium sulphate, but the differences are not significant.
The yields with cyanamid or cyanamid and calcium nitrate were
considerably below those on the other three series, due largely to the

oorer soil. In addition, the retarding effect of cyanamid did

irectly lower the yields and increased the boll-weevil injury. The
failure of calcium nitrate to improve the mixture is contrary to
results reported in the literature.

Results with corn.—Because of dry weather a decided injury was
noted on all of the corn plats receiving 80 pounds of the ammonia
equivalent, regardless of source. Cyanamid was more injurious than
the other materials, but no more so than the same quantities of
nitrogen supplied in a calcium-nitrate-cyanamid mixture. The
materials were all equally available so far as observations could de-
termine. Table 14 gives the results.

A consideration of the yields on the check plats of this entire
section of the field emphasizes the marked irregularities of the soil.
Variations of 100 per cent or more are not uncommon between
check plats of the same series or between corresponding check plats
of two different series joined end to end. Small differences between
treatments are therefore unimportant.

The ammonium-nitrate series of plats was located on the most
productive and wettest portion of the field. Consequently, the
yields on all plats were good, regardless of fertilizer treatment. The
increases produced by ammonium nitrate were slight, and the data
do not permit any conclusions other than to say that the material
gave responses similar to urea and ammonium sulphate.

The value of the yields with urea are likewise minimized by irregu-
lar soil conditions, but since the fertility was much lower than on the
ammonium-nitrate series the increases produced by the urea were
much more marked. Taking into consideration the check plats,
urea seems equally as good as ammonium sulphate.

Cyanamid, either alone or with calcium nitrate, gave very good
increases in yields except where the soil was already so rich that the
fertilizer was ineffective. Neither the observations during growth
nor the final yields showed cyanamid to be inferior to the other
nitrogen carriers. The mixture with calcium nitrate gave larger
increases in yields in some cases than cyanamid alone, but the soil
was somewhat poorer.

AMMONIUM CHLORID AND THE MIXED SALTS.—SECTION Il.

Results with cotton.—The relative values of the two mixed salts
and ammonium chlorid, as shown by the figures in Table 15, are
pocually the same. The largest increases in yields were produced

y the chlorid mixed salt, ammonium chlorid being second and the
sulphate mixed salt third. It will be noted, however, that the chlorid
mixed salt was used on the poorest soil. The actual yields were
usually smaller with this material than with the others, but since the
check plats were low the increases were comparatively larger. The

30 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

wide variations in fertility and the boll-weevil damage makes the
i shght differences insignificant. The results do not justify the makin»
| of any distinctions between the merits of the three sources of nitrogen.

Undoubtedly they are all very readily available, as is shown by Plate
III, Figure 1.

| Results with corn.—The yields of corn given in Table 15 show just

| as inconclusive results as with cotton. The soil of series A and B was
so fertile that the increases produced by fertilizers were insignificant.
The yields on series C were somewhat lower than on the other two,
due to the poorer soil, but the increases over the checks were quite
good. Ammonium chlorid seemed to be an entirely satisfactory
source of nitrogen. No conclusions can be drawn from the results
with the two mixed salts. Plate [X, Figures 1 and 2, shows the rapid-
ity with which these materials are utilized by corn.

TaBLE 15.— Yields per acre of cotton and corn from Section II of field No. 2.

Yields of seed cotton Yields of corn

(pounds).
r
Grain (bushels).
Fertilizer ratio. Plat. Plat.
In- Aver-
Fae Aver- | crease age in- ( mane Tit rn
ual. age. over crease. poun SS. Aver- crease ver-
check. Actual. age. | over age in-
check. crease
Series A.—Mixed salt
(from K2SOx):
62020 31:9..H2. 16 580 580 ee TO 6 2, a 33.07 |) ME. ONE oe
11 16 1 30.3
0-8-5. .....-.---- { 15| 634 |f 700 |-------]------- { 5| 2,840 38,9 \ 34.6 ee eee
1S-5: Svea ste 12 by 828 [ie-S28 We 2284). Leta: 2 2, 960 32:0;/132 0: SR 64larye
11k 1 ee Ra 13| 756| 756 ee eee 3 2,640 5A es een er
ees tLs. ALG. 14 | 1,000 | 1,000 | 300 ]....... 4 Dus 37-1 37/1) Sarg PAvet
15| 684 5 38.9
0-8-5. ...-...-.-- 20 | 396 |f 940 |-------|------- { 10! 3,000 36, 6 \ 37.8 |...----|-------
Nese. es 17| 764] 764| 224] 176| 7 2,960 38.3] 38.3 2519 Sa
al Se ae 18} 580] 580 40 48| 8 2, 960 39.4] 39.4| 16 “f
Ea Dae 491| ig7o"l-Ke72 gepllt Breet tp 3, 120 44.0| 44.0] 6.2 4.4
Series B.—Mixed salt
(from KC1):
OO Retert cael 1 B40°|1 1840s Reels Poe 6 Bis 22/91) 122-9) Se
11 | 460 1 40.0
0-8-6. .-....----- 15| 408 \ 434 |..-.---|-.----- { 5| 2/400 26.3 \ 33.2 ee oe
aa nes 12| 516] 516 rv ieee 2 2,640 35 A dy Sh. 4: bry Dadi gees
| 7a” Shas Sone Pe 13° 1660" 11 600.1" 298" (ease 3 2, 880 36.61 SB Se eee
TE are ee ee 14| 764] 764 Oilo, sd 4 Apr 35.4 S514 NTs Bose
15 | 408 5 6.3
eae 0-8-6. .---------- 20| 672 \ 540 |-------]---22-- { 10| 27480 14.3 \ 20.3 eed oe
PER lies Rie 17| 616] 616 76 TOA Vz 2,440 20.6} 20.6 3 1.3
| F626 or 18 PO 1 8201 280" eases 2, 520 20.0.1 20:01) —=:3 1.6
7 ay ie at a 19 | 1,076 | 1,076] 536] 433] 9 2,920 26.91 26.9] 6.6 4.4
Series C.—Ammo-
nium chlorid:
iy ies Se 164 GB I SRG. baci necelle ck toe 6 1,040 6.3 | 6.3 )|. <wacec epee
11 204 1 1 16.
O-S-4........---- 15| 748 \ 476 |..-----|---++-- { 5| 2,120 9,7 |f 18:2 |-------|-------
VE ae EAR el ad had le SD tata 2 2 2,320 14, Os OS aor eee
ee rte! ica TP Rees bot ne bn Ie ew 3 2,360 19, 4 589e 4/02, Gao
| i ae 5 14 952 O52: |) 0476 Nr EEE : 2, 7a ane a AR Wa te
15 48 9.
| 7 ey aa 7 TB eseegSll aa aide face © { 10 19.4, fi? |-soe sega
ye ee 17 | 1,068 | 1,068 | 182 75| 7 2, 200 17-72( Me. 7" | Mes 4.0
Fm ae SRE ag 18 | 1,048 | 1,048 | 162 149} 8 2, 560 22.9.| 22.9 | 11.5 8.9
APSA AMEE NAS Yh 19 | 1,120| 1,120] 234] 355| 9 2,720 35, 1° | "25 tee | eee
|
Fieip No. 3.

