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3 Agriculture Handbook No. 1981 l\^^^^

U.S. DEPARTMENT OF AGRICULTURE Q^T 2 3 \

Agricultural Research Service I CORBE«^^^

For Direct

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LIQUID

NITROGEN

FERTILIZERS

Agriculture Handbook No. 198

Washington, D.C.

UNITED STATES DEPARTMENT OF AGRICULTURE

Issued September 1961

Agricultural Research Service
Contents

Page

EARLY DEVELOPMENTS

COMSUMPTION OF LIQUID NITROGEN

MATERIALS

CHARACTERISTICS OF LIQUID NITROGEN

MATERIALS

Compositions

Chemical properties

Pliysical properties.

Physiological properties

MANUFACTURING PROCESSES AND FACILITIES

SAFETY REGULATIONS AND PRECAUTIONS

MARKETING AND DISTRIBUTION

STORAGE AND TRANSPORTATION

Storage .

Transportation

Transfer

APPLICATION METHODS AND EQUIPMENT

Subsurface application

Surface application

Nitrogen losses during application

6

6

8

9

11

12

14

15

16

16

18

18

19

19

22

23

Page

LIQUID NITROGEN FERTILIZERS IN THE

SOIL 24

Nitrogen Sorption 24

Effect on soil properties and population 25

Nitrogen losses after application 27

TIME OF APPLICATION 29

Application on small grains 30

Application to crops for grazing 31

SELECTION OF LIQUID NITROGEN FERTILIZER 31

CROP RESPONSE 32

Corn 32

Cotton 32

Hay and pasture 33

Rice 34

Oats and barley 34

Wheat 35

Sugarcane 35

ECONOMIC CONSIDERATIONS 36

LITERATURE CITED 37

APPENDIX 44

Washington, D.C. Issued September 1961

For sale by the Superintendent ol Documents, U.S. Government Printing Office Washington 25, D.C. - Price 30 cents
LIQUID NITROGEN FERTILIZERS

For Direct Application

By J. RICHARD ADAMS, senior chemist, and M. S. ANDERSON,' principal soil scientist, Soil

and Water Conservation Research Division, and W. C. HULBUET, principal agricultural

engineer, Agricultural Engineering Research Division, Agricultural Research Service "

Nitrogen fertilizers are applied as individual

materials and us mixtures witli carriers of one or

more of the other primary plant-nutriei^t elements

(phosphorus and potassium). The proportion of

the total domestic consumption of fertilizer nitrogen used as separate materials was about 43 percent in 1900, 59 percent in 1920, and 63 percent in

the year ended June 30,1958.

The direct application of liquid materials as

fertilizer carrying nitrogen as the only primary

nutrient element has greatly increased in the

United States since World War II. Such use of

these liquids—comprising mostly anhydrous ammonia, aqua ammonia, and aqueous solutions of

ammonium nitrate and (or) urea with or without

ammonia—accounted for about 46 percent of the

consumption of nitrogen in direct-application materials in the year ended June 30,1958, as compared

with only 8 percent in 1946-47. Liquids are also

the principal form in which nitrogen is supplied

to domestic manufacturers of mixed fertilizers.

About 60 percent of the nitrogen in such fertilizers

was derived from liquids in 1954 (14-) .^

Although not discussed in this publication,

additional tonnages of other liquid fertilizers—

phosphoric acid and aqueous solutions of polymitrient materials and mixtures—are used annually as direct-application materials. Scholl and

coworkers (J68) reported consumption of 23,067

tons of phosphoric acid in 1957-58, an increase

of 51 percent over the quantity consumed in 1953-

54 (104).

Liquid nitrogen fertilizers have certain advantages o\'er conventional solid fertilizers. Many

of the licpiids have a higher nitrogen content and

cost less per pound of nitrogen. They can be

applied accTirately to the soil without dusting and

are more adaptable to incorporation in the water

of irrigation systems. Ease of handling is a

major consideration. Liquid fertilizers are handled mechanically so that the lifting and carrying

of hea\y bags of fertilizer are eliminated. Liquid

nitrogen fertilizers, however, are corrosi\-e and

require special application equipment and storage

containers. Many of them must be handled in

pressure equipment. A drop in temperature may

cause salting out of some of the dissolved solids

and subsequent clogging of equipment.

The purpose of this publication is to bring together information on the consumption, composition, and properties of liquid nitrogen materials;

the processes and facilities for their manufacture;

the methods, equipment, and safety precautions

for their storage, transportation, and application;

and the agronomic and economic considerations

in their use.

EARLY DEVELOPMENTS

More than a century ago Liebig suggested the

possibility of using the ammoniacal liquors from

coal gas plants as a source of fertilizer nitrogen.

In 1843 Bishop (4.3) compared the effects of ammoniacal water, potassium nitrate, sodium nitrate,

and rape-dust on grassland in Scotland. The ammoniacal water scorched some of the grass and

was a little slower than sodium nitrate in stimulating gi-owth, but it pi'oduced a 25-percent

greater grass yield than the other sources of

nitrogen.

' Retired November 30, 19.57.

^ The authors gratefully acknowledge the valuable suggestions and assistance of K. D. .Jacob in the preparation

of the manuscript, and the assistance of C. W. Gantt. .Jr.,

reseach agricultural engineer, in compiling information

of application equipment.

' Italic numbers in parentheses refer to Literature

Cited, p. 37.

Lawrence (J14-) refers to a pamphlet printed

in 1848 that cited many examples of fanners using

ammonia liquor for fertilizing grassland. In

1852 Johnston (106, p. 2J^8) wrote "To grassland

this ammoniacal liquor may be applied with great

advantage, by means of a water-cart—being previously diluted -with from three to five times its

bulk of -water. If too strong it will burn up the

grass at first, especially if the Aveather be dry;

but, on the return of rain, the herbage will again

spring up with increased luxuriance. On arable

land it may be applied with profit to the young

wheat or other corn by the water-cart . . ."' In

1891 Shutt {173), of "the Canada Experimental

Farms, reported that some people Iiad applied

ammonia liquor, diluted with three times its bulk

of water, directly to the soil with safety and profit.

He emphasized it could be used with safety only
AGRICULTURE HANDBOOK 198, U.S. DEPARTMENT OF AGRICULTURE

after careful experiments and previous dilution.

According to McMillan {130), Mach found at the

Agricultural Institute, Baden, early in the 20th

century, that ammonia water \Yas an effective

source of fertilizer nitrogen which should be applied and plowed under about 2 weeks before

seeding.

Marsden {136) and Lawrence {llJf) discuss the

development of the use of gas (ammoniacal)

liquor as a fertilizer in England. An attempt

during the latter part of World War I to interest

farmer's in the use of gas liquor met with no success. The Shepton Mallet Gas Co. made a number

of experiments with the liquor in 1931, and its

experimental use as a source of nitrogen for market gardens was sponsored by the Tottenham Gas

Co. in 1936. It was found satisfactory for cabbage, potatoes, beetroot, turnips, carrots, and

asparagus. Successful tests were made later on

grass, kale, and cereal crops. Beginning in 1950,

a number of the gas companies or boards applied

large quantities of gas liquor to the soil. One

group applied 7 million gallons from 1950 to 1955

and a second group applied 5% million gallons

in 1954. In 1952 the British Government recognized gas liquor as a nitrogenous fertilizer and

granted a subsidy for its use.

The fertilizing value of ammonia liquor has also

been demonstrated in a number of other foreign

countries. Among these are Czechoslovakia (113),

Italy (74), Germany (^i, 5£, 156), Japan {101),

Poland {65), and U.S.S.R. {110).

Experiments were initiated in 1949 in France

and Algeria on the use of anhydrous ammonia as

a fertilizer material. Gros {92) reported that in

France anhydrous ammonia, placed about 6 inches

below the surface of the soil, produced about 3 percent more sugar beets per acre and gave larger

yields of bigger and better appearing tubers than

mineral fertilizers. Rebour {158) found that the

addition of anhydrous ammonia to irrigation

water in Algeria adversely aiïected the permeability of the soil and caused some loss of humus.

According to Hunter and Jarvis {99), the first

record of the fertilizer use of ammonia gas in

Britain was in 1953. They showed that ammonia

injected 4 inches into the soil was as effective as

ammonium sulfate in promoting the growth of

kale. They also showed that the growth of pasturage was promoted by ammonia gas but that

response might be slower than with ammonium

sulfate. Mulder {144) found the delayed response

to anhydrous ammonia to be objectionable under

the growing conditions encountered in the Netherlands.

As reported in 1931, the early work in this

country on the use of aqua ammonia as a source

<^f fertilizer nitrogen was carried out by Tiedjens

and Bobbins {187) with sand cultures in New

Jersey. Aqua ammonia was found to be an ideal

source of nitrogen under many conditions and a

better source than either ammonium sulfate or

calcium nitrate for tomatoes and soybeans. Experiments by Beaumont and Larsinos {35) in

Massachusetts showed that surface applications

of aqua ammonia did not impair germination or

stand of a number of crops but did burn the foliage

of established grass sod. The injury was confined

to the portion of the plant above ground and was

temporary. Aqua ammonia proved only about

70 percent as effective a source of nitrogen as

ammonium sulfate or sodium nitrate. Pot tests reported by Chapman {58) in 1936 showed that

ammonium hydroxide applications gave significant increases in the growth of sudangrass on two

calcareous soils in California and was slightly toxic

on a third. In 1943 Andrews and others {27) ap1^1 ied aqua ammonia to field crops, but no response

data were given. The following year Maclntire

{1£8) and coworkers found that surface applications of aqua ammonia at rates up to 50 pounds of

nitrogen per acre were comparable to equivalent

quantities of ammonium nitrate and ammonium

sulfate in promoting the growth of sudangrass on

two typical acid Tennessee soils.

Experimental work was started in 1931 {1) on

the application of anhydrous ammonia to the soil

in irrigation water. The first commercial application was made the next year on California citrus

{171). No ammonia toxicity was observed by

AVaynick {WO) either on citrus trees or on a wide

variety of field crops after 3 years of experiments

with anhydrous ammonia applied in irrigation

water. Rosenstein {161) found in 1936 that irrigation water containing ammonia was a satisfactory source of nitrogen for more than 20 California

crops. This method of applying anhydrous ammonia to the soil was given the trade name "Nitrogation" in the farWest {116,117,118).

Andrews and others {27) stated that J. 0.

Smith injected anhydrous ammonia directly into

the soil in Mississippi in 1930 but gave no indication as to the results he obtained. Study of soil

injection of anhydrous ammonia was begun in

California shortly after application of this fertilizer in irrigation water had gained acceptance.

Injection proved feasible {116, 117,118), and the

first commercial application was made in California {171) in 1939. A patent {115), covering the

method of application, was granted in 1942 and the

term "Nitrojection" was applied to the method

on the west coast {116,117,118). Direct application of anhydrous ammonia was limited until supplies became pleantiful after World War II.

Publication in 1947 of the findings of Andrews

{22) and Andrews, Edwards, and Hammons {25,

26) in Mississippi, coupled with shortage of solid

forms of nitrogen, created a market for anhydrous

ammonia fertilizer. The development led to further research in Mississippi {23,24,27).

Lijnited quantities of ammoniacal solutions of

ammonium nitrate and (or) urea have been used

for direct application to the soil. In 1947 Hanway,
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION

Luebs, and Rhoades {96) applied an ammoniaammonium nitrate-water solution below the surface of the soil in a winter wheat experiment in

Nebraska. The present writers have personal

knowledge that a similar type of solution was

shipped at about the same time into both Arizona

and California for application in irrigation water.

Such solutions are applied commercially in irrigation water or injected beneath the surface of the

soil with specially designed equipment.

The possibility of using aqueous solutions of

nitrogen materials as fertilizer has long been recognized. In 1845 Boussingault (.^7, /;. 256) stated

that Davy had found that an aqueous solution of has never developed.

ammonium carbonate favored the growth of

wheat. Research since then has shown that nitrogen fertilizer materials applied in aqueous solutions or as solids are equally effective in promoting crop growth. The development of aqueous

solutions reduced material processing time and

supplied some of the unsatisfied demand for fertilizer nitrogen.

Aldrich and coworkers [16) reported in 1953

that field experiments showed nitric acid and nitrogen dioxide compared favorably with conventional

fertilizer nitrogen materials as sources of nitrogen.

However, the use of these materials as fertilizer

CONSUMPTION OF LIQUID NITROGEN MATERIALS

Solids were the only commercial source of direct

application nitrogen until in the 1930's when liquid sources were first used. Little information is

available on the consumption of liquid sources of

fertilizer nitrogen previous to 1946^7.

Separate materials applied directly to the soil

accounted for over 40 percent (table 1) of the

783,588 tons of nitrogen consumed in 1946-47,

with less than 8 percent of the direct application

nitrogen in liquid form. Liquid products supplied

almost 20 percent of the nitrogen in separate materials in 1951-52 and more than 45 percent in

1957-58.

TABLE 1.—Consumption of fertilizer nitrogen in short tons

and the portions used for direct application in single

nutrient liquids and in all separate materials, years

ended June 30, Id^lSS ^

Total consumption 2

Portion consumed in1 ear ended June 30—

Single

nutrient

liquids

All separate materials

1947.... .

Tons N

783, 588

856, 719

919, 946

1,005,524

1, 236, 977

1, 422,160

1, 637, 056

1,847,416

1,960,536

1,933,342

2,135, 287

2,284, 359

Percent

3.2

4.8

6.3

7.7

8.7

10.7

12.2

18.3

19.1

22.8

24.5

28.6

Percent

40.3

1948.... 42.4

1949. 44 3

1950... 50.7

1951 52.8

1952. 54.4

1953 56.5

1964 57.9

1955.. 69.0

1956 58.8

1967.... 60.5

1968.. 62.6

' United States and Territories.

'Data lor 1947-54, from Mehring, Adams, and Jacob (1S9, p. IS); tor 1955-

58, from Scholl and others (165, 166, 167, 168).

Table 2 shows that the consumption of nitrogen

ill the liquid nitrogen products used for direct

application increased from 1,230 tons in 1934 to

652,348 tons in 1957-58. The increase has been

continuous since 1942, with the greatest increases

occurring in recent years. The consumption in

1957-58 was more than six times that in 1950-51 ;

about one-fourth of the increase took place in

1953-54.

Anhydrous ammonia was the only liquid nitrogen product used commercially for direct application until 1946, when aqua ammonia and other

nitrogen solutions came into commercial use. Nitrogen in the form of anhydrous ammonia accounted for more than 85 percent of the directapplication nitrogen applied annually in liquid

form until 1952-53. The relative proportion of

nitrogen in this form started to decline in 1952-53

and was only 71 percent in 1956-57. In spite of

the percentage decreases, the consumption of nitrogen supplied by anhydrous ammonia has increased annually since 1942.

Nitrogen solutions accounted for 27 percent of

the nitrogen applied to the soil in liquid form in

1957-58. Aqua ammonia supplied annually less

than 50 percent of the nitrogen applied to the

soil in nitrogen solutions until 1954-55. The aqua

TABLE 2.—Consumption in short tons, as separate materials, of liquid nitrogen fertilizer products, calendar

years 19SJf-46, and years ended June 30, 1947-58 ^

Anhydrous

ammonia '

Nitrogen solutions '

Year

Aqua

ammonia

other

solutions

Total

Calendar year:

1934

Tons N

1,230

2,050

3,280

3,280

3,280

3,280

4,100

5,740

1,230

5,740

10, 660

14,350

16,400

22, 397

35. 556

53, 789

70,123

97,107

137, 983

178,074

287,155

290,337

344,317

371,668

479,109

Tons N

0

0

0

0

0

0

0

0

0

0

0

0

19

78

1,095

1,275

2,340

4,158

4,252

6,387

22, 600

46,617

62, 510

76,844

73, 342

Tons N

0

0

0

0

0

0

0

0

0

0

0

0

804

2,815

4,688

2,972

5,157

6,351

10, 027

14, 933

28,804

38, 362

34, 493

75, 241

99, 897

Tons N

1,230

1935 2,050

1936 3,280

1937 3,280

1938 3,280

1939 3,280

1940

1941

1942

1943

1944

1946

1946

4,100

5,740

1,230

5,740

10,660

14,350

17,223

Year ended June 30—

1947 25,290

1948 ... -- 41,339

1949 58, 036

1950 77,620

1951 107, 616

1952 152, 262

1953 199,394

1954 . .

338, 559

1955 375,316

1956 . . ...

441,320

1957

1958

523, 753

652,348

1 United States and Territories.

-1934-16, 82 percent of estimated ammonia consumed as separate material

reported hy Mehrlrif;, -\daras, and Jacob (159. ¿2); 1947-55, Adams

and Scholl (I.S); 1956-58, Scholl and others (;ö'V, .- , 168).

3 1946-54, unpublished data from U.S. P ¡m-tment of Agriculture fertilizer consumption surveys; 1965-58, Scholl and others (16S ,18", 187, 168).
AGRICULTURE HANDBOOK 19 8, U.S. DEPARTMENT OF AGRICULTURE

ammonia was the source of 55 and 64 percent in

1954-55 and 1955-56, respectively, but only 50 percent in 1956-57. Only 42 percent of the nitrogen

in nitrogen solutions was in the form of aqua ammonia in 1957-58.

Data for nitrogen applied directly to the soil

in the form of anhydi'ous ammonia are given by

States and regions in table 3. The greatest tonnages have been used armually in the East South

Central, West North Central, West South Central,

and Pacific States. Use of anhydrous ammonia in

the States along the Atlantic Coast and in the

mountain area has not developed as rapidly as in

the other regions. Anhydrous ammonia was used

TABLES.—Nitrogen, Í7i short tons, applied to the soil as anhydrous ammonia, hy States and Territories, years ended

June 30, 19Jp-58 ^

State and region 1947 1948 1949 1950 1951 1952 1953 1954 1955 1966 1957 1958

ConnecticutTons N' Tons N Tons N Tom N Tons N Tons N Tons N

5

Tons N

2

Tons N

11

Tons N

2

Tons N

0

Tons N

0

New England 5 2 11 2 0 0

1

448

293

174

140

170

263

142

179

371

3

21

319

505

196

524

69

198

214

474

159

333

0

459

421

480

25

339

0

696

New Jersey 21 120 297

572

Delaware 22

167

41

7 434

0

Middle AUantic-- 28 315 1,056 1.128 1, 633 1,378 1,724 2,040

Vircinia 113 43

360

383

1, 159

117

4,005

0

270

2,930

408

4,872

572

668

6,092

453

5,649

371

689

6,299

678

6,225

892

910

6,934

1,753

6,899

1,418

605

6,482

South Carolina 1,395

1,002 1,360 2,196

151

9,666

Florida 2, 622

1,002 1,473 2,750 5,664 9,052 13,133 13, 783 17,914 20, 669

Ohio 895

521

3,973

12

1,789

1,358

16,408

519

558

2,388

7,0'JO

23, 682

1,178

1,597

2,479

8,734

14,216

1, 305

2,311

1,840

9,033

15, 246

1,451

2,747

2,352

8,230

12,091

2,963

2, 723

3,270

Indiana 20

43

168

1,065

8

15, 234

20,842

3.369

4,206

East North Central 63 1,241 5,401 20, 632 35, 835 29, 044 30,317 28, 359 46, 921

699

4,097

10, 311

19

213

7,631

3,564

4, 823

17, 252

IS, 219

25

1,113

20, 741

7,419

12, 704

14, 681

12, 297

110

1,391

18, 691

6,997

11,243

8, 639

12, 757

84

1,328

29,682

6,765

10, 265

12,322

12,611

193

637

37, 362

6,285

16,069

Iowa 43

1,662

0

2,832

505

7,306

14, 872

17,658

North Dakota 456

South Dakota 1,128

1,071

21

1,495

676

66, 266

41 7,751

1,746 3,924 9, 982 26, 434 69, 692 66, 871 70, 498 79, 575 114,200

Kentucky _ __ 139

2,800

618

24,487

293

1,478

1,138

21,517

674

3, 211

2,427

22, 737

517

2,802

1,670

22, 198

1,080

5,386

2,137

37, 215

653

3, 754

1,888

33, 506

1,347

9, 877

2,411

37,001

1,803

7,332

2,871

35,161

2,576

43 1,037

192

22, 495

4,466

Alabama 3,466

Mississippi 1,847 10, 565 32,046

East Soutli Central 1,847 10, 598 23,724 28, 044 24, 426 29,049 27,187 45, 818 39, 801 60, 636 47,167 42, 554

Arkansas 1,130

1,458

3,524

5,415

21

140

.S 420

6, 409

43

214

7,309

12,024

23

3, 192

7,075

15, 703

71

14,312

9, 279

13, 140

660

15, 190

16, 839

18, 946

1,410

20,833

12, 336

19, 504

1,473

22, 297

18, 914

20, 944

1,331

34,144

14, 665

20,439

1,091

60, 696

17,547

Louisiana 22, 275

1,202

Texas -. 73,866

West South Central 2,588 9,100 12,086 22, 548 37,161 38,169 58,028 55, 610 75, 333 86, 891 114,880

Montana 185

3,261

169

2,164

3,737

8,162

1,375

8

893

3,688

739

2,146

3,711

11,845

1,496

11

1,612

2,497

915

2,962

4,483

13,400

1,029

29

1,292

Idaho 5,043

823

4,841

New Alexico 3,849

Arizona 17, 406

Utah ... 1,714

133

(3) C) {') W W (') (=) (') 19,051 24, 628 26, 917 35,101

15,015

5,800

42, 270

15, 610

4,396

66, 194

18, 995

4, 945

58,439

30,367

Ore'^on 6,487

California 65,266

Pacific^ -. 20, 5.50 22, 370 20,961 27, 176 43, 057 51, 245 56, 788 67, 120 63,085 76, 199 82, 379 102,110

Continental U S 22, 397 35, 556 .53, 785 70,117 90, 697 135, ! 03 175,935 286, 575 288, 239 342, 074 370, 926 478, 475

Hawaii 4 6 410 1,048

1,032

1,097

1,042

580

0

0

2,098

0

1,643

0

742

0

634

Territories 4 6 410 2,080 2,139 580 2,098 1,643 742 634

1 otal 22, 397 35, 556 53, 789 70, 123 97,107 137, 983 178,074 287,165 290, 337 344, 317 371, 668 479,109

' Consumption not repurtnd for States omitted; 1947-55, Adams and Scholl

US); 1956-68, Adams (/O, /aj.