| This field, which was located quite near field No. 2, was used for
| experimental purposes during the seasons of 1920 and 1921. The
| soil was rather low and very widely different in productiveness on

ATMOSPHERIC-NITROGEN FERTILIZERS. 31

garious portions of the plat. It was well suited to corn but too
sempact for the best results with cotton. The nitrogenous fertilizers
used were ammonium sulphate, ammonium chlorid, double salt,
ammoniated superphosphate, ammonium phosphate, and cyanamid.
The plat arrangements are shown in Figure 3.

Results with cotton.—The yields of seed cotton for the two successive
seasons are shown in Table 16. These show a decrease of about
10 to 30 per cent on the average for 1921 as compared with 1920,
due to the dry weather and the boll weevil. The latter injury was
rather uniformly distributed over the field and for the most part
limited to the late crop. Consequently, the injury was greatest on
those plats where the cotton was slowest in reaching maturity. These
were the unfertilized areas and the plats receiving the largest applica-
tions of nitrogen, especially cyanamid.

Z—~ CORN. COTTON.
Da) SECTION ZZ. SECTION T. SECTION I. SECTION I.

a —
= :

a qo ” -
” oy e.
PS
7B Gyen.™
[Ss es | SS eee
. & eee | we ee
i ————— = ~ - ee eS .- _ t

Fic. 3.—Diagram of field No. 3 located at Muscle Shoals, Ala., showing plat arrangements and treatments
for the season of 1921. The soil type is Colbert silt loam. Three rows per plat with buffer row. Size
of plats, one twenty-fifth ofan acre. Theindex figures refer to the number of pounds of NHs, P20;, and
K:0 used peracre. Ac. P.= Acid phosphate; K = pepsin sulphate; Cyan. = cyanamid; Am. S.=
ammonium sulphate; Am. Cl. = ammonium chlorid; D. S. = double salts; Am. Sup. = ammoniated
superphosphate; Am. P. = ammonium phosphate; B. Slag = basic slag.

The increases in seed cotton produced by ammonium sulphate and
double salt were of about the same magnitude, the yields with both °
materials increasing as the food supplied increased. On the other
hand, ammonium chlorid showed opposite results for both seasons,
the largest yield being obtained with the smallest nitrogen treatment.
These plats were located on soil that seemed to be quite uniform.
This would indicate that under the conditions of this test the chlorid
ion was toxic when used in large concentrations and stimulating at
the smaller rates. The responses of cotton to double salt and
ammonium chlorid are shown in Plate X, Figure 1, and Plate XI,
Figure 1, respectively.

e ammonium phosphate and ammoniated superphosphate plats
of Section II were located on soil that was too rich in nitrogen to give
large responses to additions of this element. Phosphorus was some-
what deficient, however, and its use largely blotted out the effects
of the nitrogen. The effects of ammonium phosphate and ammo-
niated superphosphate on growth corresponded to those noted with

32 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

ammonium sulphate, and it is believed that the materials are of
about equal value as nitrogen carriers. The early responses are
shown in Plate XI, Figure 2, and Plate XII, Figuresl1 and2. ~

TABLE 16.— Yields per acre of cotton from Sections I and II of field No. 3 in 1920 and
1921.

Yields of seed cotton (pounds).

ais 1920 1921
ertilizer
Treatment. ratio. Plat.
In- In-
Aver- | crease Aver- | crease
Actual. age. over Actual. age. over
check. check.
Section I: : oe be
No fertilizer. ..........022002e000- o-0-0|f 7] $73 |} 263 |..------ aS {> 108 jae
No nitrogen 2: .2.2..2.2e 0-84 { ra ice) ee bee ot ky ago “| Baae
2-8-4 3 850 850 300 833 833 343
Ammonium sulphate...........- 4-8-4 4/ 1,045] 1,045 495 | 1,018 | 1,018 528
8-8-4 5| 1,250] 1,250 700 | 1,080] 1, 590
ae 7 170 123
Wiploktilinarce eee) o-0-01 bb ae \ org Wg a only amet ae
Mmmirmigen. <0 a 0 So a 0-S4 Ni “5 iz Sl ape es ” S74 St
2-8-4 8 | 1,230} 1,230 587 948 948 474
Ammonium chlorid.............- 4-8-4 9} 1,125] 1,125 482 783 783 309
8-8-4 10} 1,088] 1,088 445 715 715 241
ae 12 305 if 120
No fertilizer............-.2--2---- cot | 22 \ is ke ae ret ae os gl
INO NitTehONE Ss 2 rss oe. oa 0-8-4 i; nee CEB ree Sans ee a8o |S 3s Ae
2-84] 13] 1,050] 1,050 439 763 763 280
MWOUD Le Sabre acme eee ese Sete e 4-8-4 14] 1,075 | 1,075 464 925 925 442
aS acs 8-8-4 15}. 1218:|--45218 607 | 1,083 1,083 600
ection IT:
NOMMirOPeN 2 62a ass ee c c acne 0-5-4 Lf 1,008 0 00a 745 (C's aoe ok
Ammonium sulphate............ 2-5-4 2] 1,050] 1,050 42 735 735 —10
Ammoniated superphosphate... - 2-5-4 3 805 805 | —203 553 503 —192
Wo mitroren ose ce 9 see 0-10-4 5 643 G43 i ween se 300 300" |S2 Saeee
Ammonium phosphate..........-. 2-7-4 6 943 943 300 608 608 308
Ammoniated superphosphate....| 410-4 4, 1,125] 1,125 482 868 868 568
Novertilizer ios ck este! 0-0-0 10 388 5°52 9 nee Be 108 WOS.iy ese
No miirOren <5 2o8 hae Stee 0-13-4 Ooi) Ey O4Siha hy OsSai. £07. 2s 620 O20 nhc
Ammonium phosphate........... 4-13-4 7 | 1,223 | 1,223 175 890 890 270
Ammonium sulphate...-........ 4-13-4 8| 1,425] 1,425 377 958 958 338
No fertilizer sj. .c..00 jigs $3802 0-0-0 | 10 388 ct eee 108 19; I 2. -
No nitrogen (acid phosphate)... .. 0-8-4 11 668 668 280 483 483 375
Nonitrogen (calcined phosphate)!. 0-8-4 12 633 633 245 433 433 325
a1: 10 388 108
Woffertilizar <<... 2-2. 0-0-0 { A apse \ 2 a eae a \ 198 |e
No nitrogen (calcium phosphate). 0-8-4 { i ae \ BIS 522 sae { a \ 4695] 5. cass a
. . . 2-8-4 13 793 793 220 618 618 149
Tet) ee caleined: phos: 4-6-4] 14], 335] “835 | 252] " ess] |! 655 | 236
pide Tazth LOCAL 8-84] 15| 715| 715| 142] 568} 568 99