2 Data for individual States omitted prior to 1955 to avoid divulging private

business.

3 Total included with the Pacific total.
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION

in 1954-55 in Puerto Eico and all the States in

each region except New England, %yhere it was

nsed only in Connecticut. No consumption was

reported in 1956-57 in any of the New England

States nor in West Virginia. It was used in

Hawaii from 1948-49 through 1953-54, but since

then consumption has not been reported.

The quantity of nitrogen applied to the soil in

the form of nitrogen solutions, as shown in table

4, has increased annually since 1948^9 to a total

TABLE 4.—Nitrogen, in short tons, applied to the soil as nitrogen solutions, hy States and Territories, years ended June

30, 19Í7-58 "

State and region 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958

Maine -

TonsN Tons N Tons N Tons N Tons N Tons N TonsN Tons N Tons N

10

Tons N

16

Tons N

m

44

48

4

Tons N

67

Kew Hampshire 67

Vermont 43

Massachusetts.. .. 3

Connecticut 1 2 93

New England 11 18 97 273

New York . 48 0 0 0 0 24

42

22

33

136

108

60

389

311

194

172

201

1

517

269

181

521

228

0

322

5

387

128

106

178

0

335

0

483

Ne-.v Jersey ... .. .. . 113

Pennsylvania. 193

Delaware . 8 248

District of Columbia 0

Marvland 135 106 360

West Virginia.... 0

Middle Atlantic 48 0 0 0 8 .256 799 1,396 1,526 1,134 1 397

Virginia ... 20

70

93

300

41

24

40

15

1,047

107

43

114

744

1,960

401

404

97

974

3,699

1,206

424

581

1,860

12, 278

3,482

2,405

1,742

2 590

North Carolina .. . 11 795

South Carolina.. 4,412

Georgia. 87

140

3 592

Florida... 28 Ö 2 354 1 637

South Atlantic... ... . .. 28 0 2 354 317 498 1.326 3,606 6,884 21, 767 24 026

Ohio 64

518

1,053

232

1,369

2,061

747

1,930

1,798

101

104

681

2,394

3,190

308

129

981

2,049

2,212

409

428

1, 421

6,372

1,640

1,968

790

1,686

Indiana .. . 14 7,636

Illinois 5,533

1,639

Wisconsin 1 1 793

East North Central. . .. 14 1,635 3, 663 4,680 6,702 6,079 12,191 18 287

Minnesota 1,041

804

573

1,752

3,354

2,290

3,467

4,389

1,320

58

162

5,414

134

2,259

2, 362

1,649

26

129

4,427

260

4, 227

3,764

3,281

9

13

7,442

81

5,813

Iowa .. .. 36

197

6,726

Missouri 4,266

North Daliota 12

South Dakota 70

5,566

94

313

Nebraska 23 565

295

13, 843

Kansas 304

West North Central 256 3,278 13,125 14, 944 11,112 18,817 31,277

Kentucky 36 27 187

13

0

0

62

0

268

0

158

0

211

125

445

16

56

2,310

502

Tennessee .. . ... 38

Alabama. 140

0

0

0

226

Mississippi 12 131 120 219 0 2,240

East South Central 12 131 120 219 0 176 27 200 330 494 2,827 3,006

Arkansas 6

1,029

274

657

1,875

1,740

45

2,016

2,363

Louisiana . 62 572 291 199 268 287 360 496 2, 654

Oklahoma 57

Texas 44 39 147 458 795 1,335 1,920 3,846

West South Central... 62 572 291 243 307 434 818 1,291 2,370 2,851 5, 676 8,920

Montana. .. ... 33

710

7

303

0

3,088

9

28

119

1,978

3

316

0

2,895

87

96

158

Idaho 380 2,985

Wyoming... ...... 1

4

0

2, 259

0

161

2,124

35

0

4,046

3

51

114

0

3,797

m

8

474

New Mexico 18

205

100

222

148

712

153

1,018

375

Arizona.. ..... 52 3,106

Utah 49

Nevada 8 108

Mountain 52 223 322 860 1,171 2,263 2,293 4,135 4,300 4,178 5,494 7,256

Washington 3 0 0 0 0 0 19

23

10, 445

783

53

20, 590

4, 452

891

37,142

5,853

2,640

44, 609

8,761

8,961

51, 578

12,834

Oreeon... 7,425

California 2,764 4,781 3,514 6,173 8,663 9,187 .52, 661

Pacific 2,767 4,781 3, 514 6,173 8, 663 9,187 10,487 21, 426 42, 485 53,162 69, 300 72, 920

Continental U.S . 2,893 5, 783 4, 247 7,497 10, .509 14, 276 21,320 46. 983 76.144 86, 304 137,303 ] 67, 362

Hawaii.. 3,023

1, 398

8,480

355

10,059

640

13, 962

820

4,996

Puerto Rico.. 3 0 881

Territories.. 3 0 4, 421 8,835 10, 699 14, 782 5,877

Total 2,893 5,783 4,247 7,497 10, .509 14, 279 21, 320 51,404 84,979 07, 003 152, 085 173, 239

' Includes aqua ammonia; consumption has never been reported in Rhode Department of Agiicultmc fertilizer consinnption surveys.

Island; 1947-55, Adams and Scholl (2S); 1956-58, unpublished data from U.S. 2 Less than 1 ton.
6 AGRICULTURE HANDBOOK 19 8, U.S. DEPARTMENT OF AGRICULTURE

of 173,239 tons in 1957-58. The greatest annual

increase in consumption over the previous year

was 55,082 tons in 1956-57. No reports of consumption of nitrogen in this form in 1957-58 were

received from Rhode Island, West Virginia, and

the District of Columbia. Rhode Island is the

only State where the use of nitrogen solutions has

never been reported.

The largest quantities of nitrogen applied annually to soils as nitrogen solutions are used in

the Pacific States. Annual consumption in this

region amounted to more than 50 percent of the

total annual consumption in continental United

States from 1946-47 to 1956-57, except in 1952-53,

and 1953-54. Nitrogen solutions were used in the

West North Central States for the first time in

1951-52. Starting in 1953-54 annual consumption in this region has ranked second to that in

the Pacific States except in 1956-57, when the

South Atlantic States took over second place. The

first use of nitrogen solution in New England was

in 1954-55 ; only token amounts were used in five

States of this region in 1957-58.

CHARACTERISTICS OF LIQUID NITROGEN MATERIALS

As of August 1, 1957, 53 nitrogen solutions

{11) were listed as available to the fertilizer trade

in addition to anhydrous ammonia and aqua ammonia. Other solutions are now also listed, and

some of the original solutions are being produced

by additional companies. Some liquid nitrogen

materials are used only for direct application,

some for direct application and for making mixed

fertilizers, and others—not discussed in this publication—are used only for the latter purpose.

Generally, each liquid nitrogen material is manufactured by more than one company and each

company produces several different liquids. The

products of one company are distinguished from

those of another by a combination of the company

name with "Nitrogen Solution," "Aqua Ammonia," or "Anhydrous Ammonia," or by trademark names registered in tlie U.S. Patent Office.

The registered names in 1957 {11) were Amanol,

Bay-Sol, Brea, Dixsol, Elephant, Feran, Lion,

Nisol, Nitrana, Ortho, Phillips 66, Sodan, Sohiogen, Spensol, Steamboat, U.A.S., Uramon, Uran,

and Urana.

Liquid nitrogen materials can be classified arbitrarily on the basis of their vapor pressures

(pounds-per-square-inch gage) at 104° F. into

nonpressure (0 pound), low-pressure (0-19

poimds), medium-pressure (20-100 pounds), and

high-pressure (above 100 pounds) liquids.

The nonpressure (NP) liquids are ac][ueous solutions of nitrogen salts and contain no neutralizing

ammonia. The solutions contain one or two of the

following sources of nitrogen—ammonium bisiilfite, ammonium nitrate, calcium nitrate, urea.

They are sold primarily for direct epplication to

the soil.

Aqueoiis solutions of ammonia alone or with

ammonium nitrate or urea, singly or in combination, comprise the low-pressure (LP) and mediumpressure (MP) liquids. The pressure solutions

have been used for several decades for ammoniation of superphosphate and mixtures containing

superphosphate. They have also been used for

direct application in recent years, but this use

lias been limited almost exclusively to those containing approximately 41 percent or less nitrogen.

The more concentrated liquids can be used for the

same purpose under favorable temperature conditions or after dilution.

Anhydrous ammonia is a high-pressure (HP)

liquid and supplies the greatest tonnage of nitrogen applied to the soil in the form of liquid nitrogen materials.

A nomenclature system for nitrogen solutions

has been suggested (5, 135) and has Seen adopted

by some of the commercial producers. The proposed system includes in the following order:

(1) The company trade name, (2) the percent

total nitrogen with the percentage point omitted,

and (3) in brackets, the percentage composition

of ammonia, ammonium nitimte, urea, and any

other significant source of nitrogen, all rounded

off to the nearest Avhole number and in the sequence

given. For example, a materiarlabeled 403 [20-

16-4] would be a nitrogen solution containing

40.3 percent total nitrogen, 20 percent ammonia,

16 percent ammonium nitrate, and 4 percent urea.

Compositions

The chemical composition, salting-out or crystallization temperature, and calcium carbonate

equivalent of the listecl commercial liquid nitrogen

materials are given in table 5. The tabulated data

are representative of each type of liquid and may

vary slightly from the compositions reported by

individual manufacturers. These variations are

no greater than the variations in the composition

of batches of the same type of solution produced

by one company or by different companies.

Liquid nitrogen materials are comprised of

anhydrous ammonia and water solutions of ammonia, ammonium salts, and urea singly or in combination. At present all contain ammoniacal nitrogen. Ammonium nitrate is the only salt

supplying ammoniacal nitrogen in any of the solutions except NP-1 and MP-8. Ammonium bisulfite is the source in NP-1 and ammonium sulfate

in MP-8. Urea supplies additional nitrogen in

many of the solutions. Calcium nitrate is the

source of some of the nitrogen in NP-3 and sodium

nitrate supplies some in NP-6. Solutions LP-13,

MP-8, -10, and -12 contain carbon dioxide.
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION 7

TABLE 5.~Ohemioal composition and properties of liquid nitrogen materials available for fertilizer use, in 1959 ^

Product Composition Nitrogen content Calci rm car1 Saltingbonate equlvDesignation Am- Ammonia N out Dounds of— Ammonia

monium Urea Water

Nitrate

N

Urea

N

Total

N

tem- Kind peraPressure Suggested nitrate Free Com- Ma- Nitrobined terial gen

NP-1

N'P-2

NP-3

85(0-0-0-60 ']

160(0-46-0]

170(0-31-0-36 3]

NonpreSsure liquids

Pet. Pd. Pd. Pd.

40.0

54.3

32.9

Pd. Pet.

8.5

8.0

6.4

Pd. Pd. Pd.

8.5

16.0

17.0

° F.

32

Lb.

45.5

28.8

11 3

Lh.

535

180

66

45.7

30.9

8.0

11.6 NP-4 175(0-50-0] 50.0 50.0 8.7 8.8 17 5 31.5

34.2

23.8

36.0

180

180

119

180

180

NP-5 190(0-54-0] 54.3 46.7 9.6 9 6 19 0 34

Aqueous solutions ot

nitrogen products.

NP-6

NP-7

NP-8

200(0-48-0-

200(0-57-0

210(0-60-0

20 <] 47.5

57.3

60.0

32.0

42.7

40.0

8.3

10.0

10. 5

11.7

10.0

10. 5

20.0

20.0

21 0

58

42

NP-9 227 0-65-0 65.0 35.0 11.4 11.3 22.7 40 9 180 NP-10 245 0-70-0 70.0 30.0 12.3 12.2 24.5 44 1 180 NP-11 280(0-40-301 39.5 30.5 30.0 6.9 6.9 14.2 28.0 1 50 4 180 NP-12 300(0-42-331 42.2 32.7 26.1 7.4 7.4 15.2 .30.0 15 36 0 180 ^NP-13

LP-1

/LP-2

320(0-44-35] 44.3 35.4 20.3 7.7 7.8 16.6 32.0 32 57.6 180

Low-pressure liquids

Aqua ammonia 206

370

(25-0-01 25.0

16.6

76.0

16.6

20.6

13.6

20.6

37.0

-103

48

37.1

66.6

180 17-67-0 66.8 11.7 11.7 180 LP-3 410 19-72-0 19.0 72.5 8.5 15.6 12.7 12.7 41.0 61 73.8 180 LP-4 410 22-65-0 22.2 65.0 12.8 18.3 11.4 11.3 41,0 21 73 8 180 LP-5 410 24-60-0 24.3 60.0 15.7 20.0 10.5 10.6 41.0 1 73 8 180 Ammonia—ammoni- LP-6 4iU 26-56-0 26.3 55.5 18.2 21.6 9.7 9.7 41.0 — 25 73 S 180

um nitrate solutions. LP-7 414 19-74-0 19.0 74.0 7.0 15.6 12.9 12.9 41.4 64 74. 6 180 LP-8 434 23-70-0 23.0 70.0 7.0 18.9 12.2 12.3 43.4 32 78. 1 180 LP-9 440 24-70-0 23.8 69.8 6.4 19.6 12.2 12.2 44.0 26 79. 2 180 LP-10 448 25-69-0 25.0 69.0 6.0 20.6 12.1 12. 1 44.8 6 80 6 180 Ammonia-urea solu- LP-11

LP-12

LP-13 •

/LP-14

lLP-15

210

350

371

410

(4-0-38]

20-0-41

25-0-35

19-58-111

4.3

19.6

25.0

19.0 '"ss.'o"

37.5

40.6

35.3

11.0

58.2

39.8

23.3

12.0

3.5

16.1

20.6

15.6

17.6

18.9

16.5

5.1

21.0

35.0

37.1

41.0

33

68

34

7

37.8

63.0

66.8

73.8

tions. 180

Ammonia-ammonium 10.1 10.2 180 nitrate-urea solu- 414 19-66-6] 19.0 66.6 6.0 9.4 15.6 11.5 11.5 2.8 41.4 36 74. 5 180 tions.

/MP-1

Medium-pressure liq aids

440(28-60-0 28.0 60.0 12.0 23.0 10.5 10.5 44.0 -36 79.2 180 MP-2 451 26-68-0 26.0 68.0 6.0 21.3 11.9 11.9 45.1 -6 81.2 180

Ammonia-ammonium MP-3 452 30-59-0 29.9 59.0 11.1 24.6 10.3 10.3 45.2 -27 81.4 180

nitrate solutions. MP-4 471 30-64-0 30.0 64.0 6.0 24.7 11.2 11.2 47.1 -32 84.8 180

MP-5 490 34-60-0 34 0 60.0 6.0 28.0 10.5 10.5 49.0 -61 88.2 180

MP-6 500 40-50-0 39.6 50.0 10.4 32.5 8.7 8.8 50.0 -85 90.0 180

MP-7 508 43-45-0 42.6 45.0 12.4 35.0 7.9 7.9 50.8 -96 91.4 180

'MP-8« 425 27-0-39-10 '] 27.1 38.8 15.1 22.3 2.1 18.1 42.5 20 82.5 194

MP-9

AlP-lOS

MP-U

453

453

4.54

31-0-43

30-0-43

37-0-32

30.6

30.5

36.8

43.1

43.3

32.5

26.3

17.6

30.7

25.2

25.1

30.3

20.1

20.2

15.2

45.3

45.3

45.4

46

34

16

81.5

81.6

81 8

180

Ammonia-urea solu- 180

tions. 180

MP-12» 4,55 37-0-32 36.8 32.6 24.8 30.3 15.2 45.5 5 81.9 180

MP-13

MP-14

460

460

31-0^4

37-0-33

31.1

37.3

43.8

32.9

25.1

29.8

25.6

30.7

20.4

15.3

46.0

46.0

41

1

82.8

82.8

180

180

/MP-15 430 20-68-6 20.0 68.0 6.0 6.0 16.4 11.9 U.9 2.8 43.0 14 77.4 180

MP-16 440 22-66-6 22.0 66.0 6.0 6.0 18.1 11.5 11.6 2.8 44.0 -17 79.2 ISO

MP-17 440 28-40-15 28.0 40.0 15.0 17.0 23.0 7.0 7.0 7.0 44.0 1 79.2 180

MP-18 444 24^56-10 24.5 56.0 10.0 9.5 20.2 9.8 9.8 4.6 44.4 -15 79.9 180

Ammonia-ammonium MP-19 444 25-55-10 25.0 65.0 10.0 10.0 20.6 9.6 9.6 4.6 44.4 -20 79.9 180

nitrate-urea solu- MP-20 444 26-50-12 26.0 50.0 12.0 12.0 21.3 8.7 8.8 5.6 44.4 -7 79.9 180

tions. MP-21 452 30-51-61 29.9 51.0 6.0 13.1 24.6 8.9 8.9 2.8 45.2 -8 81.4 180

MP-22 455 26-4^18] 26.0 45.0 18.0 11.0 21.3 7.9 7.9 8,4 45.6 15 81.9 180

MP-23 490 33-45-13] 33.0 45.0 13.2 8.8 27.1 7.9 7.9 6,1 49.0 -13 88.2 180

MP-24 491 34-43-13] 34 0 43.0 13.0 10.0 28.0 7- 5 7.5 6,1 49.1 -5 88.4 180

MP-25

PIP-1

496(37-40-11]

822 M 00-0-01

37.0 40.0 11.0 12.0 30.4 7.0 7.0 5,1 49.6 89.1 180

High-pressure liquids

Anhydrous ammonia 99.9 82.2 82.2 148,0 180 1

' Each product represents one or more similar commercial products; slight

variations occur in the published data for similar liquids.

' Estimated to contain 60 percent ammonium bisulfite.

' Contains 36.2 percent calcium nitrate.

' Contains 20.5 percent sodium nitrate.

5 Contains 8.4 percent carbon dioxide and 8.0 percent formaldehyde.

' Contains 9.0 percent carbon dioxide and 10.0 percent ammonium sulfate.

' Contains 10.0 percent ammonium sulfate.

' Contains 8.6 percent carbon dioxide.

• Contains 5.9 percent carbon dioxide.

586670 O—61-
8

AGRICULTURE HANDBOOK 198, U.S. DEPARTMENT OF AGRICULTURE

Anhydrous ammonia is often diluted to produce

the low-pressure aqua ammonia (LP-1), wliicli

does not require the liigh-pressure storage and

application equipment for the deep-phxcement application necessary for the anliydrous material.

LP-1 is representative of a number of grades of

commercial aqua ammonia.

The nitrogen content of the liquid nitrogen fertilizers ranges from 8.5 percent in NP-1 to 82.2

percent in HP-1. The nonpressure solutions, with

two exceptions, contain less than 30 percent nitrogen whereas the low-pressure solutions, except

LP-1 and LP-11, contain between 30 and 45 percent. The medium-pressure liquids, with two exceptions, contain 44.0 percent or more nitrogen.

Chemical Properties

A number of chemical properties are important

to the use of liquid nitrogen fertilizers. The

liquids are corrosive, many support combustion,

and some may form explosive mixtures Avith oxygen. Other important properties are crystallization temperature, physiological acidity developed

in the soil, and forms of nitrogen—ammoniacal, nitrate, and urea-nitrogen.

jNIost of the common metals are not affected by

dry ammonia, but the presence of moisture will

cause the ammonia to react rapidly with copper,

brass, zinc (galvanized equipment), and many

alloys, especially those containing copper (62).

Iron and steel are not affected by moist ammonia,

and equipment made of these materials can be

used with anhydrous and aqua ammonia.

The other solutions can also be handled in ordinary steel, but corrosion occurs and shortens the

life of the equipment (60). Equipment made of

aluminum, of many of the essentially copper-free

aluminum alloys, or of certain stainless steels is

recommended for solutions containing dissolved

nitrogen salts (U7). Vreeland and Kalin (198)

studied the corrosion of metals in solutions NP-8

and LP-4 by partially immersing 1-inch by 2-inch

specimens in the solution being tested. Each specimen was tested separately. The corrosion rates,

as calculated from the weight losses, are given

in table 6. They indicate that chromium stainTABLE 6.—Corrosion rates of metals in nitrogen solutions '

Metal

Carbon steel

Chromium stainless steel:

Type 502 (5,2 percent Cr)

406 (12.5 percent Cr)

430 (17.1 percent Cr)

Nickel stainless steel:

Type 304 (9.0 percent Ni, 18.9 percent CT)

316 (12.9 percent Ni, 18.0 percent Cr)

Aluminum alloy, type 3003-H14 (1.15 percent Mn)

1 Data from Vreeland and Kalin (.I9S).

2 Calculated from weight loss.

» At 100° F. for 28 days.