1 Basic slag was substituted for calcined phosphate in 1921.

Cyanamid gave low yields in both years and was not as satis-
factory a fertilizer as any of the other materials. The plants were
very green but failed to grow rapidly or form large numbers of bolls.
Nitrification was probably slow in this heavy soil and dicyanodiamid
production was favored. It is believed that the poor yields with

cyanamid can not be attributed to the use of basic slag or calcined

phosphate.

890, U. S. Dept of Agriculture. PLATE Xl.

FiG. |.—EARLY GROWTH OF COTTON WITH AMMONIUM CHLORID. FIELD 8,
SEASON OF I921.

At left, no fertilizer; vield 123 pounds of seed cotton per acre. At right, ammonium chlorid,
1,00) pounds 2-8-4 fertilizer per acre; yield 948 pounds of seed cotton.

FiG. 2.—GROWTH OF COTTON WITH AMMONIUM PHOSPHATE. FIELD 3,
SEASON OF 192].

At left, no nitrogen, 1,000 pounds 0-10-4 fertilizer per acre; yield 300 pounds ofseed cotton. Center
(1 row), no fertilizer; yield 165 pounds ofseed cotton peracre. At right, ammonium phosphate,
1,000 pounds 2-7-4 fertilizer per acre; yield 608 pounds of seed cotton.

Bul. 1180, U. S. Dept. of Agriculture. PLATE Xl

FIG. |.—GROWTH OF COTTON WITH AMMONIUM PHOSPHATE AND AMMONIUM
SULPHATE. FIELD 3, SEASON OF 1921. |

cotton. Center (1 row), no fertilizer; yield 285 pounds of seed cotton. At right, ammonium

i

At left, ammonium phosphate, 1,00) pounds 413-4 fertilizer per acre; yield 890 pounds of seed
sulphate, 1,000 pounds 4-13-4 fertilizer per acre; yicld 958 pounds of seed cotton.

4

FiG. 2.—EARLY GROWTH OF COTTON WITH AMMONIUM SULPHATE AND AM-
MONIATED SUPERPHOSPHATE. FIELD 3, SEASON OF 1921.

At left, ammonium sulphate, 1,000 pounds 2-5-4 fertilizer per acre; yield 735 pounds of seed cotton.
Center (1 row), no fertilizer; yield 188 pounds of seed cotton per acre. At right, ammoniated
sunerphosphate, 1,000 pounds 2-5-4 fertilizer per acre; yield 553 pounds of seed cotton. (Soil
somewhat poorer on this plat.)

Bul. 1180, U. S. Dept. of Agriculture. PLATE- XE.

Fic. |.—GROWTH OF COTTON WITH UREA. FIELD 4, SEASON OF 1920.

At left (1 row), no fertilizer; yield 624 pounds of seed cotton per acre. At right, urea, 1,000 pounds
4-8-4 fertilizer per acre; yield 1,164 pounds of seed cotton. (Yields are for 1921 season.)

FIG. 2.—GROWTH OF CORN WITH AMMONIUM SULPHATE AND AMMONIUM
PHOSPHATE. FIELD 4, SEASON OF 1920.

At left, ammonium sulphate, 1,000 pounds 4-13-2 fertilizer per acre; yield 26 bushels. Center
(1 row), no fertilizer; yield 16.3 bushels. At right, ammonium phosphate, 1,000 pounds £13-2
fertilizer per acre; yield 24.9 bushels

Bul. 1180, U. S. Dept. of Agriculture. PLATE XIV.

Fic. |.—YIELDS OF CORN WITH AMMONIUM NITRATE. FIELD 4, SEASON OF
1920.

At left, no nitrogen, 1,000 pounds 0-4-2 fertilizer per acre; yield 32.6 bushels. At right, ammonium
nitrate, 1,000 pounds 2-4-2 fertilizer per acre; yield 50.6 bushels

FiG. 2.—YIELDS OF CORN WITH AMMONIATED SUPERPHOSPHATE. FIELD 4,
SEASON OF 1920.

At left, no nitrogen, 1,000 pounds 0-10-2 fertilizer per acre; yield 18.6 bushels. At right, ammo-
niated superphosphate, 1,000 pounds 4-10-2 fertilizer per acre; yield 33,4 bushels.

ATMOSPHERIC-NITROGEN FERTILIZERS.

33

The comparisons between acid phosphate and calcined phosphate
-as sources of phosphorus showed a small difference in favor of the

former.

This difference was in evidence to a slight extent during

growth, the calcined phosphate being somewhat slower to stimulate

growth.

TABLE 17.— Yields per acre of corn from Sections I and IT of field No. 3 in 1920 and 1921.

Ferti-
Treatment. lizer |Plat.
ratio.
Section I:
No fertilizer..... 0-0-0 { :
No nitrogen..... 0+-2 { 2
Ammonium sul- ee i ;
ae 4-4-2 5
on | 7
No fertilizer..... 0-0-0 { 12
No nitrogen ....| 04-2 { a
Ammonium Res A
chliorid ee ee ene 4-4-2 10
No fertilizer..... 0-0-0 | e
No nitrogen..... 0-+2 i a |
142) 13 |
Double salt..... 242 14)
4421] 15|
Section IT: |
No nitrogen..... 0-5-2 1
Ammonium sul-| 2-5-2 2
phate.
Ammoniated su-| 2-5-2 3
perphosphate.
No nitrogen..... 0-10-2 5
Ammonium | 2-7-2 6
phosphate
Ammoniated su-| 4-10-2 =
perphosphate
No fertilizer... 0-0-0} 10|
No nitrogen..... 0-13-2 9 |
Ammonium | 413-2 7
phosphate.
Ammonium sul- | 4-13-2| 8 |
phate.
No fertilizer..... 0-0-0 | 110
No nitrogen] 042) 11
(acid phos-
phate).
No nitrogen | 042)| 12
(calcined phos-
phate).i
No fertilizer... .. 0-0-0 { =
No nitrogen (cal- 'f 12
cined _phos- |+ 0-4-2 16
phate)
Cyanamid (with |( 142] 13
calcined phos- |{ 24-2| 14
phate).1 442) 15

t.bo.bO.ty bo
Be

we Ne Ne ee

De O 10
Sasss

bo WWrRD ED woo
3 '
Oo

Ph pe eae
HESS BSass

No WNNKRE Ne

Sel Oot
e eco
x s

“

Yields of corn.