< At 100° F. for 14 days.

5 Not tested.

Corrosion rate ' (mils

penetration per

month) for—

less steel, type 405, nickel stainless steel, type 304,

and aluminum alloy, type 3003-H14, should be

suitable for liquid nitrogen fertilizer containers.

Ammonium thiocyanate is used generally as a

corrosion inhibitor in liquid nitrogen solutions.

At concentrations greater than 0.1 percent by

weight, the corrosion of cold-rolled, niild steel

at 86° F. is only about 0.5 percent the uninhibited

rate. The corrosion rate is further reduced by

the addition of sodium arsenite (93). Other materials belonging to the general class of compounds

containing divalent sulfur linked to carbon (38,

3d., Ill), other trivalent arsenic compounds (37),

and sodium dichromate (36) have been suggested

for reducing corrosion.

Attempts have also been made to combat) corrosion by coating equipment with natural or synthetic rubber, glass, suitable plastic material, and

corrosion-resistant metal. Rubber containers with

capacities up to 15,000 gallons are also available,

as well as rubber liners for metal tanks.

Anhydrous ammonia and its aqueous solutions

present fire and explosion hazards (66, 131, 133,

llfS, H7, llfd). Ammonia-air mixtures containing

16 to 25 percent ammonia by volume and ammoniaoxygen mixtures containing 15 to 79 percent ammonia will explode when ignited. The exploSIV& range is broadened by elevated temperatures

and pressures higher than atmospheric. The presence of oil or other combustible materials increases

the hazard. Mercury forms explosive compounds

with ammonia and accelerates the corrosion of

aluminum containers.

Solutions containing ammonium nitrate, a vigorous oxidizing agent, are substantially nonhazarclous so long as the nitrate remains in solution.

The solid salt, however, presents serious fire and

explosion hazards (71, 132, 169), especially when

in contact with combustible materials. The presence of urea in the solutions does not add to either

of these hazards, but sodium nitrate contributes

to the fire risk.

Anhydrous ammonia has been handled to a limited extent in butane and propane tanks, although

hydrocyanic acid has been reported to be formed

when mixtures of butane or propane and ammonia are burned (25). This is a controversial

subject (191) that has not been settled, and every

effort should be made to avoid the possibility

of danger. When ammonia is mixed rapidly with

a strong inorganic acid, the mixture boils and

may overflow or rupture the container.

The salting-out temperature is the temperature

at which crystals begin to form in the liquid. It

is one of the important characteristics to be considered in selecting a liquid nitrogen fertilizer.

Liquids with salting-out temperatures above

prevailing air temperatures will salt out and cause

equipment failure and uneven distribution. Particular attention must be paid to this factor durino' the changing seasons. Anhydrous and aqua
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION 9

ammonia, solutions LP-1 and LP-6, and some of

the medium-i^ressure solutions can be api^lied any

time it is possible to work the soil. Solutions

with high ,saltirig-out temperatures, such as NP-6,

NP-8, and LP-^7, cannot be recommended for

use during cold weather unless they are diluted

to prevent salting out.

The effect of dilution of some typical nitrogen

solutions is given in table 7. The addition of

water depresses the salting-out temperature in

each case. The depression is continous with dilution in the examples given, and in three cases the

addition of 15 gallons of water to 100 gallons

of solution reduces the salting-out temperature

to the freezing point of water or below. The

lower salting-out temperature increases the area

and widens the temperature range over which a

solution can be used.

TABLE 7.—Effect of dilution on the nitrogen content and salting-out temperatures of typical nitrogen fertilizer liquids ^

Product designation

Original liquid

3 gallons of water

added to 100 gallons

of liquid

5 gallons of water

added to 100 gallons

of liquid

10 gallons of water

added to 100 gallons

of liquid

15 gallons of water

added to 100 gallons

of liquid

Nitrogen

content

Salting-out

temperature

Nitrogen

content

Salting-out

temperature

Nitrogen

content

Salting-out

temperature

Nitrogen

content

Salting-out

temperature

Nitrogen

content

Salting-out

temperature

NP-6 -

Percent

20.0

21.0

32.0

37.0

41.0

° F.

58

51

32

56

21

Percent

19.6

20.6

31.2

36.1

39.8

" F.

54

48

24

50

19

Percent

19.4

20.2

30.8

35.6

39.2

° F.

51

45

21

48

18

Percent

18.7

19.5

29.8

34.2

37.7

» F.

44

38

12

42

16

Percent

18.1

18.8

28.8

33.0

36.2

° F.

36

NP-8 32

NP-13.-

LP-2 _..

5

37

LP-4 15

> Data from U.S. Department of Agriculture (193).

The liquid nitrogen fertilizers are physiologically acid and leave an acid residue in the soil.

The potential decrease in soil pH resulting from

the use of these liquids is evaluated in terms of

the pounds of calcium carbonate necessary to neutralize the resulting acid residue [loJ^). The general requirement, as shown in table 5, is 180

pounds of calcium carbonate per 100 pounds of

nitrogen applied to the soil.

Physical Properties

Physical propertes of liquid nitrogen fertilizers

are given in table 8. The tabulated properties

include the vapor pressures at four different temperatures, the temperature at which the gage pressure becomes zero, specific gravity, the "weight of

a gallon of liquid, the weight of nitrogen contained therein, and the volume of liquid per

100 pounds of nitrogen. Additional properties

of anhydrous ammonia are given in table 9. Further information on the properties of nitrogen

solutions have been reported by Shultz and Elmore {172) and Worthington, Datin, and Schutz

(201). The former determined the vapor pressures of experimental ammonia-ammonimn nitrate-Avater solutions and the partial pressures of

the ammonia and Avater at 10° and 35° C.

Worthington and coworkers reported data on the

solubilities, vapor pressures, and densities of ammonia-ammonium nitrate-Avater and ammoniaurea-Avater solutions in the ranges of 0 to 65 percent ammonia, 0 to 75 percent ammonium nitrate,

and 0 to 65 percent urea.

TABLE 8.—Physical properties of liquid nitrogen materials available for fertiliser use in 1959 ^

Product

Nitrogen

content

A'apor pressure (gage) at— Temperature at

which

gage

pressure

isO

Specific

gravity

at

60° F.

AVeight

of solution

per

gallon

at

60° F.

AVeight

of

nitrogen per

gallon

at

60° F.

A^olume

per 100

pounds

Kind

Designation

60° F. 90° F. 104° F. 120° F.

of

nitrogen at

Pressure Suggested

60° F.

XP-1

.\P-2

XP-3

NP-4

XP-5

NP-6

XP-7

\P-8

NP-9

.XP-10

NP-11

.\P-12

XP-13

85[0-0-0-60J

16010-46-0]

170 0-31-0-36]

175 0-50-0

190[0-54-0

200 0-48-0-20]

200 0-57-0

210 0-60-0

227 0-6.5-0

245 0-70-0

280[0-40-30]

300 0^2-33

320(0-44-35

X'onpressure liquids

Percent

8.5

16.0

17.0

17.5

19.0

20.0

20.0

21.0

22.7

24.5

28.0

20.0

32.0

P.s.i. P.s.i. P.s.i. P.s.i. °F.

1.28

1.208

2 1.499

1.225

1.254

1.410

2 1.263

1.287

1.307

'1.346

1.278

1.300

1.3L'7

Pounds

10.67

10.07

312. 50

10. 22

10.46

11. 76

310. 53

10.73

10.90

11.23

10.66

10, 84

11.07

Pounds

.91

1.61

3 2.15

1.79

1.99

2.35

3 2.11

2. 25

2.47

2.75

2.98

3.25

3.54

Gallons

109.9

62.1

3 46.5

55.9

50.3

42.6

Aqueous solutions of nitrogen products. 3 47.4

44.4

40.5

36.4

33.6

30.8

28.2

See footnot<'.s at end of table.
10 AGRICULTURE HANDBOOK 198, U.S. DEPARTMENT OF AGRICULTURE

TADI.E H.—riiysicnl properties of li(¡in<l nitrogen materials available for fertilizer use in 1959 '—Continnea

Product

Kind

Aqua ammoniaAmmonia—ammonium nitrate solutions.

Ammonia—urea solutionsAmmonia—ammonium nitrate—urea

solutions.

A mmonia—ammonium nitrate solutions.

Ammonia—urea solutionsAmmonla—ammonium nitrate—urea

solutions.

Anhydrous ammonia.-- -- HP-1

Designation

Pressure

LP-1

LP-2

LP-3

LP-4

LP-5

LP-fi

LP-7

LP-8

LP-9

lLP-10

LP-11

LP-12

LP-13

/LP-14

lLP-15

/MP-1

MP-2

MP-3

MP-4

MP-5

MP-6

,MP-7

'MP-8

MP-9

MP-10

MP-11

MP-12

MP-13

,MP-14

'MP-15

MP-16

MP-17

MP-18

MP-19

(MP-20

MP-21

MP-22

MP-23

MP-24

.MP-25

Suggested

206[25-0-0]

370 17-67-0]

410 19-72-0]

410

410

410

210

3S0

371

22-65-0

24-60-0

26-56-0

414 19-74-0

23-70-0]

24-70-0]

448 25-69-0]

4-0-38)

20-0-41]

25-0-35)

410 19-.58-11]

414(19-66-61

440Í28-60-O

451126-68-0

452]30-59-O'

471

490

600

508

425

453

453

30-64-0

34-60-0

40-50-0

43-45-0

27-0-39-10]

31-0-43

30-0-43'

455

460

460

430

440

440

444

444

444

454 37-0-32

37-0-32

31-0-44

37-0-33'

20-68-6

22-66-6

28-40-15]

25-56-10

25-55-10]

26-50-12]

452 30-51-6]

455 26-45-18

33-45-13

34-43-13

495(37-40-11

822(100-0-0]

Nitrogen

content

Percent

20.6

37.0

41.0

41.0

41.0

41.0

41.4

43.4

44.0

44.8

21.0

35.0

37.1

41.0

41.4

Vapor pressure (gage) at

60° F.

82.2

90° F. 104° F. 120° F.

Tem Weight Weight

pera- of solu- of

ture at Specific tion nitrowhich gravity per gen per

gage at gallon gallon

pres- 60° F. at at

sure 60° F. 60° F.

iso

Volume

per 100

pounds

of

nitrogen at

60° F.

Low-pressure liquids

P.s.i.

-9

-9

-6

-5

P.s.i.

-3

-3

2

6

-3 8

-3 3

-2 10

0 9

-5 3

-2 10

-6 4

92

P.s.i.

2

1

7

10

P.s.i.

8

7

15

19

101

86

79

70

29 68

18 78

29 67

29 60

18 81

24 65

18 80

0.911

1.182

1.194

1.139

1.100

1.078

1.186

1.16

1.147

1.124

1.085

1.020

1.05

1.161

1.178

Pounds

7.60

9.86

9.96

9.50

9.17

9.67

9.56

9.37

9.05

8.51

8.76

9.68

9.82

Pounds

1.66

3.65

4.08

3,89

3.76

3.69

4.09

4.20

4.21

4.20

1.90

2.98

3.25

3.97

4.06

Medium-pressure liquids

High-pressure liquids

166 211 276 -28 0.618 5.15

44.0 1 15 25 39 57 1.083 9.03 3.97

45.1 0 13 24 36 60 1.124 9.37 4.23

45.2 '4 »20 26 i 55 '54 1.070 8.92 4.03

47.1 5 22 30 46 47 1.095 9.13 4.30

49. Ü 10 32 50 71 39 1.044 8.71 4.27

50.0 58 992 8 26 4 13

60.8 24 53 72 99 6 .984 8.21 4.17

42 5 15 1.13 9.42 4.00

45.3 13 32 48 65 .973 8.11 3.67

45.3 16 40 65 74 28 1.06 8.84 4.00

45.5 15 40 57 79 29 .927 7.73 3.52

45.5 23 53 71 96 10 .99 8.26 3.76

46.0 13 36 61 70 31 .972 8.11 3.73

46.0 19 42 60 82 22 .927 7.73 3.56

43. 0 1 14 22 31 57 1.165 9,72 4.18

44.0 4 18 27 36 54 1.149 9.57 4.21

44.0 3 18 27 45 52 1.052 8.77 3.86

44.4 -1 12 22 35 62 1.108 9.24 4.10

44.4 1 13 22 34 55 1.111 9.26 4.11

44.4 1 15 24 37 54 1.081 9.01 4.00

45.2 58 »19 27 »50 »56 1.057 8.82 3.99

45.5 3 28 42 56 1.089 9.08 4.13

49.0 12 34 50 69 35 1.034 8.62 4.22

49.1 12 62 74 35 1.012 8.44 4.14

49.5 60 1.039 8.66 4.29

:.23

25.2

23.6

24.8

23.3

23.4

24,2

24,0

25,0

27,2

25.0

28.4

26.6

26.8

28.1

23.9

23.8

25,9

24,4

24.3

25.0

25.1

24.2

23.7

24.2

23,3

23,1

1 Each product represents one or more similar commercial products; slight

variations occur in the published data for similar liquids,

2 At 68° F,/60° F.

3 At 68° F.

< At 70° F,

» Estimated by producer.

TABLE 9.—Physical properties of anhydrous ammonia '

Boiling point at 1 atmosphere —28° F.

Melting point at 1 atmosphere —107.9° F.

Critical temperature 271.4° F.

Critical pressure 1,657 p,s,i.a.

Vapor density at —28° F., 1 atmosphere 0.0555 Ib./cu. ft.

Liquid density at —28° F., 1 atmosphere , 42.57 Ib./cu. ft.

Specific volume of vapor at 32° F,,

1 atmosphere 20,78 cu, ft./lb.

Range of explosive ammonia-air

mixtures , 16-25 percent NH3, by volume

Ignition temperature (iron bomb)- 1,204° P.

Specific heat, Cp (1 atmosphere,

60° F,) 0,52 B,t,u,/lb,/°F,

Solubility in water at 1 atmosphere and 32° P 0,899 g, NH^/g, water

68° F 0,518 g. NHj/g, water

104° F 0,338 g. NHs/g, water

140° F 0,238 g, NHj/g, water

1 Data from Nitrogen Division, Allied Chemical & Dye Corp.

(ii9).

The gage pressures of the commercial liquid

nitrogen fertilizers cover a range of —9 pounds

per square inch at 60° F. to 276 pounds at 120°.

The gage pressures are 0 or below at 60° for all

the low-pressure solutions and 0 or above for all

the medium- and high-pressure liquids, except

solution MP-18. All the liquid nitrogen fertilizers have gage pressures of 0 or above at 104°.

Solutions LP-2 and LP-11 are the only liquids

with a vapor pressure of 0 at a temperature over

100°. The temperature of liquid HP-1 must drop

to —28° before the gage pressure is reduced to 0.

Anhydrous ammonia has the lowest specific

gravity and is the most concentrated of any of the

liquid nitrogen materials. However, three solutions—MP-4, -5, and -25—contain more nitrogen

per gallon than anhydrous ammonia.
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION 11

The weight of nitrogen per gallon is one of the

important characteristics of the various liquid

nitrogen materials. A 100-gallon liquid anhydrous

ammonia container, which in practical use should

not be filled to more than 90 percent of capacity,

has a carrying capacity of 381 pounds of nitrogen. The same size tank has a carrying capacity of 354 pounds of nitrogen in the form of

solution NP-13 and over 400 pounds of nitrogen in several LP and MP solutions. The tanks

and metering devices for these solutions are much

lighter and less costly than those required for anhydrous ammonia. Because of the difference in

weight of equipment, the weight of nitrogen carried per pound of loaded equipment will be

greater for some solutions than for anhydrous

ammonia.

Physiological Properties

The ammonia in any of the liquid nitrogen

fertilizers is a health hazard, but undue exposure

to an atmosphere seriously contaminated with

ammonia is unlikely because of its pungent odor

and suffocating effect. The physiological effects

and remedial treatments have been discussed in

many publications, including those of the Manufacturing Chemists' Association, Inc. (131, 133)

and various ammonia producers {61, 75, llf.9, 153,

180).

The magnitude of the hazard is commensurate

with the ammonia concentration of the liquid nitrogen fertilizer. The critical concentrations are

given in table 10. The symptoms resulting from

exposure to ammonia gas may be nausea, vomiting, pain in the throat and abdomen, weak and

rapid pulse, convulsions, burning of the eyes, and

coughing.

TABLE 10 —Critical gaseous ammonia concentrations '

Concentration

(parts per

million)

Effects on unprotected

worker Exposure period

50 Least detectable odor

No adverse effects for average unprotected worker.

Causes irritation of throat.,.

Causes irritation of eyes

Causes convulsive coughing.

Causes respiratory spasm,

strangulation, asphjTtia.

100.

ing exposure.

400 Ordinarily no serious results following infrequent

short exposures (less than

1 hour).

700..

1,720. No exposure permissible

(may be fatal after short

exposure—less than half an

hour).

No exposure permissible,

rapidly fatal.

5,000 to 10,000.

' Data from Manufacturing Chemists' Association, Inc. {ISS).

Ammonia gas dissolves readily in the perspiration of the body and causes a caustic burn that

varies in severity with the concentration of ammonia and the length of time of exposure.

A 2-percent concentration is generally the maximum tolerated by the skin for more than a few

seconds. Liquid anhydrous ammonia produces

severe burns on contact with the skin, caused not

only by its caustic action but also by the freezing

effect produced by the rapid evaporaton of the

liquid.

Employees working where ammonia hazards

exist should be fully informed of the dangers

and instructed in the precautions to be taken and

in first aid treatment. They should be provided

with approved gas masks, rubber hats, suits,

gloves, and boots and should wear cotton garments

under the rubber clothing. Easily accessible

safety showers and bubble fountains should be

available.

A person overcome or burned by ammonia

should be placed under the care of a physician.

Immediately apply artificial respiration if asphyxiation has occurred. "When breathing is

weak, administer oxygen or mixtures of oxygen

with 5 percent or less of carbon dioxide. Never

try to give anything by mouth to an unconscious

person. "\'\naen skin is exposed to ammonia, wash

the affected areas repeatedly with water and follow with an application of 2 percent boric acid

or acetic acid solution, lemon juice, or vinegar.

More water is then applied. Eyes injured with

ammonia should be immediately flooded with

water or 2 percent boric acid solution. This

should be continued for at least 15 minutes, after

which 2 or 3 drops of an aqueous topical anesthetic

can be applied. When throat and internal exposure occurs, have the victim drink large quantities of water followed by harmless weak acid

solutions such as lemonade and dilute vinegar. If

ammonia has been swallowed, administer a demulcent such as raw Qgg, milk, cream, barley water,

or olive oil.

The ammonium nitrate in liquid nitrogen fertilizers is also toxic to humans. Van Arsdell {196)

states that ingestation of ammonimn nitrate severely irritates the stomach and may produce

death within 20 minutes to 5 hours. Ingested

nitrate should be diluted immediately with large

quantities of water and the stomach should be

thoroughly washed. Starch and flour water, milk,

and e^gg white may be swallowed to absorb some

of the free nitrate ions.

Liquid nitrogen fertilizers, because of their ammonia, ammonium nitrate, and urea contents, may

be toxic to livestock. Animals will lick up excess solutions left on application equipment and

the salts left after evaporation of the solutions.

Boyd, McLachlan, and Perry {1^9) have shown

that/ftmmonia poisoning may be fatal to animals.

It is associated witli a series of comj^lex changes

in the chemistry of the body and particularly

of the respiratory tract.

Nitrate poisoning of cattle, sheep, and horses

may occur when they have access to nitrate fertilizer, which is quite j^alatable, especially to cattle {If2). Tlie ingested nitrate is reduced to the

highly toxic nitrite by bacterial o; enzymatic

action within the digestive tt';i<f of the animal.

The nitrite prevents the red blood cells from carrying oxygen to the tissues by changing the oxy-
12 AGRICULTURE HANDBOOK 19 8, U.S. DEPARTMENT OF AGRICULTURE

hemoglobin to methemoglobin. Immediate intravenous injection of méthylène blue helps to

counteract the effect of the nitrite by converting

tlie methemoglobin into hemoglobin.

Osebokl (10^) reported two cases of urea poisoning in cattle resulting from ingestion of urea fertilizer and other cases in Avhich the cattle were fed

portions of poorly mixed grain rations with high

urea concentrations. Chronic organic dysfunctions were detected in some cases. Reports of

urea toxicity to sheep have also been received

{78). The danger is alleviated when the animal

has access to water and can quickly excrete the

excess urea.

MANUFACTURING PROCESSES AND FACILITIES

Aside from a small cjuantity of aqua ammonia

obtained as a byproduct of coke manufacture

(67,150, ISJf), the domestic output of liquid nitrogen materials is based on ammonia manufactured

by the direct synthesis process. The ammonia, in

turn, is the parent compound of the other nitrogenous constituents.

Synthetic ammonia is produced by a catalyzed

reaction between nitrogen and hydrogen at elevated temperatures and pressures (67, S3, llß, 159,

IfHf, 195). The hydrogen is produced principally

by reactions of steam and air with carbonaceous

materials such as coke, fuel oil, natural gas, and

oil-refinery gas. Other ways in which hydrogen

is obtained include recovery from coke-oven and

petroleum-refining gases—as a byproduct of

caustic soda-chlorine manufacture—and by electrolysis of water.

Air is essentially the sole source of the nitrogen

used in the production of synthetic ammonia. The

nitrogen is obtained from (1) the producer gaswater gas reaction, (2) direct combustion of air,

(3) flue gas, (4) fractionation of liquid air, and

(5) the nitrogen-rich tail gas from ammonia oxidation plants.

The first commercial process for producing synthetic ammonia was the Haber-Bosch process,

which went into commercial operation in Germany in 1913. The synthesis takes place at a

pressure of 200 atmospheres and a temperature of

1022° F. (550° C.) over a promoted iron catalyst.

Many of the processes developed since 1913 for

the production of synthetic ammonia are based on

the Haber-Bosch process.

The processes used in the Ignited States and

Canada employ the promoted iron catalyst and

are characterized primarily by differences in the

operating temperatures and pressures. Table 11

TABLE 11.—Sijnthetic ammonia prodtiction processes'^

Process

Operating

Pressure Temperature

Atm.

300

400

250

200

950-1,000

820

100-200

300

300

°F.

887

752

752-932

932

896-932

977-1,022

752-797

932

977

"C.

475

400

400-500

500

480-500

625-550

Moiil Cf-Tiis 400-425

M. W. Kellog 500

Nitrogen Engineering Corp 610-526

lists the various processes and some of the characteristics of each.

The reported annual productive capacity of the

22 anhydrous ammonia plants in the United

States in August 1950 was 1,655,000 tons of nitrogen (table 12). There were no plants in either the

Kew England or Mountain States and only one

each in the South Atlantic and West North Central States. Six plants with a productive capacity of 462,000 tons of nitrogen were located in the

West South Central States. Expansion in a little

over 9 years increased the nmnber of plants (in

existence or under construction) to 59 and the

annual productive capacity to 4,246,000 tons of

nitrogen. At least 1 plant is located in each

region. In the West South Central States, 12

plants have a productive capacity of 1,141,000

tons of nitrogen.

TABLE 12.—Nvniher and estimated annual productive capacity of domestic anhydrous ammonia plants August

1950, and of plants existing or under construction January 1,1960, hy regions

August, 1950 ' January 1, 1960 ^

Region

Plants Productive

capacity

Plants Productive

capacity

Number 1,000 short

tons N

Number

1

9

3

7

6

7

12

3

11

1,000 short

tons N

36

Middle Atlantic

South Atlantic

4

1

3

1

3

6

371

240

184

140

146

462

582

459

East North Central 574

West North Central .. 407

East Soutii Central 429

West South Central 1,141

83

Paciflc .- , 4 Ü3 535

Total 22 1,655 59 4,246

Data from Taylor (ÍS4, p. 46).

1 Based on Taylor {18i, p. J,6).

2 Derived from table 13.

Figure 1 and table 13 show that the productive

facilities are rather evenly divided between the

eastern and western parts of the coimtry; 27

plants with a productive capacity of 2,080,000 tons

of nitrogen are situated east of the Mississippi

River and 32 with a capacity of 2,166,000 tons lie

west of the river. All but two of the plants are

privately operated. The plant at Wilson Dam,

Ala., is operated by the Government. The Morgantown, W. Va., plant is Government-owned and

had been leased and operated by a private company until July 15, 1959, when the lessee turned

it back to the Government.
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION 13

TABLE 13.—Domestic anhydrous ammonia manuiacUiring plants existing or under construction, January 1,1960

Company and location

Allied Chemical Corp., Hopewell, Va

Allied Chemical Corp., Omaha, Neljr

Allied Chemical Corp., South Point, Ohio

American Cynamid Co., New Orleans, La

Apache Powder Co., Benson, Ariz

Armour Agricultural Chemical Co., Crystal City, Mo...

Atlantic Refining Co., Philadelphia, Pa

California Ammonia Co., Lathrop, Calif

Calumet .Vitrogen Products Co., Hammond, Ind

Coastal Chemical Co., Pascagoula, Miss

Collier Carbon and Chemical Corp., Brea, Calif

Columbia-Southern Chemical Corp., Xatrium, \V. Va..

Commercial Solvents Corp., Steidington, La

Cooperative Farm Chemicals Assoc, Lawrence, Kans__.

Deere and Co., Pryor, Okla

Dow Chemical Co., Freeport, Tex

Dow Chemical Co., Midland, Mich

Dow Chemical Co., Pittsburg, Calif

E. L du Pont de Xemours & Co., Belle, W. Va

E. I. du Pont de Xemours & Co.. Xlagara Falls, X.Y._.

E. I. du Pont de X'emours & Co., Oibl)Sto\vn, X.J

Escambia Chemical Corp., Pensacola, Fla

Food Machinery i Chemical Corp., Charleston, W. Va

V.'. R. Grace and Co., Memphis, Tenn

Hercules Powder Co., Louisiana, Mo

Hercules Powder Co., Hercules, Calif

Hooker Electrochemical Co., Tacoma, Wash

Ketona Chemical Corp., Ketona, Ala

Mississippi Chemical Corp., Yazoo City, Miss

Monsanto Chemical Co., El Dorado, Ark

Monsanto Chemical Co., Luling, La.

Estimated

annual

capacity

1,000

ions

short

N'

329

02

263

44

8

58

29

2 30

86

2 4.5

74

27

11.5

52

54

74

20

6

191

8

2 50

58

18

72

33

41

19

39

80

173

120

Company and location

32. X'orthern Chemical Industries Inc., Searsport, Maine

33. 01in-.\lathicson Cliemica] Corp., Lake Charles, La

34. Olin-.Mathicson Chemical Corp., Xiagara Falls, X.Y

35. Pennsylvania Salt -Marmfacturing Co., Portland, Oree._.

36. Pennsylvania Salt .Manufacturing Co., Wyandotte, Mich

37. Petroleum Chemicals, Inc., Lake Charles, La _

38. Phillips Chemical Co., Etter, Tex

39. Phillips Chemical Co., Port Adams, Tex

40. Phillips Pacific Chemical Co., Kennewick, Wash

41. Rohm & Haas, Deer Park, Tex

42. St. Paul Ammonia Products, Inc., Pine Bend, .Minn. ._.

43. Shell Chemical Co., Pittsburg, Calif

44. Shell Chemical Co., Ventura, Calif

45. Smith-Douglas Co., Inc., Pasadena, Tex

46. Sohio Chemical Co., I/ima, Ohio

47. Southern Xitrogen Co., Inc., Savannah, Ga

48. Southwest Agrochemical Corp., Chandler, Ariz

49. Spencer Chemical Co., \^^ Henderson, Ky

50. Spencer Chemical Co., Pittsburg, Kans

51. Spencer Chemical Co., Vicksburg,-Miss

.52. Standard Oil Co. of California, Richmond, Calif

53. Sun Oil Co., Marcus Hook, Pa

.54. Tennessee Valley Authority, Wilson Dam, Ala

55. Texaco Inc., Lockport, 111

56. U.S. Government, .Morgantown, W. Va

67. U.S. Industrial Chemicals Co., Tuscola, 111

58. U.S. Steel Corp., Geneva, Utah

•59. Valley Xitrogen Producers, Helm, Calif

Total

Estimated

annual

capacity

1,000

tons

short

N'

36

90

6

12

26

82

158

158

60

40

58

97

66

33

86

72

! 17

61

144

58

86

90

74

52

164

41

58

44

4,246

1 Unless otherwise noted, calculated from data in Chemical Statistics

Handbook ílSíi.

- Estimated.

%

FIGURE 1.—Anhydrous ammonia manufacturing plants, .lanuary 1, 1^60.
14 AGRICULTURE HANDBOOK 19 8, U.S. DEPARTMENT OF AGRICULTURE

Aqua ammonia is produced by mixing anhydrous ammonia with Avater or as a byproduct of

coke phxnts. The anhydrous ammonia, in many

cases, is sliipped out to large-scale conversion

plants for quantity production of aqua ammonia

or to smaller plants where aqua ammonia is prepared for local use. As it is unloaded from tank

cars the anhydrous ammonia can be piped directly through a converter into aqua ammonia

storage (188), thereby eliminating the need for

high-pressure storage facilities. Aqua ammonia

also is produced at some ammonia-synthesis

plants.

The other pressure liquids are prepared by

adding anliydrous ammonia to aqueous solutions

of the salts. The ammonium nitrate is formed by

neutralizing nitric acid with ammonia (162, pp.

Jpi2-Ji.l3) and the urea is manufactured l3y reacting carbon dioxide with ammonia in the liquid

phase under greatly elevated pressure and temperature {6Jf, 189). The aqueous solutions of the

salts are blended with anhydrous ammonia under

pressure and then passed through coolers to storage. Pressure storage containers are used to prevent loss of ammonia. The carbon dioxide

contents of solutions LP-13, MP-8, -10 and -12

are due to the use of urea solutions from which dissolved CO2 had not been completely removed.

The nonpressure liquids are aqueous solutions

of solid nitrogen materials. They may be solutions withdrawn at some stage during the production of the material, diluted or blended

mixtures of such solutions, or the solid materials

dissolved in water. Seven of the listed solutions

(table 5) are fundamentally dilutions of the 83

percent ammoniima nitrate solution withdrawn

from the process following neutralization of nitric

acid with anmionia.

SAFETY REGULATIONS AND PRECAUTIONS

Safety regulations are based primarily on the

use of anhydrous ammonia. Many of the regulations are applicable to the pressure solutions, but

none of them apply to the nonpressure solutions.

No specific recommendations have been made on

the basis of the salts in the solutions, but applicable precautions, based on the inherent hazards

of ammonium nitrate as described by Davis (77),

should be observed.

Regulations and suggestions for the safe handling of liquid nitrogen fertilizers have been formulated by the Interstate Cominerce Commission

(194-), the Compressed Gas Association, Inc. (62) y

the National Safety Council (UfS), the Agricultural Ammonia Institute (15, 50), and many

State and local authorities. A list of the State

agencies having jurisdiction over the storage and

handling of liquid nitrogen fertilizers is given in

the appendix. Many nitrogen fertilizer manufacturers have published brochures containing suggestions for handling the liquids (61, 76,1^7,148,

149,163,176,177,180,186).

The Interstate Commerce Commission classifies

anhydrous ammonia as a nonflanxmable compressed gas. It must be packaged in ICC specification containers ; all ICC Regulations regarding

loading, handling, and labeling must be followed.

Each container (including tank cars) should

carry an identifying label or stencil. Tank cars

must be stenciled to show ICC class No. 105A-300

and must carry the ICC "Dangerous" placard

when loaded. Each cylinder must carry the ICC

green label of nonflammable compressed gas, the

name of the owner, serial number, test date, and

ICC specification number. Also the Manufacturing Chemists' Association (13S) describes a warning label that is recommended for use on each

container in addition to any labels required by

statutes, regulations, or ordinances. Although

the ICC Regulations apply specifically to interstate movement of ammonia, many States have

adopted them for intrastate shipments as well.

The Interstate Commerce Conxmission does not

regulate shijiments of any of the other liquid

forms of fertilizer nitrogen. Aqua anunonia,

however, is usually shipped in ICC specification

containers, and it is recommended that the containers carry a warning label (131). The tank

cars usually comply with ICC specification 103 or

103A and steel drums are labeled ICC specification 5 or 5A.

Tanks for storing anhydrous and aqua ammonia should be fabricated in accordance with

the American Society of Mechanical Engineers

code for mifired pressure vessels (19). Underground containers for anhydrous ammonia should

have a minimum design working pressure of 250

pounds per square inch and aboveground containers should be designed for 265 pounds per

square inch working pressure.

State and local ordinances generally specify

that anhydrous ammonia storage tanks shall not

be located in densely populated areas or within

certain fixed distances—50 to 200 feet—from a

dwelling, an important building, railroad, or

public highway. Buildings, in which tanks are

located, must have openings at the top for natural

ventilation. A tank located outside a building

should be shaded or painted a light color to reduce heat absorption from the sun. Howell (98)

states that the pressure exerted by anhydrous

ammonia in a 110-gallon tank painted white was

approximately 40 pounds lower throughout the

summer than in a similar tank painted aluminum.

Tucker and Dyer (192) show that the maximum

pressure exerted by ammonia in tanks painted

white was approximately 90 pounds lower than in

rusted tanks at air temperatures of 104° to 108° F.
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION 15

Some States require that the words "DANGEE—

AMMONIA" be printed on both sides and ends of

the tank in red letters at least 6 inches high.

Aqua ammonia and the other pressure solution

containers siiould be designed for a working pressure of not less than the vapor pressure of the

contained solution at 115° F. The tanks for

aqua ammonia should have a minimum working

pressure of 100 pounds per square inch. Tanks

for the pressure and nonpressure solutions, when

pressure is used to transfer the solution, should

be designed for a 30- to 35-pound-per-square-inch

working pressure, in accordance with the code for

unfired pressure vessels. The nonpressure solutions can be stored in nonpressure tanks or open

containers when the solution is transferred by

pumps or gravity.

Valves {70) and accessory equipment for tanks

must be approved for the liquid to be handled.

Tanks should be equipped with spring-loaded or

equivalent type safety relief valves, with direct

communication to the vapor space of the container. The valves should be vented to the open

air away from the container. Loading and unloading operations should be protected by excessflow and backflow check valves. Fittings for

truck and trailer tanks should be installed in the

rear end of the container and should be protected

by a heavy permanent fixture. The container

should be equipped with baffle plates to eliminate

surging of the liquid.

Liquid nitrogen fertilizer equipment, tanks,

and lines should be thorouglily washed and purged

before repairing {85). Flammable air-aimnonia

mixtures may be formed and ignited during welding or cutting. The high temperatures of these

operations decompose any residual ammonium

nitrate. The reaction is exothermic and potentially explosive.

Spilled aimnonimn nitrate and sodium nitrate

solutions should be cleaned up immediately, as the

salts, like nitrates in general, present a fire hazard.

Spontaneous combustion may occur when organic

material containing nitrates comes in contact with

hot surfaces such as steam pipes. Wooden floors

impregnated with ammonium nitrate will ignite

readily when exposed to heat, and the oxygen

supplied by the nitrate will support combustion.

MARKETING AND DISTRIBUTION

The marketing of liquid nitrogen fertilizers

does not follow a fixed pattern. Producers may

sell to fertilizer manufacturers, bulk distributors,

a group of consumers, or to the ultimate consumer. The bulk distributor sells to the consumer. The liquids may be sold to the farmer on

a delivered-to-the-farm or applied-to-the-soil

basis.

Anhydrous ammonia generally moves from the

primary pi'oducer to fertilizer manufacturers or

bulk distribution facilities. The manufacturers

use it in the production of mixed fertilizers and

seldom sell ammonia for direct application. Bulk

distribution centers provide supplementary offseason storage for the producer and enable the

distributor to have a supply available when

needed. Distribution facilities are financed privately, by primary producers, or by cooperative

associations. Those financed by the primary producers are operated by the company or leased to

independent operators. Leases are so arranged

that the producer is assured of ammonia outlets

and the distributor has the assurance of a

supplier.

Some ammonia is moved from the producing

plant to the field in company-owned equipment

and applied to the soil by company personnel

(183). The ammonia is sold on an applied basis

rather than on an f.o.b. plant basis. Essentially,

all the ammonia sold by one producer for direct

application is marketed as aqua ammonia {4)-

Aqua ammonia may be made at the ammoniaproduction plant or from anhydrous ammonia

shipped to local conversion stations. Otherwise,

68ft»70 o—61 3

the pattern of its marketing and distribution is

about the same as that of anhydrous ammonia.

The movement of the other liquid nitrogen materials follows much the same pattern as that of

anhydrous ammonia except for the fact that established fertilizer mixing plants often replace

other distribution facilities or are an intermediary between the producer and distributor. As

the use of liquid nitrogen fertilizers develops,

there is a tendency for a greater percentage of

the liquids to go directly from the producer to

bulk distributors.

Probably any of these liquids can be purchased

from a primary producer by a farmer or group

of farmers having storage facilities for a carload

or more of the product. Such purchases can be

made during the slack season and at off-season

prices. The privately owned storage tank is located in some cases at a bulk distribution plant

rather than on the farm. The distributor charges

a small fee for maintaining the equipment, for

assuring the farmer of an adequate supply of

liquid fertilizer when needed, and for transferring the liquid to the farmer's equipment.

These liquids are applied to the soil by custom

applicators or by the farmer. According to Lowe

{1^2) custom application has been used to develop new market areas. This method is still one

of the principal means of applying liquid nitrogen fertilizer on farms, but Smith {174) states

that there is a distinct trend an^^ng farmers

having more than 200 acres of cropland to purchase or rent an applicator.
16 AGRICULTURE HANDBOOK 19 8, U.S. DEPARTMENT OF AGRICULTURE

The operator of a custom application service

provides over-the-road transport and field tanks

and application equipment. He contracts with

the farmer to fertilize his fields at the desired

time and rate of application. Bulk distributors

often supply tlie custom service. The cost of this

service depends on the method of application—

whether the liquid is applied on the soil, below

the surface of the soil, or in irrigation water—

and on the texture of the soil. The cost of application in some cases is included in the price of the

nitrogen.

In the trend away from custom application, a

farmer or a group of fai-mers may purchase or

rent an applicator. The distributor then may

service the equipment and supply the fertilizer to

farm-storage facilities or provide it in small tanks

that are left on the farm until empty. The

empty tanks are picked up for servicing and refilling by the bulk distributor. The farmer saves

some cash expenditures and is able to apply his

fertilizer at the most advantageous time. The

distributor avoids the expense of a large inventory of applicators for limited seasonal use.

There are no Federal regulations covering the

sale of fertilizer, but there are State fertilizer

laws. Connor {63) summarizes the scope and the

fee and labeling provisions of the fertilizer control statutes of each State. The statutes are enforced by State fertilizer control officials and,

in general, govern labeling and tax and registration fees and prescribe plant nutrient standards

for commercial fertilizers. For complete information on laws relating to the fertilizer industry,

the manufacturer should consult the latest statutes

of the several States in his marketing area.

STORAGE AND HANDLING

Storage

Anhydrous ammonia

points is provided usually by hortonspheres (fif^

2), with capacities ranging up to several hundred

storage at producing

FIGURE 2.—Hortonspheres for the bulk storage of anhydrous ammonia. Courtesy of Lion Oil Co.

thousand gallons. Hortonspheres are used by a

few bulk distributors. High-pressure cylinclers

and horizontal tanks (figs. 3 and 4) are also used

for storage by some manufacturers and by most

bulk distributors. Some anliydrous ammonia is

stored by the producers in the form of aqua ammonia and regenerated for shipment.

The hortonspheres are large spherical tanks

with moderately low working-pressure designs.

They are provided with a refrigeration unit to

guard against excessive pressure. As the ammonia vaporizes within the sphere, a compressor

draws off the vapor, compresses it into a liquid,

and returns it to the sphere. Insulated spheres

are used in some cases.

Aqua ammonia is generally stored by the producers and bulk distributors in low-pressure,

vertical tanks. Small quantities can be kept in

drums and carboys.

Storage at producing plants for nitrogen solutions containing ammonia, except aqua ammonia,

is almost negligible. The solutions are blended

and loaded directly into tank cars for shipment.

Where storage is provided, several low-pressure

or high-pressure horizontal tanks—depending on

the vapor pressure of the solution—are favored

because of the number of different solutions produced. The tanks enable the producer to stock

different solutions and to fill orders for various

types of solution inunediately.

Permanent storage facilities for nitrogen solutions at bulk distribution centers consist of either

30,000-gallon pressure tanks or batteries of tanks

with capacities as small as 6,000 gallons. The

bulk distributor will also have portable tanks

with capacities of 500 to 1,000 gallons. These are

used to carry the solutions out to the field where

they are left until emptied by the farmers. The

portable tanks can be used for storage during the

off season either on the farm or at the distribution

center. Storage at bulk distribution centers is

sometimes supplemented by farm storage. The

most popular size of farm storage tank has a

capacity of 1,000 gallons {l.!f7).

The nonpressure nitrogen solutions can be stored

in vertical tanks. Some consideration has been

given to sunken concrete tanks or cisterns for

storing nonpressure solutions, but such storage is

not commonly used.

The minimum storage capacity at a bulk plant

should be about 12,000 gallons or large enough

to receive a tank-car shipment before the storage

facilities are completely empty. Optimmn capacity should be adequate for storing a good proportion of the material that will be used for spring

application. The storage required will depend on

the length of the fertilizer season and the volume
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION 17

FIGURE 3.—High-pressure storage and transfer tanks for anhydrous ammonia at a large bulli distribution plant.

Courtesy of Mid-South Chemical Corp.

FIGURE 4.—Stationary 30,000-gallon tanlis for storing anhydrous ammonia.
18 AGRICULTURE HANDBOOK 19 8, U.S. DEPARTMENT OF AGRICULTURE

of business handled by the comj^any. Local

storage is a prerequisite, since the producers do

not have sufficient storage capacity nor are the

railroads equipped to take care of the peak load

in the spring. Also, during periods of nitrogen

shortages, sales contracts have required that deliveries liad to be accepted in equal ¡periodic shipments over the year. Storage facilities can be

filled during the ofl' season when pidces may be

lower than during the fertilizer season.