1920
Grain (bushels).
| | _ Stalks
| i pe
Aver- | crease | (pounds).
| Actual. age. | over |
check.
} {
40.4 |p 281 |-------- { 2000
33.9
39.6 |} 36-8 |-------- { 27300
43.21 43.2 6.4| 2,300
48.2| 48.2] 11.4 2, 625
54.6| 54.6| 17.8 | 2,725
40.4 2, 000 |
16.3 \ 28.4 |......-. { 1,325
39.6 If 23300 |
io. |f 22-8 |------=- i 1,700 |
42.5| 42.5] 12.9 2) 175 |
44.6| 44.6] 15.0 2, 200 |
38.2| 38.2 8.6 2,500 |
16.3 1,325 |
19.6 \ 18.0 |......-. { 1, 250
19. lf 1,700
19.6 \ 19.6 |........ { 1,750
$75 (00) 9% Ht 2. del 4 1, 100
2.3} 24.3 4.7| 1,900
33.9] 33.9] 14.3 | 2,075 |
ey ee OF od eee | 2,900
47.1| 47.1 1.0} 2,750
43.2} 43.2| —2.9 2, 525 |
ere Gee aaa 2,075 |
Bt 339 | 7.2 2,050
37.5| 37.5| —2.9 2, 800 |
Dh eT NS 1, 800
BS 48. He 2, 200
46.8| 46.8 2.9 2, 225
45.7| 45.7 1.8 2, 450
oye ee AC SER 1, 800
37.9| 37.9 0 1, 950
SF 3027 #72 2, 000
37.9 1, 800
33.6 \ 35.8 |......- { 1) 825
30.7 2,000
oe \ 25.6 Jone { 3 900
36.4| 36.4 .8 2, 100
ASH” Shel 5.5 2,025
48.6] 48.6| 13.0 2,575

1 Basic slag was substituted for calcined phosphate in 1921.
52765°—24—Bull. 1180-3

1921

Grain (bushels).

, In-
ver- | crease
Actual. age. over
check.
30.7
32.5 31.6 eetene .
32.5 f 920 |-.--.e.
22:1} SLi eet
40.7| 40.7| 87
43.6| 43.6| 11.6
32.5
9.3 pO o9 earns
ied | eon eee
28.6] 28.6| 6.3
32.9| 32.9| 10.6
36.1] 36.1] 13.8
9.3 |
13.6 \ 11.5 |.......
ae PeeLisee
A231; | doer e
17.9| 17.9| 6.0
26.1} 26.1] 14.2
cy Ol ie BP
45.4| 45.4 | —5.3
38.6] 38.6 | —12.1
29:05 |-) am owe
31.8 |; 3L3 | 26
40.0} 40.0] 11.8
36.1) 36.1 |.......
16.|"" 33.6, ei te us
38.2| 382| 4.6
35.0] 35.0] 1.4
a6. |” apie | eee
32.9} 32.9 | —3.2
27.5 | 27.5 | 286
36.1
Br |} 88:6 |u--a-ne
27.5
a5 7 [-apeleeee
35.0] 35.0] 3.4
37.1). 3011 7 oS
45.0] 45.0| 13.4

34 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

Results with corn.—Table 17 shows that the increases in yields
produced by ammonium chlorid and double salt were of about the
same order as with ammonium sulphate. The soil of this section
lacked uniformity, the yields from the check plats varying from 9.3
to 32.5 bushels for the second year. Hence, no accurate quantita-
tive comparisons can be made between treatments. Ammonium
chlorid seemed to be slightly toxic the first year at the largest rate
of application but gave strictly normal results the second year, the
yields increasing as the nitrogen supply increased. Plate X, Figure
2, shows the marked contrast in the growth of corn with and without
double salt.

The fertilizer tests comparing ammonium phosphate, ammonium
sulphate, and ammoniated superphosphate were unsatisfactory
because the natural fertility of the soil was considerably above the
average. No conclusions can be drawn. Cyanamid produced unusually
good increases in yields considering that the soil was very fertile.
It was not injurious even when applied in the row at the rate of 40
pounds of ammonia. The results compared very favorably with
those obtained in Section I with ammonium sulphate. Again, it has
been shown that corn can utilize cyanamid nitrogen under conditions
where it is largely unavailable for cotton.

Fretp No. 4.

This field, a diagram of which appears as Figure4, was used for experi-
mental work during the seasons of 1920 and 1921. Cotton and corn
were grown both years, but a combination of late planting and an
unusually bad attack of boll weevils resulted in practically no cotton
for the first year. These results are omitted from this report. The
sources of nitrogen used were ammonium sulphate, urea, ammonium
chlorid, ammonium nitrate, ammoniated superphosphate, ammo-
nium phosphate, cyanamid, and double salt.

Results with cotton.—The extremely dry weather during the first
part of the growing season undoubtedly played an important part
in the yields. There was not sufficient rainfall during the period of 10
weeks subsequent to planting to moisten all of the dry surface soil.
The result was a dwarfing of the plants and little effect from the ferti-
lizer treatments. The moisture was adequate during the latter half

of the season, and an exceedingly rapid growth resulted. At the
time of maturity the plants were normal in size and the fruiting
good, but the bolls were small.

The cotton yields are given in Table 18. These figures show no
appreciable difference in the availability of the nitrogen in urea,
ammonium chlorid, and ammonium nitrate. At the largest rate of
application the results with all of these newer materials were better
than with ammonium sulphate. The soil irregularities probably were
responsible for this, as shown by differences in yields on the unferti-
lized plats of Section I, ranging from 368 to 1,040 pounds of seed
cotton per acre. The responses to growth produced by all of these
materials indicated that they were equally good. The growth with
urea is shown in Plate XIII, Figure 1.

The yields from the plats of Section II show that this soil was
nearly as variable as on series A, the check plats showing yields of
351 to 840 pounds of seed cotton per acre. In the comparisons be-

—

at

ATMOSPHERIC-NITROGEN FERTILIZERS. 390
>
tween ammonium phosphate and ammoniated superphosphate, using
ammonium sulphate as a standard, there was a slight difference in
favor of ammonium phosphate at both rates of application. At the
smaller rate ammonium phosphate and ammonium sulphate were
of equal value, but with the larger application ammonium sulphate
was considerably better, the actual yields from the adjoining plats
being 1,428 pounds of seed cotton with this material and 1,280
pounds with ammonium phosphate. Cyanamid gave good results

“4 COTTON. CORN:
@ _ SECTION IT SECTION I. _ SECTION ID. SECTION I.

'
y

o26"

Z.

db
MN)
V
3
3
Md

X
3
%

:
(

d»
3315
I] Ol] ¢
3y] 8
alle |ie
eels
STOTT

|
|

S.

ae Oh

Fic. 4.—Diagram of field No. 4, located at Muscle Shoals, Ala., showing plat arrangements and treat-
ments for the season of 1921. The soiltype is Decatur silt loam. Three rows per plat with buffer
row. Size of plats, one-twentieth of anacre. The index figures refer to the number of pounds of
NHs, P20; and K2O used peracre. Ac. P. = acid phosphate; K = potassium sulphate; Cyan. = cyana-
mid; Am. Cl. = ammonium chlorid; Am. S. = ammonium sulphate; Am. N. = ammonium nitrate;
Am. P. = ammonium phosphate; Am. Sup. = ammoniated superphosphate; B. Slag = basic slag.

on this area, the increases over the checks being approximately as
large as with any other material used. The actual yields were con-
siderably lower, however, because the soil at this point was very poor.
At the largest rate of application cyanamid produced injuries and
delayed growth and maturity to such an extent that the yield was
less with 80 pounds of the ammonia equivalent than with 40 pounds.
The a re on the cyanamid plats were a dark green and rather
small but bushy. The bolls were slightly above the average in size
and were nor destroyed to as great an extent by the boll weevil as
were those on adjoining plats.

36 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

Tape 18.— Yields per acre of cotton from Sections I and IT of field No. 4.

Yields of seed cotton (pounds).

sg Ferti-
eatment. ses Plat. Tderoade
Actual. | Average.| over
check.
Section I:

8 1 554
bio fertilizer (0520/4 eu 1) ee Pe eee ae 0- 0-0 : ae \ boi |S oe

Tt ate 2 792
MO WITEROP CNS -eh tata) i oo Se ee ee ee oe 0O- 84 6 664 \ 1287\-. fee
2- 84 3 940 940 212
Ammontim sulphate 225.22 Se eee cae oe eee 4-84 4 990 990 262
8- 84 5 790 790 62

ae ff 448 |)

INO fertilizer 22s acess See ae eee 0- 0-0 12 1, 040 (cee

: 6 664
INDHTUTOBOR 2 usa a nee ses ous ee eee seek 0- 84 ll 1,190 O27 a) eee Se
2- 84 8 920 920 —7
ETON Sete nce at ae ee 4-84 9 1,164 1,164 237
&- 8&4 10 1, 330 1, 330 403
aN DH Pein AI) ee 7 eae eee, ae ee 0O- 0-0 12 1,040 | TOO ia eee

= ie 11 1,190
LYLE 1a CT tipsy meals aepniens Menge pe Ene 5 0- 84 { 16 974 \ LOS 2ie ee. seer
; 2- 84 13 1,510 1,510 428
ATHMOnIUM, Chl Omer Is 2 a. Sons iaaaemene ooheesekiese 4-84 14 1,390 1,390 308
8 84 15 1, 500 1,500 418
Nomertilizer= 223-2 eee kid tee eee eee 0- 0-0 19 368 3682/35 5 sene
WNOUMIDRUR EM ees sfc eect c es oe tat oe ee QO- 84 16 974 Ca ee
: : 4-84 17 1,380 1, 380 406
Ammonium nitrate... .--.2---0s----e0e-2se oes i. 8 84 is| 1470| 12470 496

Section IT:

MW OMIROPENE = — nese es. anche oe ee oe eee 0 5-4 1 840 S40 eee
ENN OWVENESU HALE le =) oo nae el oe eee eee 2-54 2 1,014 1,014 174
Ammoniated superphosphate...................- 2- 54 3 880 880 40
NO MINT ORCA Gets -e Choe a cleign et eens Meee eee eee 0-10-4 5 840 840) |S See
ATMonUM phosphate - .. 135. $6: - he eee oe 2- 7-4 6 1,010 1,010 170
Ammoniated superphosphate..................-- 4-10-4 4 1,110 1,110 270
INODEEMUZED a 5.2 Sone c Sa seat Soe eee see 0- 0-0 10 580 O80) |S.
ENG AIbrOopeNn.s =. of NC Nes. 055-8 oe ee PEE ee ee 0-13-4 9 840 840) SS 5r aes ee
Ammonium phosphate 4-13-4 vf 1, 280 1, 280 440
AmMmoriitim sulphate 22 o2 0322). 2-2 ew eee eee 4-13-4 8 1, 428 1, 428 588
INOWMCRNIZER. octet cs cc Sabre snes REO ee ie 0- 0-0 10 580 O80) [See oan
No nitrogen (acid phosphate)..............:-...-- 0- 84 11 840 840 260
Nomiirogen:(basie'slar) o: Fo. cho erences eee O- 8-4 12 694 694 114
Nowertalisers -srr 3.5 ft io thot): Sakae ease eee 0- 0-0 10 580 §80--|5.c4-.cee =
No nitrogen (with basic slag)........-.++2++++++- o-s4f ig ec | ieee ae ae
2- 84 13 840 840 341
Cyanamid (with basic slag): 23.22. s55.5. 2.26.25 4- 84 14 1,070 1,070 571
& 84 15 984 984 485
Poets AAET spr am eS came e oA nae a ln wminia Seale eee 0- 0-0 19 140 140\\o5 Uae ;
TOSHUEHOP EN: Ses ot = BS Ue Bo oe ke ae 0O- 84 18 351 351 ee ceeee eee
AMIN ONIN MHtTALC. 28. 2s -\o.. ses cecwmnwe cen eee 2- 84 17 823 823 472

Results with corn.—The yields of corn for the two years are given
in Table 19. The results for Section I show good increases with all
the materials. Urea, double salt, ammonium chlorid, and am-
monium nitrate gave about as good results as ammonium sulphate.
The severe weather conditions the second year as well as the natural
soil variations make slight differences insignificant.

es, a ee s

HT |

ATMOSPHERIC-NITROGEN FERTILIZERS,

Ferti-

Treatment. lizer
ratio.