Transportation

Anhydrous ammonia is transported in bulk and

in cylinders. The major part moves out of producing plants in high-pressure, insulated tank

cars with capacities of 10,000 gallons (i^^, 176^

177). Deliveries are also made in 6,800 gallon

high-pressure tank trucks {177). Smaller trucks

are used for movements between the bulk distributor and farmer. The essential equipment and

proper use of trucks for transi^orting ammonia

are discussed in some detail by Tucker {191).

Some producers of anhydrous ammonia ship a

part of their output by water. The first bulk shipment by water was made in 1954 {3) in an oceangoing barge, which is shown in figure 5. The

vessel has a capacity of 1,680 tons and the ammonia is carried in 7 uiider-deck and 2 on-deck

tanks (7). Welded anhydrous ammonia barges

(fig. 6) are also used. They are a hopper-type

barge, in which a battery of six pressure tanks

has a capacity of 400,000 gallons of anhydrous

ammonia (i^, 72).

Anhydrous ammonia used in irrigation water is

trucked to the field in cylinders containing 25 to

150 pounds of apimonia. The cylinders are unloaded on the banks of the irrigation ditches and

are ready for use w^ien the water is turned in.

Producers normally ship aqua ammonia in tank

cars with capacities of 6,000 to 10,000 gallons

{148, llt9, 176, 177). Movement from bulk distribution centers and ammonia conversion plants is

by tank truck. Preference is shown, generally, for

tanks with capacities of 1,000 gallons for over-theroad hauls, but in some cases tanks with 3 times

this capacity are used. Water-borne tankers were

.-« -5=>''rf^"« "T'-f.T-i- ^-»-»-T ^'''"

FIGURE 5.—Ocean-going barge for transporting anhydrous

ammonia. Courtesy of Shell Chemical Corp.

riGUBE 6.—Welded barge for transporting anhydrous

amomnia. Courtesy of Ingalls Shipbuilding Corp.

first used in 1953 {2) for bulk shipments of aqua

ammonia from California to Hawaii. The capacities of the tankers ranged from 5,000 to 42,000

gallons.

Producers commonly ship the nitrogen solutions

containing dissolved salts in 10,000-gallon insulated tank cars. Some shipments are made in

transport trucks carrying 1,000 to 3,000 gallons of

solution. Low-pressure equipment is used except

in the case of solutions with elevated vapor pressures. Such solutions require high-pressure tanks.

Mobile supply trucks of 500- to 1,000-gallon capacity are used to move solutions from dealer's

storage plants to the field.

Transfer

Transfer of anhydrous ammonia and the pressure solutions between containers should be made

in a closed system to prevent loss of nitrogen.

Many commercial brochures {61, 76, lJi.7, IJjß, 14-9,

153, ISO, 185) give layouts and descriptions of

transfer systems for the various types of liquid

nitrogen fertilizers.

Anhydrous ammonia is transferred at bulk

plants by means of compressors, vaporizers, or

under its own vapor pressure. Compressors are

used to force the vapor of the receiver into the

vapor space of the supply tank. The pressure differential forces the liquid ammonia into the receiver. The same result is achieved, with a

vaporizer that builds up the pressure diiïerential

through the application of heat to the liquid.

The normal vapor pressure of the liquid is also

used to transfer anhydrous ammonia.
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION 19

Anhydrous ammonia is transferred in the field

by connecting the tractor and delivery tanks with

vapor-return and liquid delivery hnes. Ihe

valves are opened on these lines and the pressure

differential between the tanks is adjusted to approximately 10 pounds per square inch by regulating the opening in the vapor valve of the

tractor tank. When the tractor tank is 85 to 90

percent full, a white fume escapes from the vapor

line. Loading is then complete and the valves are

closed.

Bulk transfer of nitrogen solutions is made by

gravity, solution pumps, or compressed air.

Gravity transfer is made through bottom outlet

valves "that should be screened to prevent clogging

of the tank outlet. Solution pumps are generally

used for moving nonpressure solutions, but they

can also be used with negligible losses of nitrogen

for low-pressure solutions. Air pressure is the

most popular means of moving nitrogen solutions

despite the hazard of forming explosive airammonia mixtures.

The nitrogen solutions are transferred from

transport or storage tanks to applicator tanks by

hand pumi?, power takeoff pumps, and gravitj^ or

by means of the vapor pressure of the liquid. The

vent valve of the applicator tank is oj^en during

filling and the appearance of a white fume at the

vent indicates the tank is 85 to 90 percent full.

APPLICATION METHODS AND EQUIPMENT

Liquid nitrogen fertilizers are applied to the soil

by subsurface and surface application and

through sprinkler and surface irrigation. All

these methods can be used for applying the nonpressure solutions. Ammonia and the pressure

solutions generally are applied below the surface

of the soil or through surface irrigation.

Subsurface applications are most effective on

soils in good tilth. Liquids are applied in this

manner as a preplant application and as a source

of supplemental nitrogen for row crops.

Surface applications of nonpressure solutions

can be made on stony soils with a minimmn loss

of nitrogen. Nitrogen can be applied to sod and

close-growing crops by this method. Spray applications are particularly adapted to sandy soils

and can be used for most major crops. This

method of application is used also to feed plants

through their leaves. Surface irrigation is an

effective means of applying liquid nitrogen fertilizers to row crops, including truck crops, tree

fruits, small fruits, and vineyards, growing on

loams and clay loams.

Subsurface Application

Subsurface application is the principal method

of applying the liquid nitrogen fertilizers characterized by a positive vapor pressure. Anhydrous

ammonia and the pressure solutions are injected

4 to 8 inches below the surface of the soil to the

sides of narrow furrows. The furrows are closed

immediately after the application to miniiidze

nitrogen losses by sealing in the gaseous ammonia.

Nonpressure solutions can be applied in the same

manner.

The basic application equipment consists of a

tank, metering device, distributor manifold, hoses,

and applicators. There are nmnerous types of

equipment, and some of these have been described

by Barr {32) and Andrews {25, 27). The three

major assemblies used for applying anhydrous

ammonia to the soil are (1) tractor momited, (2)

a trailino" unit, and (3) a semimounted miit supported by both tractor and trailing miit. The

miits (fig. 7) consist essentially of a tank, metering mechanism, and soil tools. The soil openers

are usually mounted on a cultivating-type tool

bar with special soil-knife applicators. Figure 8

is a schematic drawing of this type of equipment,

and the details of the applicator blade are shown

in figure 9.

The liquid is forced from the regulator into a

compact manifold fitted with orifices to apportion the liquid to the applicators. The applicator

blades are steel and are usually curved forward

so the toe of the blade is ahead of the shank. This

facilities the shedding of trash. The blades are

either heat-treated or hard-surfaced to resist

abrasion. Slip-on applicator boots are often used

to prolong the life of the applicator knives or

blades. On the back of each applicator is welded

a small metal pipe through which the liquid

passes mto the soil. Small gas exit ports are located usually on the side of the metal pipes and

close to the bottom of the cutting blade. The

BN-12042

FIGURE 7.—Anhydrous ammonia applicator mounted on

a farm tracLor.
20 AGRICULTURE HANDBOOK 198, U.S. DEPARTMENT OF AGRICULTURE

FIGURE 8.—Anhydrous ammonia applicator.

ports should not be so low that the wearing off of

the knives would affect the discharge opening.

The knives are attached to a tool bar with a shear

pin or spring arm to prevent breakage if a resistant root or rock is encountered. Pasture applicators are often equipped with coulters ahead

of the applicator knives to assist in penetration,

to hold disturbance and dragging to a minimum,

and to prevent clogging of the equipment. A

press wheel or slide is usually located behind the

applicators to close the soil furrow or cut, thereby

sealing in the aimnonia.

The accurate metering of anhydrous ammonia

requires it to be measured either as a liquid or as

a gas (32). Erroneous measurements will occur

if liquid-gas mixtures are metered. The practice

is to measure ammonia as a liquid, and the devices

currently used (fig. 10) fall into two systems—

pressure and pump. Equipment should be calibrated with the same liquid, same size of hose and

manifold, and same type of applicator knife or

blade that will be used in the field. Calibration

data and directions for any metering device are

normally provided by the manufacturer.

Needle Valve

and Orifice

System

Pressure

Control Valve

c Tank

Adjustable

Pressure

Regulator

Pressure Regulator

Orifice

System C

^

-Oriti(

/ ^To Applicator

Feet

Distributor

Manifold

Blade Material:

Forged Steel, Heat

Treated to Resist

Abrasion

Connecting

Pipe

Fertilizer Injec

in Soil Throug

on Each Side o

BN-12045

FiGUEE 9.—Detail of applicator blade for anhydrous

ammonia.

Crankshaft

Metering

Piston

Pump

Heat ExchangerBN-12046

FiGUEE 10.—Common methods of metering anhydrous

ammonia.

The amount of liquid delivered by the pressure

systems per linear unit of travel of the distributor

is dependent on the gage pressure of the contained

liquid, orifice size, static line pressure, and speed

of the applicator rig. The rate of application for

a given tractor speed is determined by the size of

the orifice and the liquid pressure exerted. Barr

(Sß) shows examples of these relations for one

type of automatic control valve on implements of

various widths. A uniform pressure and a constant speed of travel are necessary to maintain a

uniform rate of application.

Methods of controlling the pressure are shown

in the upper two drawings of figure 10. Pressure

is controlled in the needle valve-orifice system by

manually adjusting the valve as other factors

vary. The automatic differential pressure regulator in the other system can be set in the morning
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION 21

to deliver a given quantity of liquid per hour and

will not ha^-e to be reset during the day.

The pump system for metez4ng anliydrous ammonia consists of a variable stroke displacement

pump and heat exchanger, as shown in the lower

drawing of figure 10. The metering pump is

driven from the rear axle of the tractor or from

one of the wheels of a trailer applicator. The

length of the stroke controls the quantity of liquid

entering the distributor manifold. After a desired

rate of application has been calibrated for a

ground-driven displacement pump, the rate per

acre is fairly constant, regardless of the speed or

change of speed the rig may experience while in

operation. The flow of liquid stops when the rig

stops. The heat exchanger cools the outgoing ammonia and prevents it from vaporizing in the

pmnp. The principal disadvantages of grounddriven metering are the relatively high initial cost

and the expense of annual servicing, which is an

essential requirement of this type of equipment.

The principles governing the application of anhydrous ammonia into the soil are also applicable

to the application of both the low- and medimnpressure solutions. The solutions are forced into

the distributor manifold and through the applicators by air compressors or solution pumps driven

by a poAver takeoff or geared to the drive wheel

of the tractor (fig. 11). A pressure-regulating

valve between the compressor and the solution

tank maintains a constant pressure in the solution

tank, regardless of the quantity of solution and

changes of temperature in the system. This

method provides a uniform discharge rate. It has

the disadvantage that air pumped into a tank

containing ammonia gas may form an explosive

air-ammonia mixture, although the hazard in-

\-oh'ed is less than that connected with the gas

chamber in the fuel tank of the tractor.

Pump equipment for the low- and mediumpressure solutions is the most A'aried and generally

used of all types (i^^). A wide variety of pumps

works on the tractor power takeoff'—centrifugal,

diaphragm, gear, piston, roller, and others. Most

models allow liquid discharge when the pump

stojDS and require a manually operated valve to

shut off the flow. The gear pump is positive in

its deliver}' and is durable when properly constructed. Diaphragm pimips are inexpensive, positive in action, and corrosion-proof. However, a

certain amomit of pulsation seems almost inevitable Avitli this type of piunp.

These pmnps may give uniform discharge rates,

but uniform application rates are not attained unless an unvaried ground speed is maintained in the

field. Their successful adaptation to grounddriven equipment has been difficult.

The variable-stroke piston pmnp used for the

application of anhj^drous ammonia can be used for

the application of other pressure solutions. The

FiGUEE 11.—Application of aqua ammonia to the soil.
22 AGRICULTURE HANDBOOK 19 8, U.S. DEPARTMENT OF AGRICULTURE

rate of application of this pump is uniform, regardless of throttle or gear changes of the prime

mover of the field equipment, and its use is recommended for small fields or irregular terrains. Its

use, however, is limited by its higher initial cost

and greater corrosion hazards.

Surface Application

Liquid nitrogen fertilizere are applied to the

soil in surface irrigation water and by various

liquid-dispensing systems, including spray and

sjjrinkler systems. Any of the liquids can be applied in flood and ditch irrigation water, whereas

the nonpressure solutions are customarily the only

ones applied in sprinkler irrigation water. Dilute

aqua ammonia has been applied successfully by

spray irrigation {167), and diluted low-pressure

solutions have been dribbled onto the surface of

the soil or into open furrows. Dilute solutions are

also sprayed on the foliage of plants for the purpose of having the nitrogen absorbed through the

leaves. If the solutions are too concentrated, they

will bum the foliage unless washed off with fresh

water.

Care must be taken in applying pressure liquids

in irrigation water, as excessive quantities of nitrogen may be fomid near the water inlet on soils

with high infiltration rates. The ammonia of the

pressure solutions also causes objectionable calcium carbonate deposits on the pipes and valves

of irrigation systems using hard water (109,164.) •

The deposits can be prevented by adding sodium

hexametaphosphate to the irrigation water ahead

of the point where the ammonia is introduced.

Jordan (109) states that 1% ounces of dry hexametaphosphate will inhibit calcium carbonate deposition in 100 gallons of water of 1 grain hardness

(17.1 p.p.m. of dissolved calcimn).

Anhydrous ammonia is metered from cylinders

into the irrigation water under its own pressure.

The cylinders are laid horizontally on the ground

adjacent to the head ditch or standpipe (fig. 12).

The ammonia from a single cylinder or a manifold

connecting two or three cylinders is measured into

the irrigation water through a hose connected to a

metering orifice. The rate of flow through the

orifice is controlled by the orifice size and the ammonia pressure, which is regulated, in turn, by a

control valve.

The pressure and nonpressure solutions can be

added to surface irrigation water by gravity. The

solutions are carried out to the fields in tanks

equipped with extensible legs. The tanks are set

up adjacent to the irrigation water, as shown in

figure 13. A manually operated control valve

regulates the flow of solution through a rubber

hose into the water. Atmospheric pressure is

maintained in the tank by venting it to the air.

Nitrogen losses through the vent are negligible,

even when pressure solutions are applied in this

manner.

FIGURE 12,—Application of anhydrous ammonia to irrigation water in California.

BN-12039

FiGUKE 13.—Gravity application of nonpressure liquid

nitrogen fertilizers to irrigation water.

Nonpressure nitrogen solutions are added to the

water of sprinkler systems by two methods—

gravity and differential pressure {H7). In the

gravity method a valve inlet is installed on the

suction side of the water pump, and after irrigation begins the valve is opened sufficiently for the

fertilizer solution to be drawn into the system.

The differential pressure method requires a restricting orifice in the water pipeline. Valves are

tapped into the pipe on each side of the orifice.

The valve on the entrance side of the orifice is connected to a vent valve on the liquid fertilizer container, and the valve on the exit side of the orifice

is connected to the discharge valve of the container. Water passing through the orifice builds

up a pressure differential that draws the solution

out of the tank. The desired w'ithdrawal rate is

obtained by adjusting both valves.

Nonpressure solutions are applied directly to the

soil through spray booms. The solutions can be

fed to the boom by many of the metering systems

used in subsurface application and by gravity.

A simple, open-gravity system will have a relatively uniform liquid pressure at the discharge

nozzle or orifice if the discharge opening of the

tank is at least 4 feet above the orifice. Gravity

kits have four or more orifice sizes for different
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION 23

discharge rates {5). After an orifice has been

selected, the final adjustment of the rate o± application is made by varying the tractor speed

with the throttle. A float chamber between the

supply tank and the discharge orifices may be

used to maintain a constant hydraulic head independent of the amount of liquid in the tank.

The principle is similar to that of the float chamber in a cream separator.

Futral and others {88) describe a closed-gravity

system that eliminates fluctuations in the rate of

liquid flow caused by changes in the height of

liquid in the container. A representative layout

consists of a closed container with an air-intake

pipe open to the air at the top of the container

and extending down to a point near the bottom.

The liquid is drawn from the bottom of the tank

through a cutoff valve in line with a needle valve

or orifice that regulates the rate of flow. The

hydrostatic pressure at the needle valve is the

pressure exerted by the height of liquid from the

orifice to the bottom of the intake pipe.

In the early 1940's, a metering hose pump was

adapted to the application of nonpressure liquids

at the University of Tennessee {170). Pump

modifications worked out by ARS research engineers in 1953 and 1954 led to commercial production of the pump for farm use (PÖ, 91). The

pump (figs. 14 and 15) consists essentially of a

4-bar rotating reel with a series of flexible hoses

mounted on the reel in the form of an inverted

"U". Contact of the bars with the hose closes the

tubes, and the open tubes between the contact

points form pockets that contain the liquid. As

the reel rotates, the liquid in the pockets is forced

forward in each hose line. The rate of application is governed by the reel speed in relation to

ground travel. As the machine slows or stops,

the flow of liquid slows or stops automatically.

There is no contact between the solution and the

rotating mechanism. This pump can deliver

liquid through 1 to 12 outlet hoses.

Any rate of application of the metering hose

pump is uniform, regardless of throttle or gear

Í^Íj¿;íírf;7í?VÍ

FiöUKE 14.—Assembly, showing metering hiose pump and

wooden boom for broadcasting nonpressure solutions.

FiGUEE 15.—Closeup of metering hose pump.

changes of the primary mover of the field equipment. The pump can also be used for subsurface

applications.

Nitrogen Losses During Application

Nitrogen losses during application of liquid

nitrogen fertilizers are due primarily to the ammonia vapor pressure of the liquids. The nitrogen

salts in the solutions exert no vapor pressure and

are not subject to loss. Ammonia losses can be

minimized by the use of proper application equipment and good management practices. Dilution

of the pressure solutions before application will

aid in reducing nitrogen losses.

Ammonia gas may escape from the pressure

liquids along the sides of the soil openers or from

the furrows before they are closed. Additional

losses may occur when the pressure liquids are applied to soils with low infiltration rates. Some

evaporation of amn^onia will occur from irrigation water to which pressure liquids are being

added.

Losses of ammonia from irrigation water vary

greatly. Eosenstein {161) stated that loss by

evaporation is negligibly small at a concentration

of 109 p.p.m. of ammonia in water. Chapman

{59) calculated from experimental data that

losses of ammonia from water containing 50

p.p.m. of ammonia-nitrogen would be less than

10 to 12 percent under most conditions. Losses

may exceed 26 percent under conditions of high

water temperature and very low soil permeability.

Babcock {30) found that a solution containing

107 p.p.m. nitrogen, as ammonia, lost 80.2 percent of the nitrogen in traversing a distance of

540 feet in 30 minutes through an open concrete

flume. A study by Sokoloff {179) indicated that

losses of ammonia from irrigation water can be

minimized by (1) irrigating on cool, humid, quiet

days; (2) maintaining a concentration of not over

110 p.p.m. of ammonia; and (3) keeping the exposed surface of flowing water to a minimum by
24 AGRICULTURE HANDBOOK 19 8, U.S. DEPARTMENT OF AGRICULTURE

reducing the tui-bulence of the water and by using

narrow, deep ditches.

Rayburn [157) considered nitrogen losses negligible when water containing 30 to 40 p.p.m. of

ammonia was applied to the soil through a sprinkler system. Henderson, Bianchi, and Doñeen

[97) determined the ammonia losses between the

time aqua ammonia left a revolving sprinkler

head and was caught in a receptacle. The losses

from alkaline irrigation water solutions containing 50 and 100 p.p.m. of ammonia were 45 and 55

percent, I'espectively. Similar tests in alkaline

irrigation water were made with solutions containing 25, 50, 100, and 300 p.p.m. of ammonia in

the form of either ammonium nitrate, ammonium

phosphate, or ammonium sulfate. Losses at the

various concentrations were 10, 6, 4, and 0.5 percent, respectively, for ammonium nitrate and

animonimn phosphate and 25, 12, 8, and 3 percent

for ammonium sulfate. Anunonia losses decreased with decreasing alkalinity of the fertilizer-irrigation water solution and were negligible

for neutral or acid solutions.

The work of Jackson, Alban, and Wolfe {103)

also shows that appreciable amounts of nitrogen

are lost as aqua ammonia travels from the sprinkler head to the soil. Samples of solution were

caught in basins set 10, 20, and 30 feet from the

sprinkler head and the ammonia losses determined. The results, given in table 14, show that

the greatest loss takes place near the sprinkler

heacl and decreases with distance. Presumably,

loss near the sprinkler head can be associated with

droplet size, since a larger proportion of small

drops fall near the sprinkler.

TABLE 14.—Ammonia losses during sprinkler application '

Water source and concentration of

ammonia (NHa) applied (pounds

Ammonia loss at following distances

from sprinkler head

per acre-inch)

10 feet 20 feet 30 feet

Ponded river water, 70° F.:

9 0

Percent

33.3

41.9

48.4

60.2

26.4

36.9

50.4

47.4

Percent

25.7

40.6

47.4

67.6

24.0

30.6

44.7

414

Percent

20 0

n.o 319

19.5 43.4

25.5 45.9

Well water, 52° F.:

11.5 - 21.7

18.5 26.1

25.6 35.4

38.5.. . . - . 36.0

1 Data from Jackson, Alban, and WoKe (103).

LIQUID NITROGEN FERTILIZERS IN THE SOIL

Many agronomic factors governing the use of

solid nitrogen materials also apply to the use of

the liquid forms. The effective use of the liquids

depends on many things, including climatic conditions, type of soil, crop to be fertilized, and

tojDOgraphy, size, and other physical characteristics of the farm or field. There is no single liquid

nitrogen fertilizer that is best suited for all conditions.

Nitrogen Sorption

Retention of the ammonia in the pressui'e

liquids is difficult in certain soils and the higher

the ammonia concentration the more difficult it

becomes. The sandier soils do not retain ammonia so effectively as the soils with high clay or

organic matter content unless there are compensating factors, such as increased depth of application or increased soil moisture content. The finer

textured soils are generally best adapted to the

use of the high pi^essure solutions, although all

agricultural soils will retain the greater portion of

the nutritive value of the fertilizers. Nitratenitrogen, however, will leach badly under heavy

rainfall when nonpi^essure solutions are applied

to the surface of sandy soils.

The nitrogen in liquid nitrogen fertilizers is

sorbed by the soil in either the ammonium (NH^)

or nitrate (NO3) forms. The ammoniacal nitrogen in the solutions is present as ammonium hydroxide or as ammonium salts and is sorbed by

the soil as tlie ammonium ion. Anhydrous ammonia applied directly to the soil, combines with

the soil moisture to form the hydroxide and then

is sorbed as ammonium ion. Allison {17) reports

limited experiments showing that anhydrous ammonia and ammonium salts produced the same

quantities of fixed ammonium when added to soils

of high ammonium-fixing capacity. The ureanitrogen, according to Couturier and Perraud

{65), is converted to ammonium-nitrogen rapidly

and held by the soil in that form. Experimental

results show that under ideal conditions of temperature and moisture only 10 or 20 percent of

the ammonium fixed in the soil is available to

plants during the first 6 months. Under different

conditions and on different soils, about 90 percent

was available within a period of 3 months {17).

The nitrate-nitrogen in the solutions is sorbed in

readily available form.

Liquid nitrogen fertilizers hasten the decomposition of plant residues in the soil. Part of

the nitrogen is fixed by bacteria, fungi, and other

organisms active in the decomposition process.

This fixed nitrogen is only slowly available to

crops.

The movement and retention of liquid nitrogen

fertilizers in the soil is markedly affected by soil

texture. The critical constitutent of the liquids

in this regard is ammonia, and considerable research work has been done on its behavior in the

soil. McDowell and Smith {126) studied the

movement of ammonia in three soils under laboratory conditions. The ammonia was applied at the

rate of 100 pounds of nitrogen per acre in 40-inch

spacing. The treated soils were stored for 2
LIQUID NITKOGEN FERTILIZERS FOR DIRECT APPLICATION 25

months at 25° C, Avitli the moisture levels being

maintained at 70 percent of water-holding capacity. The ammonium- and nitrat«-nitrogen levels

were determined at the end of the storage period.

The results are given in table 15. Comparable

results were obtained by Stanley and Smith

{181). Blue and Eno {4.Jf) made field applications of ammonia on Arrendondo loamy fine

sand in rows 5 inches below the surface and 13.5

inches apart at rates of 58, 115, and 258 pounds

of nitrogen per acre. The added nitrogen spread

to a maximum distance of 8 inches from the point

of injection, and the major portion was retained

in an area 6 inches wide.

TABLE 15.—Distribution of ammonium- and nitrate-nitrogen at various distances from injection point of anhydrous ammonia^

TABLE 16.—Sorption and fixation of ammonia hy New

York soils ^

Concentration

Distance from injection

point (incties)

Dexter fine

sandy loam

Putnam silt

loam

Houston black

clay

Ammonium-NNltrate-N

Ammonium-N

Nitrate-N

Ammouimn-NNitrate-N

0-1

1-2--

P.p.m.

368

171

16

5

3

P.p.m.

669

402

133

7

5

P.p.m.

312

89

4

2

4

P.p.m.

913

533

52

26

29

P.p.m.

182

45

2

P.p.m.

1578

497

2-3

3-4

51

«— 4 29

Percent recovery oí

total nitrogen___ 93 9 80.2 72 6

' Data from McDowell and Smith {Í25). The soils received nitrogen at the

rate of 100 pounds per acre in 40-inch spacing and were stored for 2 months at

25° C. at a moisture level of 17 percent.

2 No anhydrous ammonia added.

Sohn and Peech {178) determined the quantity

of ammonia retained by representative Xew York

State soils. Air-drj^ soil in a glass bottle was

treated with gaseous ammonia mitil the soil was

saturated. The saturated soil was stored overnight in an atmosphere of ammonia in the stoppered bottle. Part of the ammoniacal soil was

allowed to aerate for 1 week, to remove physically

absorbed ammonia. The amounts of ammonia

taken up and fixed by the soils then were determined. Some of the results, given in table 16, show

that the interaction between ammonia and soil

matter is important in the Sorption of ammonia

by surface soils. The muck soils retained more ammonia than the mineral soils. Eetention was

also related to the soil pH. Acid soils containing

large amounts of organic matter fixed the largest

quantities of ammonia, with alkaline mineral soils

sorbing and fixing much lesser quantities.

Allison and associates {18) have shown that

the clay minerals, in addition to soil pH and organic matter content, have a marked effect on

ammonia fixation in soil. Considerable moist

fixation of ammonium-nitrogen may occur in soils

high m illite or vermiculite, and the fixation is increased by drying and heating. Montmorillonitic

clays fix little nitrogen unless heated. Surface

Soil type

pHof

original

sou

Organic

matter 2

Ammonia

Uptake 2 Fixed 2

Dunldrk: silt loam 7.15

4.20

6.62

4.25

7.25

6.68

5.05

4.70

4.10

6.52

3.92

4.90

6.10

4.90

Percent

2.54

2.30

3.15

3.04

3.18

3.15

3.38

4.15

3.50

2.37

2.14

90.7

77 7

63.2

Meg. per

100 g.

4.89

10.7

7.83

13.9

7.50

12.8

15.0

17.7

22.2

8.02

11.5

115.6

60.0

126.3

Meg. per

100 g.

0 94

Do . 1 40

Honeoye silt loam . . 1 34

Do _. 2 17

Mardln silt loam.. 2 01

Do 2.06

Do 3 46

Do.. 3 62

Do 5.31

Sassafras fine sandy loam

Do

1.16

1.83

Anderson muck 21.9

Dryer muck

Woody muck

12.4

22.0

1 Data from Sohn and Peech (178).

2 Iv'Ioisture-free basis.

soils fix less ammonium than the subsoils. This

is probably caused by the interfermg effect of organic matter and to the fact that the fixing capacity of the surface soil has already been satisfied

by potassium and ammonium.

The importance of soil moisture in the fixation

process appears to be related to the solubility of

ammonia in the soil solution. McDowell and

Smith {125) fomid the soil water to hold considerable ammonia and tliat movement of the

water exposed the ammonia to a greater volume of

soil. Laboratory studies by Blue and Eno {.^4-,

IfS) showed that the quantity of ammonia held in

sandy soils increased with increasing moisture

content. The increased quantity was apparently

in water solution, since, upon diying, the ammonia

content was no greater than if the ammonia had

been applied to the dry soil. Field applications

showecl no correlation between fixation and soil

moisture content.

Effect of Soil Properties and Population

Although a temporary increase in the soil pH

results from applications of anhydrous ammonia

and solutions containing ammonia, the ultimate

effect of the application of liquid nitrogen fertilizers is an increase in soil acidity. The magnitude of the potential acidity of the liquids is shown

in table 5. Laboratory experiments by Burgess

and Hawkins {53) showed that anhydrous ammonia might raise the soil pH initially as high as

9.5. Ayres and Humbert {29) found that the addition of 1,500 p.p.m. of nitrogen in the form of

aqua ammonia increased the pH of Onomea and

Waialua soils from 5.0 to 7.1 and 8.0, respectively,

and a calcareous soil from approximately 8.0 to

10.5. As nitrification of the ammonia proceeded,

the pH gradually dropped below the value exhibited originally.

From time to time, any excess acidity resulting

from the use of liquid nitrogen fertilizers must be

counteracted by liming, to maintain the soil pH
26 AGRICULTURE HANDBOOK 19 8, U.S. DEPARTMENT OF AGRICULTURE

values at their most efficient level for crop production. This is a major problem in some localities

where even the subsoils are becoming acid from

deep injections of ammonia. Tiedjens and Robbins {Ï87) and Blue and Eno {Jfß) state that ammonium-nitrogen is absorbed by plants most

rapidly in the pH range 7.0 to 8.0 and nitratenitrogen in the pH range 4.0 to 5.0. Very little

ammonium-nitrogen is absorbed by plants at pH

4.0. In general, a soil pH of 6 to 8 would appear

to be the most satisfactory for the use of liquid

nitrogen fertilizers.

The ammonia in the liquid nitrogen fertilizers

has a stimulating effect on nitrification, as shown

by Eno and Blue {81). The results obtained by

applying appropriate amounts of ammonium sulfate and ammonia to a Leon fine sand and incubating it at 82.4° F. are given in table 17. The

original reaction of the soil was pH 5.1. Maximum nitrification occurred when the reaction

after treatment was approximately 9.0 for both

the limed and unlimed soil. Higher initial pH

values, obtained by adding larger quantities of

ammonia, inhibited the activity of the nitrifiers.

The results in table 18 show that equivalent

amounts of nitrogen applied to Leon fine sand in

the form of urea or anhydrous ammonia affect

nitrification in a like manner. Other workers

{51,76, 79,80, 82,87) report ammonia levels in the

center of the application zone are high enough to

exert a toxic effect on the nitrifying bacteria.

Nitrate production proceeds from the periphery of

the concentrated area toward the center. As nitrification continues, the pH is reduced and the

ammonia is converted completely to nitrate.

Ammonia also ha.s a toxic effect on other members of the microbiological population of the soil.

Eno and his coworkers {79, 82) studied the effect

of anhydrous ammonia applications on fungi, bacteria, actinomycetes, and nematodes in sandy soils.

Applications of 100 pounds of nitrogen per acre

reduced the nmnber of fungi, bacteria, and actinomycetes (table 19). The toxic effects were restricted to a 3-inch zone around the injection point.

Reduction in the number of bacteria and actinomycetes persisted for less than 3 days, whereas

the depressing effect on fungi lasted for at least

38 days.

The toxic effect of ammonia increases with concentration (table 20). Nematode and fungi populations were reduced by all concentrations of

ammonia applied. Application of 608 p.p.m. of

nitrogen as ammonia was toxic to all but 0.6 percent of the nematodes and 4.9 percent of the fungi.

Concentrations of this magnitude are attained in

anhydrous ammonia application zones.

The ammonia in the liquid nitrogen fertilizers

also influences the availability of other soil nutrients. Stanley and Smith {181, 182) applied anhydrous ammonia to a silt loam at the rate of 100

TABLE 17.—Nitrification rates of anhydrous amtnonia ana ammonium sulfate in limed and unlimed Leon fine sand

and changes in pH soil ^

Ammonium sulfate inhydrous armnonla

No lime 2 tons of lime No lime 2 tons of lime

Time after fertilizer added and

quantity of ammonla-N Nltrate-N

pH

Nltrate-N

pH

Nltrate-N

pH

Nltrate-N

Quantity

Portion

of added

N

Quantity

Portion

of added

N

Quantity

Portion

of added

N

Quantity

Portion

of added

N

pH

Initial day for—

0 p p m

P.p.m. Percent

6.1

4.1

3.9

4.1

4.0

5.3

4.6

4.5

4.6

4.3

6.3

4.4

4.4

4.3

4.2

4.8

4.6

4.4

4.4

4.2

4.2

4.6

4.5

4.3

4.3

P.p.m. Percent

7.6

7.9

7.9

7.8

7.8

6.9

6.0

6.9

6.8

6.7

6.8

6.9

6.8

6.8

6.9

6.3

6.2

6.1

5.4

5.5

6.2

4.6

4.6

4.6

6.6

P.p.m. Percent

5.1

6.1

7.8

9.1

9.6

5.3

6.6

7.0

7.8

8.7

5.3

6.1

6.5

6.0

8.6

4.8

5.7

6.1

6.5

7.8

4.2

4.8

6.0

5.4

6.8

P.p.m. Percent

7.6

8.6

9.1

380 p.p.m 9.5

780 p P m 9.8

At 14 days for—

0

0

0

0

0

0

0

0

0

0

4

0

0

0

0

21

0

0

0

0

0

0

0

0

0

16

0

0

0

0

37

31

25

8

9

50

77

68

69

2

0

0

0

4

2

0

0

27

96

0

4

33

58

119

19

21

48

81

116

100

0

0

0

4

0

16

84

106

30

3

37

100

130

74

18

60

97

124

84

6.9

62 p.p.m

203 p p m. . _

0

0

0

0

0

0

0

0

0

0

1.1

0.3

0

0

1.1

0

7.6

7.8

380 p.p.m

780 p.p.m..

At 28 days for—

n p p TTi

8.2

8.8

6.8

92 p.p.m

203 p.p.m...

380 p.p.m

780 p.p.m

At 42 days for—

0

0

0

0

0

0

0

0

0

13.3

25.0

0

73.9

44.3

36.83

0

5,0

6.2

6.9

8.1

6.3

92 p p m . - 0

0

0

0

0

0

0

0

31.5

26.6

30.3

1.9

68.5

45.8

9.7

0

4.6

203 P P m - - - 4.7

380 P P m . - 6.2

780 p.p.m....

At 63 days for—

7.6

6.2

.'-P.p.m...

2{<i ¡).p,m

asop.p.Ri

780p.p.m...

0

0

0

0

29.3

8.9

2.4

0

29.3

29.6

26.0

10.1

51.1

36.6

8.9

4.7

4.6

6.6

6.4

' Data from Eno and Blue (.81).
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION 27

TABLE 18—Nitriñcation rates of urea and anhydrous ammonia in limed and unlimed Leon fine sand and changes in pH

^ of soil^

Urea Anhydrous ammonia

Time after fertilizer added and

No lime 2 tons of lime No lime 2 tons of lime

quantity of ammonia-N

Nitrate-N

pH

Nitrate-N

pH

Nitrate-N

pH

Nitrate-N

Quantity Portion of

added N

Quantity Portion of

added N

Quantity Portion of

added N

Quantity Portion of

added N

pH

Initial day for— P.p.m. Percent

5.5

6.8

5.8

5.8

6.8

5.7

6.2

6.8

8.8

8.9

5.4

5.0

5.4

7.8

8.8

P.p.m. Percent P.p.m. Percent

5.6

6.6

7.3

8.0

8.6

6.7

6.0

6.1

8.4

8.9

5.4

4.8

6.1

7.6

8.7

P.p.m. Percent

129 p.p.m -

887 p.p.m -

At 14 days for—

12

65

106

8

7

22

84

123

24

1

29

105

96

9

7

42

118

155

35

3

6.9

6.7

7.3

8.7

9.0

7.1

6.6

6.3

8.0

8.8

12

73

141

11

8

22

112

163

17

0

29

106

69

22

8

42

122

88

42

0

6.9

129 p.p.m.._

335 p.p.m

41.1

28.1

0

0

58.9

19.7

0

0

47.3

38.6

0

0

69.7

11.9

0

0

6.6

7.0

8.6

887 p.p.m ---

At 28 days for—

8.9

7.1

129 p.p.m

335 p.p.m_ --

600 p.p.m

887 p.p.m

48.1

30.1

.3

0

58.9

33.7

0

0

69.8

42.1

0

0

62.0

13.7

0

0

6.4

6.6

7.7

8.8

' Data from Eno and Blue (81).

TABLE 19.—Net effect of anhydrous ammonia on the numbers of fungi, bacteria, and actinomycetes in loamy fine

sand^

FUNGI

TABLE 20.—The effect of anhydrous ammonia on the numbers of fungi and nem,atodes in Arredondo fine sand ^

Sou

moisture

Numbers per gram of oven-dry soil at 2—

Days after treatment

Point of

Injection

llQCh

from

point of

injection

2 Inches

from

point of

Injection

3 inches

from

point of

Injection

0

Percent

-16.00

-9.87

-6.75

-13.00

-6.67

-20.00

Thousands

-2.00

-6.62

-6.87

-7.50

-4.17

-12.17

Thousands

-0.88

-1.87

-4.12

0

+4.60

-12. 60

Thousands

-1.13

+1.00

-1.76

-2.50

-2.17

-6.67

Thousands

4.2

3

10

4.4

6.3

24 1.8

31 .. . . . 4.8

38 1.6

BACTERIA

0-

3_.

10.

24„

31.

38..

Millions Millions Millions

-1. 987 +2. 350 -1.076 -0. 287

--4.989 +4.189 +.739 +.802

--6.112 +3.162 -.738 -.713

--2. 850 -.166 +.600 +.500

--1.167 +.300 +3.233 +1.084

-.026 -.175 -.358 +.225

Millions

4.2

4.4

6.3

1.8

4.8

1.6

ACTINOMYCETES

0..,

3...

10..

24..

31..

38..

-1.062 -0. 776 -0. 262 -0.126

+.049 +.274 +.174 -.076

+1. 087 +.612 --.138 -.102

+.767 +.184 --.084 +.260

--.633 +.316 --.200 +.133

+.325 +.308 +.192 +.126

4.2

4.4

5.3

1.8

4.8

1.6

1 Data from Eno and Blue (79); ammonia applied at a rate of 100 pounds

of nitrogen per acre.

' Numbers in ammonia-treated sou minus numbers in untreated soil.

pounds of nitrogen per acre and found after an

interval of 8 weeks that the soil pH had. been

affected to a distance of a.bout 4 inches from the

point of injection. The added ammonia increased

the availability of the soil phosphorus and potassium and reduced the readily available calcium.

NH3-N added (p.p.m.) pH Nematodes 2 Fungís

0 -.-

136.-.. _

292

366

6.7

8.4

9.0

9.2

9.4

9.5

367

241

116

60

2

1

61.0

58.0

56.2

49.2

608

741

3.0

1.2

1 Data from Eno, Blue, and Good (82).

' Number per 160 miUUiters of moist soil.

3 Number per gram of oven-dry soU.

Total exchangeable calcium, however, was not

affected.

Nitrogen Losses After Application

]\Iost of the studies of nitrogen losses that occur

after liquid nitrogen fertilizers are applied to the

soil have been made with anhydrous and aqua ammonia. Tlie possible losses incurred by the other

constituents of nitrogen solutions are usually based

on studies of the behavior of the different materials when applied separately.

Jackson and Chang {102) investigated the possible nitrogen losses due to the volatilization of

anhydrous ammonia injected at various depths in

some Wisconsin soils. A beaker containing approximately a 5-inch layer of soil was placed in a

desiccator, and anliydrous annnonia was injected

at the desired depths. The desiccator was repeatedly exhausted through an acid trap to collect the

escaping ammonia. A 2y2-minute cycle of exhaustion followed by admission of air was continued

for 30 minutes. The results in table '^1 show that

a large proportion of the ammoni'^ applied at the

surface of soils escaped into tlie air. The authors

conclude that a soil of intcnnediate texture, mois-
2S AGRICULTURE HANDBOOK 19 8, U.S. DEPARTMENT OF AGRICULTURE

TABLE 21.—Loss of anhydrous ammonia nitrogen injected TABLE 22.—Losa of nitrogen from California soil^

into Wisconsin soils ^

Soil type, treatment, pH value,

and soil moisture

Beach sand:

Air-dry. _.

Field moisture (7.7 percent).

Platnfleld sand:

From cultivated field (pH

6.0)—

Air-dry

Field moisture (9.1 percent).

Excessively limed (pH 7.7)—

Air-dry

Field moisture (9.1 percent).

Crosby silt loam:

From cultivated field (pH

6.4)—

Air-dry

Field moisture (15.3 percent)

Excessively limed (pH 7.6)—

Air-dry

Field moisture (15.9 percent)

NajCOa treated (pH 10.5)—

Air-dry

Field moisture (18.9 percent)

Losses of the added nitrogen applied at

60 pounds per acre at depths ol—

0

inch

Percent

93

81

49

0.5

inch

Percent

29. i

37.1

1.0

inch

Percent

16.5

6.1

27.6

11.6

12

34

24.2

19.3

2.0

taches

Percent

90.6

29.3

6.7

0

17.7

0

0

0

6.6

0

'4.0

inches

Percent

81

' Data from Jackson and Chang (ÍOI).

ture content, and pH value sliould completely sorb

the equivalent of 60 pounds of nitrogen per acre

applied in the form of ammonia at a depth of 1 to

2 inches.

Stanley and Smith (181) state that ammonia

applied at the rate of 100 pounds per acre in 40-

inch rows 3 to 4 inches below the surface is more

than many soils can sorb. The excess ammonia

will be lost immediately or held as ammonium

hydroxide in solution subject to later loss if the

ammonium hydroxide evaporates from the surface of the soil. Such losses are generally eliminated by applying the ammonia at a depth of 6

inches. On the other hand, Baker and coworkers

(3.1) state that losses are negligibly small when

anhydrous ammonia is applied, even to a depth

of only 4 inches, to soils with optimum moisture

contents.

Martin and Chapman (1S7) found in the laboratory that nitrogen losses occur when ammonia is

present at or near the surface of an alkaline soil.