Section I:
No fertilizer....... 0- 00
No nitrogen....... Qe +2
3 - 42
Ammonium sul- 2-42
phate..-..-.---.. 4— 4-2
No fertilizer....... O- 0-0
No nitrogen....... Q- 4-2
1- 42
‘Tole 7 4-2
4-4-2
No fertilizer....... 0- 00
No nitrogen....... O- 4-2
1- 4-2
Double salt }...... 2—- 4-2
4- 4-2
No fertilizer...._- =| oe 00
No nitrogen-....-. # e
Ammonium nitrate 4-4-2
Section I:
No nitrogen....... O- 5-2
Ammonium -

phage 2- 5-2

No nitrogen....... 0Q-10-2
Ammonium phos-
fthe ce 52-5 7-2

No fertilizer....... oe 0-0
No nitrogen......-. 0-13-2
Ammonium phos-
poate =< 3.2 2 4-13-2
Ammonium sul-
ee 4-13-2
No fertilizer....... oe

paosp

No nitrogen (cal-
cined phos
phate)?.......... Q- 4-2

No nitrogen (cal-
cined phos

phate)?.......... 0- 42
Cyanamid (with |f1- 42
calcined phos- = 4-2
phate)?.......... 4- 4-2
No fertilizer....... 0- 0-0
No nitrogen....... Q- 4-2

Ammoniumnitrate| 1- 4-2

1 Ammonium chlorid was substituted for double salt in 1921,
2? Basic slag was substituted for calcined phosphate in 1921.

————

at

_ Tasre 19.— Yields per acre of corn from Sections I and II of field No. 4 in 1920 and 1921.

maa Orie 0 ONO wT

i
SOOO OD

fet
oN OO KF Oa WwW HY fF

il

Yields of corn.

Grain (bushels). Grain (bushels).

i

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38 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

The yields from Section II show no marked differences between
ammonium phosphate, ammoniated superphosphate, and ammonium
sulphate. Cyanamid gave smaller increases than the other nitrogen
carriers, due to the extremely poor and rocky soil. It will benoted
that where ammonium nitrate was used under these conditions it
also failed to give a good growth. We can not, therefore, say that
cyanamid was not as good a source of nitrogen for corn as the other
materials used. The early growth of corn with ammonium sulphate
and ammonium phosphate is shown in Plate XIII, Figure 2, and
the yields with ammonium nitrate and ammoniated superphosphate
in Plate XIV, Figures 1 and 2.

Fretp No. 5.

Another area of approximately 5 acres was used for experimental
purposes in 1920. The treatments and general plat arrangements
were an exact duplicate of field No. 3. Unfortunately, the soil was
so fertile that the fertilizers produced negligible increases in most
eases. For this reason work was not continued on this area during
1921.

The yields mean very little except on those plats receiving am-
monium chlorid and cyanamid and planted to corn. It happened
that the soil on this portion of the field was rather poor and quite
ey These figures are given in Table 20, but all others are
omitted.

TABLE 20.— Yields per acre of corn from Sections I and II of field No. 5.

Yields of corn.

Grain (bushels).

Fertilizer ratio. Plat.
Stalks
(pounds). Increase
Actual. | Average. over
check.
Section I.— Ammonium chlorid: 5m aie
1 5

0-0-0... 220-22 e eee eee eee cece eee eee eee eee sce re rs { 12| 1,780 25. 4 \ 24.9 |o..----2ee

6 2, 200 24.0
OAD... enone eben ee eee en eens ne nen ece een eneics { 11| 2240 33.1 \ 28.6 |-.-+----.
ae en actos tere a otis ce teeth tere ama ee eee 8 2, 800 32.6 32.6 4.0
coe ola ae eS TO 9 2, 960 42.9 42.9 14.3
HAE ara § Se EE Be SE ER Mo IS = 10 2, 580 41.1 41.1 12.5

Section II.—Cyanamid:

Ae Ee eee GAs Bd eicin clotn dic winwes See 10 1, 440 14.8 14.3) scc0aceeee
eae aplten pea Micaco se Pay oa Acs gr a gS 12 1, 688 16. 1 16.1 Losoecee
jE Ae Po a Get a OES aoe See ae eee ios 13 2,273 16.7 16.7 6
Ae eee Sh See te a oe wie cine ne ea cee ema cots ate 14 , 790 28.6 28. 6 12.5
7s OI A ee AOE eS Sa ec 15 3, 083 33.1 33.1 17.0

The increases in yields produced by ammonium chlorid were very
good, but the material again shows indications of being slightly
toxic when applied in high concentrations. Soon after germina-
tion the plants showed a distinct burning and some yellowing of
the leaves with the application of 40 pounds of ammonia per acre.’
A few plants died, but the others apparently recovered. The yields
indicate that the bad effects were never completely overcome. _

Cyanamid gave excellent results on corn and showed a much higher
yield with 40 pounds of the ammonia equivalent than with 20 pounds.

ATMOSPHERIC-NITROGEN FERTILIZERS. 39

_ At the smallest rate most of the nitrogen was utilized for stalk produc-
tion rather than grain. The probable causes for this are the same as
reviously stated in connection with other plats. Under the con-
| ee of this test cyanamid produced just as satisfactory early
- effects and also gave as good increases in yields as could be expected
_ from any fertilizer.
| REVIEW OF THE RESULTS.

An examination of the results here reported shows that with the
exception of cyanamid all of the nitrogen materials tested gave
responses quite similar to those from ammonium sulphate and
sodium nitrate. It should be pointed out, however, that some of
the materials, especially Urephos, were not tested on a sufficiently
large number of plats to show clearly their relative values, but never-
theless, under the conditions of the test cyanamid was the only
fertilizer which in some instances gave very erratic results. Because
of the erratic results obtained with cyanamid and the unusual in-
terest attached to this material as one of the important synthetic
sources of nitrogen, special consideration of it seems desirable. In the
following discussion the various phases of cyanamid fertilization will .
be considered, both from the standpoint of the present study and in
the light of results reported by other investigators.

The importance of avoiding the use of cyanamid in large propor-
tions in fertilizer mixtures containing acid materials has been em-
phasized. Where large amounts of cyanamid were mixed with acid
ee the growth and yields of the various crops were poor.

his was due to the polymerization of a portion of the cyanamid nitro-
gen to dicyanodiamid, which is not only unavailable as a fertilizer
but also toxic for some plants. When cyanamid and acid phosphate
were applied separately the undesirable changes were avoided; like-
wise in the case of mixtures containing basic phosphates. It is
customary in American fertilizer practice to use not to exceed 60

ounds of cyanamid per 1,000 pounds of acid phosphate in mixed
ertilizers. While under such conditions a small amount of dicyano-
diamid may be formed, the quantity is not sufficient to be par-
ticularly objectionable and the mechanical condition of the mixture
is considerably improved.

The method of using cyanamid in the field is very important. In
the experimental work at Muscle Shoals the conditions of use adopted
were made to conform as nearly as possible to American agricultural
practice. This fact needs to be especially emphasized, since in many
cases it largely explains the poor results with cyanamid. The main
factors, namely, soils, crops, and time and methods of application
deserve special mention.