Nitrogenous fertilizers were mixed with or added

in a solution to 2-inch layers of soil, and the volatilized ammonia was collected and measured.

After the soil became dry, it was remoistened and

ammonia collection repeated. This was continued

until little or no ammonia was recovered. The

addition of ammonium hydroxide or urea raised

the soil pH; the extent and duration of the temporary alkalinity depended on the buffering capacity of the soil. Nitrogen losses, accounting

for as much as 51 percent, are shown in table 22.

The acid sandy loam, in this case, had a low

buffering capacity.

Additional work by the same authors (138)

shows that ammonia-nitrogen losses of 9 and 17

percent occur when ammonium hydroxide is apNitrogen

added

Loss of nitrogen by volatill?.ation

from—

Nitrogen source

Clay loam

(pH 8.0)

Sandy

loam

(pH 7.5)

Sandy

loam

(pH 6.7)

Ammonium sulfate _

Ammonium hydroxide...

Urea - - -

Pounds

per acre

Í 150

1 250

/ 150

I 260

250

250

Percent

23

25

27

28

16

22

Percent

26

19

36

34

16

14

Percent

6

4

51

41

36

Ammonium nitrate 2

' Data from Martm and Chapman (137).

plied at the rate of 150 pounds of nitrogen per

acre to soils with an initial pH of 4.5 and 4.6

respectively. The losses are caused by the temporary alkalinity of the soil resulting from the

ammonium hydroxide and the losses increase with

higher temperatures.

The application of low-pressure ammonia-ammonium nitrate-water solutions to the soil surface

also incurs nitrogen losses. Trickey and Smith

(IW) showed that Solution LP-6 (see table 5)

applied at a rate of 100 pounds of nitrogen per

acre at a temperature of 73° to 75° F. lost 28.2

percent of the ammonia ( 14.9 percent of the nitrogen) in the first hour. Losses continued for some

time and were greater at the lower soil moistures

and higher atmospheric and soil temperatures.

The loss of volatile ammonia-nitrogen over a

period of time from an experimental solution

similar to Solution LP^ has been demonstrated by

Robertson and Hansen {160). The solution was

dribbled on the surface of the soil at five locations

and the ammonia-nitrogen losses determined. The

results in table 23 show that the losses were proTABLB 23.—Losses of ammonia from surface applications

of a low-pressure nitrogen solution^

Soil type Application rate ^

Total volatile nitrogen lost at time

Intervals of—

25mtautes

60mtautes100 minutes200 minutes

400 minutes

Conover loam s

Hlllsdale loam <

HlUsdale loam '

Hlllsdale loam s

Kalamazoo sandy

Pound N

per acre

25

50

100

25

\ 60

100

25

50

100

26

{ 50

100

25

\ 50

[ 100

Pounds

per acre

1.9

3.7

7.5

2.2

4.0

7.9

2.0

3.9

7.9

2.0

4.0

8.1

2.1

4.3

8.8

Pounds

per acre

2.1

4.2

8.6

2.6

4.6

9.0

2.2

4.5

8.9

2.3

4.7

9.2

2.3

4.8

13.6

Pounds

per acre

2.6

4.9

9.7

2.8

5.4

10.1

2.6

6.2

10.0

2.5

5.4

10.2

2.5

6.4

16.0

Pounds

per acre

2.9

5.6

11.2

4.2

6.0

11.4

2.8

5.8

11.2

2.7

6.0

11.3

2.9

6.3

16.8

Pounds

per acre

3.1

6.0

12.6

4.4

6.6

12.7

3.0

6.2

12.6

2.9

6.6

12.4

3.1

6.8

18.2

' Data from Robertson and Hansen (180).

2 Solution application rates of 26, 60, and 100 pounds of N per acre supply

4.6, 9.1, and 18.3 pounds, respectively, of volatile ammonia-nitrogen per

acre.

3 Cornfield with dry, crusted soil.

1 Wheatfleld with dry, granular soil.

' Cornfield with wet, crusted soil.
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION 29

portional to the level of application and ranged

from 63 to 100 percent of the ammonia-nitrogen

applied.

Some nitrogen loss may also result from the

leaching of the nitrates present in the solutions or

formed bj^ the nitrification of ammonium-nitrogen. Nitrate formation varies with temperature

{20, M, 86,129,163). It does not begin until the

temperature rises above freezing, after "which the

rate of formation increases with temperature.

Very little nitrification occurs under field conditions after soil temperatures drop below 40° to

50°F. Laboratory results obtained by Anderson

and Purvis {21) on the temperature-nitrification

relationship are given in table 24.

TABLE 24.—Infltience of temperature on nitrification of

ammonium hydroxide ^ in Nixon sandy loam., New Jersey '

Incubation period (days)

Nitrate content of samples derived

from applied nitrogen at—

37° F. 42° F. 47° F. 52° F.

7

Parts

per

million

0

.8

0

2.0

3.2

4.8

Parts

per

million

0

.8

1.6

5.6

6.4

17.6

Parts

per

million

0

2.4

6.1

18.4

22.4

36.0

Parts

per

million

14 4 0

21 15 2

28— .... 22 4

35 37 6

42

1 Applied at the rate of 100 p.p.m. N.

' Data from Anderson and Pm-vls (2i).

Urea-nitrogen in solutions may be lost as such

or after conversion to ammonia and nitrate forms.

Fisher and Parks (5.^) report that urea hydrolysis

is relatively slow at 50° F., so that losses below

this temperature are probably due to the leacliing

of urea. Significant hj^drolysis occurs above 50°

F., and, once hydrolysis occurs, nitrogen losses

will follow ÛiQ pattern of ammonia-nitrogen

losses. The rate of hydrolysis and subsequent nitrification increases with increasing temperature.

Volk {197) determiiied the gaseous losses of

ammonia-nitrogen over a period of 7 days after

surface applications of urea to a nmnber of soils.

The 7-day period was selected, as the loss by volatization was about 95 percent completed in that

time. A maximum nitrogen loss of 59 percent was

obtained when pelleted urea was adcled to bare

moist Lakeland fine sand II (cf. table 25) at the

TABLE 2.5.—Gaseous losses of nitrogen during 7 days following surface application of a urea-ammonium nitrate

solution to hare moist soil in Florida at the rate of 100

pounds of nitrogen per acre^

Sou Soil pH

Cation exchange capacity of the

soil

Isitrogen

loss from solution NP13 2

Lakeland fine sand I 5.6

6.3

5.4

6.7

6.3

4.4

5.9

5.3

6.8

5.9

7.8

Meg. per

100 g.

1.5

1.6

4.7

3.5

1.9

2.8

5.8

7.2

11.5

23.4

7.4

Percent

0 6

Lakeland fine sand 11 29 4

Lakeland fine sand ni... 1 6

Lakeland fine sand IV 15 2

Lakeland fine sand V.. . 4 4

Leon fine sand .. .... 3 2

Leon fine sand.. 7 5

Bed Bay fine sandy loam .. 2 3

Arredondo fine sandy loam 4

Fellowship fine sandy loam 1

Perrine marl. 14 4

1 Data from Volk (197).

' Contained 32 percent nitrogen—16.5 percent from urea and 15.5 percent

from ammonium nitrate.

rate of 100 pounds of nitrogen per acre. Volatile

nitrogen losses resulting from the application of a

urea-anmionium nitrate solution to bare moist

soil are given in table 25. The losses were smaller

than those obtamed with pelleted urea. However,

if the loss on Lakeland fine sand II is attributed

to tlie urea fraction, it amomits to over 57 percent of the urea-nitrogen. Nitrogen losses from

bare soil were much smaller when the irrea was

applied to dry or cold soils. When applied to

well-developecl sods at the rate of 100 pounds of

nitrogen per acre, the average volatile nitrogen

losses from pelleted urea and the urea-ammonium

nitrate solution were 20.6 and 11.5 percent,

respectively.

More recent work by Kresge and Satchell {llß)

showed no appreciable ammonia volatilization

losses when less than 100 pomids of nitrogen per

acre were topdressed in the form of solid urea on

a bare silt loam with a pH value of 6.3. A bermudagrass cover significantly reduced the losses

occurring at higher rates of application on bare

soils. Losses from a water solution of urea (23

percent N), surface-applied at a rate of 316

pounds of nitrogen per acre, amomited to 74.2 percent of the nitrogen on a sandy loam and 79.4 percent on a silt loam in a period of 11 days. Ammonimn nitrate mixed with urea in concentrated

solutions reduced the aimnonia volatilization

occurring with solutions of urea alone.

TIME OF APPLICATION

The use of liquid nitrogen fertilizers, particularly ammonia and aqua ammonia, presents the

possibility of fall application of nitrogen for use

by the crops in the spring. The ammonia is fixed

by the soil and its conversion to leachable forms

is retarded by low soil temperatures and completely stopped at temperatures below freezing.

Mclntosh and Frederick {129) in Iowa found

that ammonia-nitrogen applied in November just

prior to freezing showed little nitrification before

March. Rapid nitrification began in mid-April

and approximately 8 weeks were recpired to comIDlete nitrification of the ammonia. MacGregor

{127) states that, generally, nitrogen applied in

the late fall on the medium- to fine-textured soils

in Llinnesota was equally as effective as that applied during the spring. Overwinter losses of

nitrogen were not evident.

Nitrogen losses during the winter are due primarily to erosion and to leaching. Care should

be taken to select areas not suljject to erosion for

surface applications in the fall. Subsurface ap-
30 AGRICULTURE HANDBOOK 19 8, U.S. DEPARTMENT OF AGRICULTURE

plications minimize erosion losses but are subject

to leacliing. Where percolation occurs, the nitrate-nitrogen is leached out of the root zone

while the ammoniacal-nitrogen is held by the

soil until converted to nitrate. Nelsoii and Uhland {lliß) classify various areas on the basis of

practicability of fall application of nitrogen in

figure 16. Area I is best suited for fall applicaf\

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FIGURE 16.—Suitability of certain geographic areas for

fall application of fertilizer ranging from the most

suitable (area I) to least suitable (area IV). Nelson

and Uhland m%).

tion, since leaching losses are milikely because of

the normally low rainfall. Area II includes sections either of relatively low percolation or low

fall temperatures, or a combination of both. This

area should be suitable for fall applications of

ammoniacal-nitrogen, but nitrat« applications

should be limited to sections where percolation is

relatively low. Fall application of liquid nitrogen

fertilizers would appear to be questionable in area

III and undesirable in area IV except for fallplanted crops that require nitrogen or for plants

that grow during a good part of the winter. Fall

plow-down applications of liquid nitrogen fertilizers are suitable for such crops in any area.

Split applications of fertilizer, particularly

nitrogen carriers, are favored by many. The first

application is made previous to planting. The

second is made as the plant approaches its most

rapid period of growth and greatest need for nitrogen. This practice lessens the danger of seed

injury and provides the plant with adequate supplies of nitrogen when they are most needed.

Anhydrous and aqua ammonia are often used

for preplant application on row crops. The ammonia is normally applied 10 days to 3 weeks before planting, after which the land is left undisturbed until the crop is planted. This prevents

seed and seedling damage by allowing the ammonia to diffuse through the soil and to be fixed

by the soil particles.

The solutions containing ammonium nitrate are

most efficiently used if applied at the time plant

requirements for nitrogen are high. This time

varies with the crop. The liquid is applied preAaous to the major vegetative growth and is of

little value if added too late. For example, sidedressing corn at the last cultivation is beneficial,

since leafy crops need nitrogen late in the growing

season.

Application on Small Grains

The effect of time of application on winter

wheat yields was studied by Lowrey and his coworkers {l^If) in Nebraska. The results are given

in table 26. Phosphate applications were made

with the seed, ammonium nitrate was applied as

a topdressing, and anhydrous ammonia was injected 6 inches deep. Little difference in wheat

yields was found between fall and spring applications of ammoniimi nitrate or between ammonium

nitrate and fall applications of anhydrous ammonia. The lower yields from spring applications

of anhydrous ammonia were probably due to unfavorable soil conditions at the time of application. Part of the decrease in yield may be due to

mechanical injury to the stand, which Eck and

his coworkers {77) found might occur from spring

application of anhydrous ammonia to wheat.

Olson and Rhoades {151), however, found anhydrous ammonia applied 4 to 5 inches deep prior

to planting in the fall or early spring was as effective in promoting the growth of winter wheat as

ammonium nitrate broadcast either in the fall or

in the spring. The response to ammonium nitrate

substantially was independent of time of application, whereas spring application of anhydrous

ammonia was somewhat less effective. Their experiments Avere carried out in eastern Nebraska on

Sharpsburg silt loam in 1948, 1949, and 1950 and

on Crete silty clay loam in 1952. A basal applicaTABLE 26.—Response of winter wheat to anhydrous ammonia and ammonium, nitrate in Nebraska^

Treatment 2 Yield

Source oí nitrogen

N P2O6 K2O Saline

County

Seward

County

None -

Pounds

per acre

0

40(F)

40(S)

40(F)

40(S)

Pounds

per acre

30

30

30

30

30

Pounds

per acre

0

0

0

0

0

Bushels

per acre

36

45

38

48

46

Bushels

per acre

9

Anhydrous canmonia.-

Do

24

11

Amonium nitrate

Do

21

20

4 4

' Data from Lowrey, Olson, Dreier, and Ehlers (/Í4).

2 (F)=faU application, (S)=sprtng application.
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION 31

tion equivalent to 45 pounds of pliosphoric oxide

was made with the seed at planting time; potash

was assumed to be adequate. The results of these

experiments are given in table 27.

Under the climatic conditions prevailing in Mississippi, anhydrous ammonia applied in the fall

was superior to fall-applied ammoniuna nitrate as

a source of nitrogen for fall-sown oats (^7).

Table 28 further shows that fall-applied ammonia

was more eifective than spring-applied ammonium

nitrate on the more acid soils but less effective on

the soils with pH values above 5.1. The ineffectiveness of the fall-applied anhydrous ammonia

on these latter soils was attributed to the more

rapid conversion of ammonia to nitrates and subsequent leaching losses.

TABLE 27.—Response of winter wheat to anhydrous ammonia and ammonium nitrate in Nebraska ^

TABLE 28.~The response of oats in Mississippi to fall-applied anhydrous ammonia and to fall- and spring-applied

ammonium nitrate—32 pounds of nitrogen per acre""

Increase in yield due toSoil Nos. and pH Anhydrous

ammonia

applied in

fall

Ammonium nitrate

applied in—

Fall Spring

Soils with pH 5.1 or below:

1

Bushels per

acre

30

32

30

29

19

25

12

15

14

4

Bushels per

acre

16

15

16

20

10

15

8

8

10

5

Bushels per

acre

2 25

3 25

4 2 27

5». 19

Soils above pH 5.1:

30

7__._ 19

8 22

9 24

10' 24

Year and source of nitrogen Time of application Mean

yield

1948!

Anhydrous ammonia .. . September

do

Bushels

per acre

Ammonium nitrate . ,..._.. 48 6

Check 35 8

1943 3

Anhydrous ammonia . - - _ September

do

33 8

Ammonium nitrate. . 33 1

Anhydrous ammonia. April. 27 3

Ammonium nitrate . , . 32 8

Check 30 8

1950 Î

ATlhvdrnuR ammonia September..

do

40 2

Ammonium nitrate. 35 7

Check 31 4

1952*

Anhydrous armnonia April

do

32 5

Ammonium nitrate. 35 5

Check... 22 0

1 Data from Olson and Rhoades {161).

' Mean yields obtained with 30 to 60 pounds of nitrogen per acre. Î Mean yields obtained with 20, 40, and 60 pounds of nitrogen per acre.

* 60 pounds of nitrogen per acre.

' Data from Andrews, Neoly, and Edwards {27).

! pH 4.95.

•pHS.l.

< pH 7.8.

Application to Crops for Grazing

The time for applying nitrogen fertilizers to

crops for grazing depends to a large extent on the

time of seeding and the ultimate use of the crop.

Thompson {186) points out that there are three

planting periods for winter grazing in Mississippi.

Cereals, fescue, and i-yegrass can be planted in

early and late September and October so that at

least part of the required nitrogen should be applied at the time of seeding. Alarch and early

April applications supply early and luxuriant

extra pasturage, whereas applications made in the

late simimer are effective when fall pasturage is

desired. Early spring applications are also recommended when a hay crop is to be harvested.

SELECTION OF LIQUID NITROGEN FERTILIZER

The selection of a liquid nitrogen fertilizer is

governed to a limited extent by the type of crop to

be fertilized, but no hard and fast rule can be

given. The pressure liquids, which should be injected in the soil, find their greatest use in side

dressing row crops, but care must be taken not to

place these liquids too close to young seedlings at

time of planting or transplanting. Lorenz,

Bishop, and Wright {121) observed toxic injury

to_ onion and potato seedlings in light-textured

soils by this practice, whereas similar placement

of anmionium sulfate caused no injury. The toxic

condition remained for some time and was related

to the greater upward movement in the soil of the

ammonia from the pressure liquids. Subsurface

application to growing row crops prevents burning and can be carried out without excessive damage to the root system. Root-system damage has

been a deterrent to the use of pressure liquids on

pastures and for cereals, but current research may

solve some of these difficulties. The nonpressure

liquids do not require soil injection, but they may

cause slight burning upon contact with the foliage.

This is soon offset by the stimulated growth that

follows. Greater use has been made of the nonpressure liquids than of the pressure liquids for

pastures, hayland, and cereal crops and for application during seeding.

TABLE 29.—Percentage of applied nitrogen recovered in

forage crops

Source and quantity of

nitrogen applied per acre

Applied nitrogen recovered In—

Sodium

nitrate

Ammonium

nitrate '

BermudagrassOrchardgrass

Tall fescue Bromegrass

Pounds N

50

Pounds N Percent

42.3

6Ó'2"

Percent Percent Percent

80 83 78 30

100

160 84 76 26

200 65.7

240 69

400 64.4

1 Data from Burton and DeVane {54); Tiiton , mdy loam in Georgia,

2 Data from Wagner (,199); Codorus silt loam limed to pH 6.5, Marj Maryland.
32 AGRICULTURE HANDBOOK 19 8, U.S. DEPARTMENT OF AGRICULTURE

Crop utilization of applied nitrogen fertilizers

is of major importance, but little if any work has

been done on the uptake of nitrogen from liquid

sources. Most of the studies on nitrogen utilization have been made with solid forms of nitrogen,

but liquid forms may be expected to give comparable results. The percentage of nitrogen applied in solid form and recovered in forage crops

the first season has been determined by Wagner

{199) at Beltsville, Md., and Burton and DeVane

(54) at Tifton, Ga., with results as shown in table

29. It is assumed that a part of the unused applied

nitrogen will be held in a slowly available form

and utilized in part in subsequent years.

CROP RESPONSE

The advent of liquid sources of nitrogen for

use as fertilizer has raised many questions and

presented many problems that are being investigated in a number of institutions. The relative

value of this form of nitrogen in comparison with

the customary solid nitrogen carriers is of primary importance. Considerable research work

has been conducted on this subject. The comparisons, in general, have been between anhydrous

ammonia and solid ammonium nitrate. Some

comparisons have been made between liquid nitrogen fertilizers and solid ammonium nitrate. Solid

ammonium nitrate has been chosen as a standard

because it introduces no accompanying ion or other

constituents that might produce beneficial or

detrimental side-etïects upon plant growth. A

summary of some of the experimental results is

given here. The response data indicate that the

total nutritive value of nitrogen, when properly

applied, is the same, irrespective of the form in

which it is used. Any preference among liquids

must be based on the ratio of nitrate-, urea-, and

ammoniacal-nitrogen content.

Corn

Studies of the use of liquid forms of nitrogen

for fertilizing com have been rather extensive,

owing to the widespread cultivation of the crop,

its high nitrogen requirement, and the responses

obtained from the use of nitrogen.

Work by Lowrey and Ehlers [123) in Nebraska

shows there is no appreciable difference between

corn yields obtained with anhydrous ammonia or

ammonium nitrate. Yields were similar for both

materials applied prior to planting or sidedressed

when the corn was 10 to 18 inches tall. However,

results, although not conclusive, indicate that sidedressings of anhydrous ammonia may be sujierior

to earlier applications. MacGregor {126) found

anhydrous ammonia sidedressing substantially increased yields of both corn and protein per acre

in Minnesota, provided there was an adequate supply of available phosphorus and potassium in

the soil.

Chandler {67) compared the use of anhydrous

ammonia, solution NP-13, ammonium nitrate, and

other solid nitrogen materials as sources of nitrogen for corn in North Carolina. Anhydrous ammonia and solution NP-13 were fully as effective

as the Solid forms of nitrogen in promoting the

growth of corn.

These observations with respect to anhydrous

ammonia have been confirmed by the work of

Andrews and his coworkers {27) in Mississippi,

the results of which are given in table 30. In

general, anhydrous ammonia was fully as effective

as anunonium nitrate in promoting the growth

of corn. The average yield increase obtained with

sidedressed applications of anhydrous ammonia

was greater than that obtained with preplanted

applications.