The soils which are usually considered most suitable for cyanamid
fertilization are those in best tilth, neutral, and having high nitrifying
efficiencies. ‘Those which are not suitable are acid soils, very sandy °
soils, acid humus soils, and very heavy plastic clays. A good supply
of colloids and organic matter is also considered desirable; likewise a
high absorptive capacity provided the aeration is adequate. The
soils used for the experiments here reported were loams and therefore
apparently satisfactory. However, all of the soil types were slightly

_ acid and some of them poorly aerated, especially on fields 2 and 3.
_ The nitrifying powers were likewise low, as shown by laboratory

€ ~~

40 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

experiments with soils from fields 1, 2, 3, and 4. In every case the .

sous nitrified ammonium sulphate satisfactorily, but the nitrates — |

present in the soils two months after receiving cyanamid were fre-
quently less than in untreated portions. A general average of the
numerous determinations made showed that the soil of field 1 nitri-
fied best, that from field 4 came second, while fields 2 and 3 were the
poorest. This agrees almost exactly with the relative increases in
cotton yields obtained from these various fields. The fact that all
sous readily nitrified ammonium sulphate but not cyanamid indicates
rather definitely that the dicyanodiamid formation in the poorly
aerated and sometimes poorly drained soils of fields 2 and 3 was
primarily responsible for the lack of nitrification and poor cotton
yields with cyanamid. Very small amounts of this material are
sufficient to prevent nitrification entirely.

The crops which usually give the best results with cyanamid,
judging from results reported in the literature and those here obtained,
are the ones that have a long growing period and can utilize ammonia
nitrogen. Crops that require nitrate nitrogen frequently make very
poor growth, because cyanamid nitrifies so slowly. This fact is
thought to explain the results here reported, where cotton frequently
gave poor responses to cyanamid nitrogen, while corn always grew
rapidly and produced as good yields as with standard fertilizers.
Since the transformation of cyanamid nitrogen to nitrate nitrogen
is usually a slow process, cyanamid should never be used as a fertilizer
for quick-growing crops, such as vegetables, unless the material is
applied several days or weeks before seeding. Even then a nitrate
fertilizer would probably prove more profitable. The use of nitrate
nitrogen in combination with cyanamid is advisable provided such a
mixture is a compatible one, as was not the case in the tests reported
in this bulletin.

The time and method of application are of very great importance in
cyanamid fertilization. In order that sufficient time will be avail-
able for nitrification, the material should be applied at least 10 days
before seeding, or in the case of most perennial crops an early spring
application before growth begins is best. In these experiments the
cyanamid was usually applied at the time of seeding in order to
conform to the prevailing American practice. A retarded early
growth and a delayed maturity were the natural results. Applica-
tions to growing crops usually depress growth for a month following.
This occurred in the time-of-application studies reported on previous
pages, particularly with cotton. Since coru can utilize ammonia
it is less susceptible to what is ordinarily considered as bad practice
in the use of cyanamid. With regard to the method of application,
it seems that a more intimate mixing of the cyanamid with the soil
than can be obtained by distribution in the row is desirable.

The explanation for the peculiar behavior of cyanamid under
some of the conditions outlined depends upon the chemical changes
which take place. From the studies which have been reported on
this subject and from those made in connection with the present
investigation, it appears that almost immediately upon coming into
contact with moist soil cyanamid changes into calcium-acid cyanamid,
then free cyanamid (H, CN,), urea, and eventually ammonia.
varying quantity of dicyanodiamid may be produced as a side reac-
tion. The free cyanamid and dicyanodiamid are toxic to the nitrify-

ATMOSPHERIC-NITROGEN FERTILIZERS. Ads

ing bacteria, and the ammonia can not be oxidized to nitrates until
the injurious compounds are so dispersed, changed, or absorbed as to
be no longer present in sufficient concentration to be injurious.
Until this does occur the plants are forced to take up ammonia or
_ undergo nitrogen starvation. The unusually green color of many
plants fertilized with cyanamid is probably in some way connected
with ammonia absorption.

The explanation of why the retardation period following the use
of cyanamid lasts for only a few days in one case and throughout
the summer in another probably depends upon the particular com-
pound primarily responsible for the effect. If it is merely ammonia
or free cyanamid, these materials will be quickly changed or dis-

_ persed and nitrate production may proceed normally. If dicyanodi-
amid, the effect may be expected to continue for a considerable
period, since the compound is not only relatively insoluble but not
readily attacked by chemical or biological agents.

SUMMARY.

This bulletin presents the results of field tests with 10 atmospheric-
nitrogen products conducted during a period of three years on an
area of about 10 acres the first year and 20 acres the last two years.

Cyanamid usually was not as satisfactory as the other sources of
nitrogen, chiefly because so many factors influence the rate and
manner in which the material is decomposed either in fertilizer
mixtures or in the soil. When mixed with acid phosphate in large
proportions the results were poor, probably owing to the transfor-
mation of a portion of the cyanamid nitrogen to dicyanodiamid,
a compound which is not only unavailable but toxic for some crops
and for the nitrifying bacteria. Where applied separately with
acid phosphate the results were good even with 1,000 pounds of
an 8-8-4 fertilizer. Calcined phosphate and basic slag appear to
be entirely satisfactory as to compatibility as sources of phosphorus
for use with cyanamid.

The behavior of cyanamid in the soil depends upon a number of
factors, such as time and method of application and the type, com-
position, temperature, and moisture content of the soil. Applica-
tions should be made at the time of seeding, or preferably earlier.
It is, furthermore, believed that thorough mixing of the cyanamid
with the soil is preferable to drilling in the row. Even under the
best conditions cyanamid nitrogen is converted to nitrates rather
slowly and for this reason is usually slow to act. The soil condi-
tions which are known to hasten nitrification are, in general, the
ones which favor an efficient utilization of cyanamid.

The marked differences in the response of different crops to cyana-
mid under the same conditions has been very clearly brought out
by the experiments with corn and cotton. Corn gave as good
yields in most instances with cyanamid as with any other fertilizer
used. Only a very temporary period of retardation was in evidence
during early growth. Cotton was usually retarded for a consider-
able period subsequent to germination and in most cases never
produced as good growth or as large yields with cyanamid as with
ammonium sulphate or sodium nitrate. This is believed to have been
due to the fact that cotton requires nitrate nitrogen for its best

,.
os

42 BULLETIN 1180, U. S. DEPARTMENT OF AGRICULTURE.

growth, while corn can efficiently utilize ammonia. Further experi-
mentation with cyanamid as a possible corn fertilizer seems’ espe-
cially desirable.

Where used on winter grains with half of the nitrogen supplied
in the fall and the remainder in the spring, cyanamid gave about
as good increases on the average as the two standard materials.
Where all the nitrogen was applied in the fall to wheat and rye, the
results were even better. This emphasizes the desirability of allow-
ing a considerable period of time for cyanamid to become available
in order that it may produce the maximum yields.

The comparisons between acid phosphate, calcined phosphate,
and basic slag made in connection with the use of cyanamid showed
only slight differences in yields, but the experiments were on too
limited an area and for a period too short to justify a definite state-
ment as to their relative values.

The attempts to utilize cyanamid more effectively by the addition
of egalcium nitrate to mixtures containing it were not entirely suc-
cessful. This was attributed to the fact that where calcium nitrate
is used with basic slag the mixture becomes moist during damp
weather and on drying produces very hard cakes. At the same time

the moisture probably favors the production of dicyanodiamid from ~

the cyanamid present. If a compatible nitrate-cyanamid mixture
could be developed, such a combination would undoubtedly be more
desirable than cyanamid alone. In such a mixture the nitrate
nitrogen would supply the needs of the plants while the cyanamid
nitrogen was being made available.

Ammonium nitrate gave results comparable with sodium nitrate
and ammonium sulphate. It was readily available and no abnormal
effects were noted. The chief limitation to its use is its property of
absorbing moisture from the air, making it somewhat unsuitable for
fertilizer mixtures. This objectionable feature can be partially over-
‘ come by either graining and oil coating the material or by manu-
facturing double or mixed salts from it.

Double salt, made from ammonium nitrate and ammonium sul-
phate, produced effects comparable with either of the materials used
singly. The material is somewhat hygroscopic, but not nearly to the
same extent as ammonium nitrate.

The two mixed salts, made from ammonium nitrate and either
potassium chlorid or potassium sulphate, were of approximately
equal value. So far as may be judged from the limited use of these
materials, they are as available as either ammonium nitrate or
ammonium sulphate. Although somewhat hygroscopic they are less
objectionable in this respect than ammonium nitrate.

Ammonium phosphate and ammoniated superphosphate are ex-
cellent nitrogen carriers. They gave quick responses, good growth,
and satisfactory yields. The large quantities of phosphorus in the
materials partially masked the nitrogen effects.

Ammonium chlorid was as readily available as ammonium sul-
phate, but on a few plats 40 and 80 pounds of ammonia per acre
showed some toxic effects and gave slightly lower yields than the
equivalent amount of nitrogen as ammonium sulphate. This may
have been due to too high a concentration of the chlorid ion, but no
work was done to determine this point.

ATMOSPHERIC-NITROGEN FERTILIZERS. 43

Urea seemed to be as readily available as sodium nitrate and
equally as good in all respects as any other material used. Since
urea is an excellent material physically and leaves neither a basic nor
acid residue in the soil it should prove to be an almost ideal nitrogen
carrier for all types of soils.

Urephos gave somewhat variable results, due to the wide soil
variations, the yields being especially good with wheat but much
poorer with rye. The limited use of the material does not justify
conclusions as to its value.

It should be noted that nearly all the fertilizer materials tested
have a much higher plant-food content than those now commonly
employed. ile some of these materials are suitable for direct use
in mixed fertilizers, others will require some modifications of present-
day fertilizer practice, owing to their physical condition.

The results as a whole may be summed up by the statement that
under the conditions of these experiments all of the nitrogen mate-
rials tested with the exception of cyanamid were of about the same
value as sodium nitrate and ammonium sulphate. With regard to
the latter two materials, if there was any difference between them it
was slightly in favor of ammonium sulphate.’ Further experimenta-
tion is necessary, however, to stat lish more definitely the relative
values of all of these materials and to determine the conditions under
which they can be most advantageously used. Such experimenta-
tion is now in progress by the Office of Soil-Fertility Investigations.
It is hoped, however, that similar studies will be undertaken by
others, since atmospheric-nitrogen products are becoming increas-
ingly important in supplying the needs of agriculture.

: ORGANIZATION OF THE
UNITED STATES DEPARTMENT OF AGRICULTURE.

October 15, 1923.

secretary of Agriculture. 23:27 05. 612. el Henry ©. WALLACE.

Assistant Secretary.......- oh, SSE LY Say ent tle ee Howarp M. Gore.

airector oy ascienciec Work: £222 ek E. D. Bat.

Director of Regulatory Work................-- WALTER G. CAMPBELL.
Director of Extension Work................... C. W. WARBURTON.

Mreather Prireaiy OD. ir ME OES CHARLES F. Marvin, Chief.
Bureau of Agricultural Economics........-.-.- Henry C. Taytor, Chief.
Bureau of Animal Industry... ...........-.-- JoHN R. Mouter, Chief.
Wenseai Of -PUtil Rar ye Ske ee eet 2 Wiu1aM A. Taytor, Chief.

EOC TNE Sa) ciao linac alee gee eae ed 2 W. B. GREELEY, Chief.

Bureau of Chemistry.....---- pate eer ege phe epee C. A. Browne, Chief.

DERE OO 0) Bagi ape ely Sah Bel oo mA BA Mitton WHITNEY, Chief.
Bircaw Of Latomovgy...<.2-- 5 2. See L. O. Howarp. Chief.

Bureau of Biological Survey.....---.-.-.-.-2+- KE. W. Netson, Chief.

irene Of ube Roads... 22.2220 teen Tomas H. MacDonatp, Chief.
Bureau of Home Economics......-.---------- LOUISE STANLEY, Chief.

Fixed Nitrogen Research Laboratory. ath eee F. G. Cottre.., Director.
Division of Accounts and Disbursements.......- A. ZAPppone, Chief.

TE Eg IE aS eg a SA cd a ot am ete fa CLARIBEL R. Barnett, Librarian.
Federal Horticultural Board...............---. C. L. Maruatt, Chairman.
Insecticide and Fungicide Board.............. J. K. Haywoop, Chairman.
Packers and Stockyards Administration.......-. he MorriLu, Assistant to the:
Grain Future Trading Act Administration. . ... Secretary.

Pence of the Solicitor... . 22.2522: 0.555. see R. W. Wiuu1ams, Solicitor.

This bulletin is a contribution from

Rureauof Plant Industry.) .J20. 52224. Lee - - WruramM A. Taytor, Chief.
Tobacco and Plant Nutrition Investigations W. W. GARNER, in Charge.
Fixed Nitrogen Research Laboratory.......---- F. G. Cottrett, Director.
Chemical Division’. 0.2... 220s ean JosrpH M. Branam, in Charge.
44 &-

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