TABLE 30.—Average response of corn to anhydrous ammonia and ammonium nitrate applied at various locations in Mississippi ^

Anhydrous

ammonia

Ammonium nitrate Check

Location

Preplant,

4 inches

deep

Sidedress,

4 inches

deep

Preplant,

4 inches

deep

Sidedress,

4 inches

deep

Sidedress,

on the

surface

No

nitrogen

applied

Columbus

Starkville

Tomnnlpn

Bushels

per acre

28.3

26.0

56.1

84.6

60.5

Bushels

per acre

27.4

34.6

57.8

79.1

69.5

Bushels

per acre

24.2

21.8

55.3

82 8

66.3

Bushels

per acre

27.8

28.7

55.3

79.5

62.3

Bushels

per aae

28.5

26.2

54.6

80.6

63.7

Bushels

per acre

12.1

12.4

42.8

Holly Springs

Do

69.9

56.0

Average 51.1 63.7 50.1 50.7 50.7 38.6

Average increase 12.5 15.1 11.5 12.1 12.1

1 Data from Andrews and coworkers (Ä7); nitrogen applied at the rate of

32 pounds per acre.

Cotton

Some of the earliest field experiments using

anhydrous ammonia as a source of nitrogen in cotton culture were, carried out in Mississippi. Andrews and his coworkers {27) compared the

relative efficiencies of anhydrous ammonia and

ammonium nitrate and found nitrogen in either

form was about equally available to the cotton

plant. Greater variations in yield occur as a result of fertilizer placement and time of application rather than from different sources of nitrogen.

Oakes {160) reports that the production of seed

cotton fertilized with ammonia was comparable in

practically all cases to the yields obtained with

ammonium nitrate, ammonium sulfate, or sodium

nitrate. No significant differences were observed

in the yields obtained either from preplanting or

from sidedressing applications. Table 31 gives

the results obtained with applications of 40

pounds of nitrogen per acre in the Eed River Valley of Louisiana.

An evaluation of nitrogen carriers under irrigation conditions was made by Mikkelsen and Smith
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION 33

TABLE 31.~8eed cotton yields obtained in Louisiana ivith

40 pounds of nitrogen per acre, 1950-53

Source of nitrogen and time of

application

Seed cotton yields per acre

1950 1951 1952 1953

Applied 10 days before planting: Pounds

2,185

2,213

2,038

2,129

2,355

2,212

2,318

2,164

Pounds

1,579

1,324

1,465

1,375

1,259

1,025

1,118

1,490

Pounds

2,791

2,950

2,806

2, 969

2,937

2,779

2,557

2,832

Pounds

2 923

Ammonium nitrate 2 919

2 959

Sodium nitrate 2; 865

2,872

2 978

Sldedressed:

Ammonia, anhydrous. _._

Ammonium sulfate 2,904

Sodium nitrate 2,926

1 Data from Oakes {ISO).

(HI) in California. The results are given in

table 32. The comparisons were made on soils

under continuous cotton production. Aqua ammonia and the dry materials were applied in 2

bands 6 inches each side and 3 to 5 inches below the

seed. Anhj'drous ammonia was applied in the

middle of each row to a depth of 6 inches. The

test plots received a basal application of 100

pounds of available phosphoric oxide per acre;

potash was assumed to be adequate. Marked increases in seed cotton yields were obtained from

the use of nitrogen on both soils, but no significant

differences wei'e noted in the cotton-producing efficiencies of anhydrous ammonia, aqua ammonia,

ammonium nitrate, and ammonium sulfate.

Yields obtained in 1952 with calcium nitrate and

urea were significantlj' lower than those obtained

with aqua ammonia.

Bhat, Ingreji, and Patel (^0) studied the relative cotton-producing efficiency of ammonia liquor

in India in 1953-54. Aqua ammonia and ammonium sulfate were drilled into the soil midway

between the cotton rows. Nitrogen fertilization

increased both the seed cotton yield and plant

weight significantly, with both sources of nitrogen

giving almost identical results.

TABLE 32.—Relative efficiency of nitroffeti sources on seed

cotton production in California^

Seed cotton yields per acre on—

Nitrogen source Hesperia sandy loam ' Panoche

loam'

1951 1952 1952

Ammonia, anhydrous

Pounds Pounds Pounds

3 767

Ammonia, aqua 2,705

2,727

3,051

2,489

2,748

2,142

3,053

2,858

2,966

2,620

2, 728

1,537

3,999

Ammonium nitrate 3 798

Ammonium sulfate ..

Calcium nitrate

Irea...

3,938

3,858

3 752 Check.. 0 Q32

L.S.D. at the 5-percent level 366 279 353

Hay and Pasture

The relative efficiency of anhydrous ammonia as

compared with ammonium nitrate for the production of oats for fall and winter forage was determined by Hammons (94) on three sandy loams

in Mississippi. Anhydrous ammonia was applied

6 inches deep the day before planting and the ammonium nitrate was applied 2 weeks later as a topdressing. Each plot received a basal application

of phosphorus and potassium. Grazing was simulated by clipping on December 4 and February 14.

The forage yields are given in table 33. Anhydrous ammonia was more efï'ective than ammonium

nitrate for the production of forage on Savannah

soil, and the two nitrogen carriers were equally

effective on Ora soil. A spot clipping on January 24 indicated that 75 percent -of the nitrogen

applied to the Ora soil had been assimilated. The

fall-applied nitrogen had little influence on the

grain yields from Savannah soil and no influence

on the yields from Ora soil.

TABLE 3.3.—Response of fall-planted oats to anhydrous

ammonia and ammonium nitrate on two Mississippi

soils^

Quantity of

nitrogen added

per acre

Yield per acre of oven-dry forage

from—

Source of nitrogen Ora very fine

sandy loam 2

Savannah fine

Fall Spring

sandy loam '

Dec. 4 Feb. 14 Dec. 4 Feb.14

.\mmonia

Ammonium nitrate

Do

Pounds

32

32

64

64

32

32

Pounds

0

0

0

0

32

32

Pounds

737

598

1,394

1,343

721

639

Pounds

185

161

233

239

223

181

Pounds

481

281

494

863

476

218

Pounds

138

100

209

.Ammonia 213

Do 129

.ammonium nitrate 87

' Data from Mikkelsen and Smith (IJ,t).

* Received 80 pounds of nitrogen and 100 pounds PsOs per acre.

' Received 100 pounds of nitrogen and 100 pounds PsOs per acre.

' Data from Hammons (9i).

' No-nitrogen plots produced an average of 57 pounds of oven-dry forage per

acre.

' No-nitrogen plots produced an average of 13.5 pounds of oven-dry forage

per acre.

Additional experiments in Mississippi by Jones

and coworkers {108) showed that summer grasses

responded about 2 weeks earlier to ammonium

nitrate than to anhydrous ammonia. The overall

total response to both sources of nitrogen, however, was the same. In these experiments, the

nitrogen was applied to permanent pasture sods

by broadcasting ammonium nitrate and by injecting ammonia 5 inches deep.

Ammonia, even in dilute water solutions, is

unsuitable for topdressing grassland. Pratt and

O'Brien (155) found that surface applications of

a l-to-9 dilution of ammonia liquor supplying 50 to

150 pounds of nitrogen jjer acre yellowed the grass

and retarded early spring growth of permanent

pastures. Similar results were observed by Bear

{3.Í) when solutions containing 100, 200, 300, and

400 pounds of aqua ammonia (2(^.7 percent) in

200 gallons of water were applied per acre to the

surface of grassland.
34 AGRICULTURE HANDBOOK 19 8, U.S. DEPARTMENT OF AGRICULTURE

More recently, Jameson {106) has conducted

field studies on the effects of a number of liquid

fertilizers on grassland in England. The dry-matter yields obtained with anhydrous ammonia,

ammonia liquor (24.6 percent N), solution "32"

(comparable to NP-13, table 5), solution "S"

(26.0 percent ammonia and 26.0 percent urea=33.5

percent N) were compared with those obtained

with ammonium sulfate (20.6 percent N) and

nitro-chalk (15.5 percent N). The liquids were

injected 2 to 4 inches deep and the solid fertilizers

were broadcast. Little significant difference was

observed among the yields with the liquid fertilizers. These yields, however, were generally

lower than those obtained with the conventional

solid fertilizers.

Rice

Wyche, Cheaney, and Moncrief {202) studied

the rice responses obtained in Texas from anhydrous ammonia and ammonium sulfate applied

at different times. Basal applications or 40

pounds of phosphoric oxide per acre were made

on each plot, and the nitrogen carriers were applied at the rate of 80 pounds of nitrogen per

acre. The results are given in table 34. Anhydrous ammonia was fully as satisfactory as ammonium sulfate when used as a preplant application, except when added in flooding water prior

to muddying up for planting. Ammonium sulfate

gave better yields than anhydrous ammonia when

the nitrogen was applied after planting.

In California, Mikkelsen {IjO) found that 30

pounds of nitrogen per acre drilled into Stockton

clay in the form of anhydrous ammonia gave significantly larger yields of rice than the same

quantity of nitrogen broadcast in the form of amTABLE 34.—Effect of method and time of application of

anhydrous ammonia and ammonium sulfate on rice

production in Texas ^

Yield of rice per acre '

Method and time oí application

Anhydrous

ammonia '

Ammonium

sulfate '

Fertilizers applied to drill-planted rice in dry soil:

In the soil just prior to planting.

Barrels

29,66

23.84

21.67

20.69

22.04

20.79

26.84

17.85

26.14

26.76

Barrels

28.27

Ammonium sulfate on top ofsoil just before flush

and ammonia in flushing water 26.02

On shallow-flooded field—

4 weeks after planting 23.49

8 weeks after planting , 24.12

On field with full flood—

24.60

8 weeks after planting 23.63

Fertilizers applied to water-planted rice, using

soaked seed:

In soil prior to flooding for water planting.

In flooding water prior to muddymg-up for

Dlanting

22.78

24.07

monium sulfate, cyanamide, or urea. Rice yields

obtained with anhydrous ammonia were the same

for application rates of both 30 and 60 pounds of

nitrogen per acre and were smaller for rates of

90 pounds. Yield reduction at the highest rate of

application was caused by delayed crop maturity.

The other nitrogen carriers produced increased

yields with each additional increment of nitrogen.

The work of Beacher {33) in Arkansas showed

that rice yields were greater from 60 pounds of

ammonia injected into the soil than yields from

an equivalent amount of nitrogen as solid ammonia nitrate used as a topdressing.

Oats and Barley

Andrews and coworkers {27) have shown that

the relative efficiencies of anhydrous ammonia and

solid ammonium nitrate for the production of oats

for grain in Mississippi is dependent on both the

time of application and the character of the soil.

Fall-applied ammonium nitrate was a poor source

of nitrogen in comparison to fall-applied anhydrous ammonia or to spring-applied ammonium

nitrate. On the more acid soils, ammonia applied

in the fall was superior to spring-applied ammonium nitrate. The reverse was true when the

soil pH was more than 5.5. Little difference in

the forage yields was obtained with split applications of anhydrous ammonia or amonium nitrate.

A single application of either nitrogen carrier in

September was as effective as the split application

made in September and December. A March application of nitrogen was necessary to produce

grain after grazing the oats.

Additional experiments in Mississppi {28) show

that water solutions of ammonium nitrate sprayed

on oats produced larger grain yields than surface

applications of solid ammonium nitrate. Poor

responses were obtained when either form of ammonium nitrate was applied late in the growing

season. Some results of these tests are given in

table 35.

Jones and Caldwell {107) found anhydrous ammonia and solid ammonium nitrate were effective

sources of nitrogen for oats and barley grown

under Minnesota conditions. The two nitrogen

carriers were applied several days before planting

TABLE 35.—Oat responses to applications of solution and

solid forms of amm,onium nitrate ^

' Liatafrom V. y(-hi?, Cheaney, and Moncrief (ÍOÍ).

' Yields without riiti o',^n were 16,16 barrels per acre for rice drill-planted in

7.^°",?°i^ ^''•^ '0'' tlie i'. ^ter-Dlanted rice. Applied at the rate of 80 pounds of nitrogen per acre.

Location and time of application Check

Form of ammonltmi

lütrate '

Solution Solid

State CoUege, Miss.:

March 8 and 9 . .

Bushels per

acre

27.9

34.0

27.1

17.2

Bushels per

acre

48.3

60.1

37.9

42.9

Bushels per

acre

41.6

March 31 66.4

April 12 30.0

New Hope, Miss.:

March 16 41,6

I Data from Andrews, Welch, and Beckett (ÍS).

' Application rate: 40 pounds oí nitrogen per acre.
LIQUID NITKOGEN FERTILIZERS FOR DIRECT APPLICATION 35

at a rate of 40 pounds of nitrogen per acre. The

fields had received blanket apphcations ot phosphorus and potassium. Average yields of 81.5

bushels per acre were produced by anhydrous

ammonia injected 4 to 5 inches below the surface

of the soil. A broadcast application of ammonium nitrate produced average yields of 83.1 bushels per acre. Yields on the check plots averaged

67.8 bushels. An experiment with barley gave

corresponding yields of 48.5, 44.2, and 31.8 bushels

per acre.

In Russia Byczkowski and coworkers {66, 66)

observed that the yields of oats and barley produced by applications of anhydrous ammonia,

aqua ammonia, ammonium nitrate, sodium nitrate, and an ammoniating solution containing

16.3 percent ammonium nitrate-nitrogen and 13.8

percent ammonia-nitrogen in water were generally

similar.

Wheat

As pointed out previously (table 25), anhydrous

ammonia and ammonium nitrate were equally

effective in promoting the growth of winter wheat

in Nebraska, particularly when applied in the

fall. Comparable results were observed in Kansas

where Smith {175) obtained almost identical increases in wheat yields from the use of anhydrous

ammonia, an ammoniating solution (LP-2), and

ammonium nitrate applied at a rate of 60 pounds

of nitrogen per acre. The two liquid nitrogen

carriers were injected into the soil, and the solid

ammonium nitrate was applied by means of a

fertilizer attachment on a grain drill.

One of the few experiments using an ammoniating solution as a source of nitrogen was conducted

by Hanway and coworkers {96) on two silty clay

loams in Nebraska. A comparison was made of

the effects of anhydrous ammonia, an ammoniating

solution (LP-6), ammonium nitrate, and ammonium sulfate on wheat production. The two liquids were applied 3 to 4 inches beneath the surface of the soil, and the solids were applied with a

combination fertilizer-grain drill. Results (table

36) show that a fall application of 30 pounds of

nitrogen per acre in the form of anhydrous ammonia gave larger yields than equivalent amounts

of ammonium nitrate or ammoniating solution.

No significant differences in yields were obtained

with any of the nitrogen carriers applied at 60

pounds of nitrogen per acre. Early spring application of the ammoniating solution was not so

effective as the solid nitrogen carriers on the

Waukesha soil ; there was no significant differences

on the Sharpsburg soil. Protein content of the

grain varied with both the rate and time of application of nitrogen.

Sugarcane

The efficiency of different nitrogen carriers in

sugarcane and sugar production has been investigated by Davidson {68). Some of the results are

TABLE 36.—Influence of rate and time of application of

various nitrogen carriers on ivheat production in

Nebraska '

Quantity

of nitrogen

applied

per acre

Soil type

Source of nitrogen and time

oí application

Waukesha silty

clay loam

Sharpsburg silty

clay loam

Yield

per acre

Protein

coûtent

Yield

per acre

Protein

content

Check

Pounds

0

30

30

30

60

60

60

30

60

30

30

30

60

60

60

Bushels

37.2

47.4

49.3

52.8

51.6

51.5

62.6

47.2

50.0

63.2

40.0

50.2

52.7

47.8

52.9

Percent

9.6

10.7

10.9

10.8

11.1

12.2

12.2

10.5

11.2

11.9

11.1

12.4

14.0

12.2

13.1

Bushels

34.3

43.8

43.7

45.5

51.7

49.9

51.9

43.8

44.7

45.1

45.5

41.5

46.9

49,0

44.2

Percent

10.6

Planting time:

.Ammonium nitrate

Ammoniating solution 3...

Anhydrous ammonia

Ammonium nitrate _ _

Ammoniating solution '...

Anhydrous ammonia

Early December:

Ammonium nitrate _

Do

Early spring:

Ammonium nitrate

Ammoniating solution '...

Ammonium sulfate—

Ammonium nitrate

Ammoniating solution '...

Ammonium sulfate

10.4

10.7

10.8

12.0

12.6

14.3

10.8

10.7

12.2

11.6

10.8

12.8

12.5

11.1

1 Data from Hanway, Luebs, and Rhoades (95); superphosphate was

applied to aU plots at the rate ot 40 pounds of PjOj per acre.

' Solution LP-6, table 5.

given in table 37. Sources of phosphorus and

potassium were not used in these experiments, as

these nutrients have a negligible influence on cane

production in the alluvial soils of Louisiana. The

nitrogen was applied during March and April and

the crop was harvested from late October through

November. Nitrogen applications increased the

yields of cane and sugar, but the differences due

to the various sources of nitrogen were not significant. Subsequent experiments {69) confirmed

the earlier results.

Further inforaiation on the comparative value

of a number of nitrogen carriers is supplied by

De Ment and Sturgis {73). Solid nitrogen carriers were mixed with superphosphate and potassium chloride and applied in the off-bar furrow

of stubble cane and covered immediately by the

TABLE 37.—Comparisons

stuhlle sugarcane on

of sources of ni

two soil types

trogen for firstin Louisiana"^

Quantity

of nitrogen

appUed

per acre

Mahoon silt loam

to very fine

sandy loam

Baldwin silt loam

Source of material

Cane

yield

Indicated

available

96° sugar

at

harvest

Cane

yield

Indicated

available

96° sugar

at

harvest

Pounds

72

35

64

72

100

35

64

72

100

Tons per

acre

Pounds

per acre

Tons per

acre

33.62

Pounds

per acre

7,538

Aqua ammonia 20.67

22.61

5,173

5,733

31.45 7,215

25.60

19.41

23.68

6,514

4,865

5,922

31.29 7,074

25. 09

15 3i

6,364

Check.... 21.11 4,638

' Data from Davidson (68).
36 AGRICULTURE HANDBOOK 198, U.S. DEPARTMENT OF AGRICULTURE

first dirting. Anhydrous ammonia was injected

below the superphosphate and potassimn chloride.

Fertilizer grade urea and ammoniiun sulfate gave

significantly larger yields of sugarcane and sugar

on a neutral clay loam than calcium cyanamide,

but they were no better than ammonium nitrate,

sodium nitrate, or anhydrous ammonia. All

sources of nitrogen tested were equally efl^ective on

a silt loam with a pH of 6.2.

Li (Íi5, 120) fomid no significant difi'erences

in the sugar yields obtained with different sources

of nitrogen applied to various soil types under

Taiwan conditions. Nitrogen sources included anhydrous ammonia, aqua ammonia, and solution

LP-2 applied below the surface of the soil and

ammonium sulfate, calcium cyanamide, and calcium ammonium nitrate applied in the customary

manner. On the other hand, sugarcane yields in

Jamaica [100] showed that aqua ammonia injected at depths of approximately 6 inches in the

soil is only about 70 percent as effective as ammonium sulfate broadcast. The difference was attributed to ineffective sealing of the ammonia in the

soil.

ECONOMIC CONSIDERATIONS

The cost of producing anhydrous ammonia is

less than that of any other synthetic nitrogen fertilizer, as it is one of the raw materials required in

nitrogen fertilizer manufacture. More processing

is required for the preparation and packaging of

solid forms of nitrogen from anhydrous ammonia

than for the preparation in marketable form of

other liquids therefrom. These differences in processing, transportation, and handling requirements

are reflected by market quotations that are appreciably lower on the basis of nitrogen content for

liquid nitrogen materials than for the solid products, as shown by the data in table 38 {9).

The cost of the nitrogen applied to the soil

rather than its f.o.b. price is of prime importance

to the farmer. This cost includes f.o.b. price,

freight and handling charges, cost of storage, a

reasonable dealer markup, and cost of application.

Location and type of farming area will have a

bearing on the relative costs to the farmer of the

liquid and solid forms of nitrogen.

Bowen, Ferg-uson, and Pierce US) developed

the data shown in figure 17 on North Carolina

costs of top- or side-dressing liquid and solid

forms of nitrogen at a rate of 60 pounds of nitrogen per acre. A custom application charge of 15

cents per pound of liquid nitrogen fertilizer was

used and basic costs of 11 and 15 cents per pound

of nitrogen were assumed for the liquid and solid

forms, respectively.

TABLE 38.—F.o.b. prices of chemical nitrogen fertilizers.

May 30, 1960 ^

Material Price per

ton

Price per

pound N

Ammonia, anhydrous, fertilizer, tanks, works,

freight equalized, east of Rockies

Ammonia, aqueous, 29.4 percent, tanks, works,

anhydrous basis, east of Rockies

Ammonium nitrate, domestic, fertilizer grade,

33.5 percent N, bags, f.o.b. works

Ammonium sulfate, standard granular, bulk,

f.o.b. works, base price

Nitrogen solutions, tanks, freight equalized,

N unit - -

Dollars

88.00

91.00

68.00

32.00

2 1.28

48.00

103.00,

Cents

5.3

5.4

10.1

7.6

6.4

Sodium nitrate, domestic, crude, bulk, carlots,

works ~ - - 14.8

Urea, 45 percent N, agricultural, bags, carlots,

(30 tons) delivered. East 11.4

Figure 17 shows that imder these conditions

custom-applied liquid nitrogen fertilizer is more

economical than solid nitrogen fertilizer applied

by the farmer. Twelve acres is the break-even

point for the costs of liquid nitrogen fertilizer

applied by the farmer with equipment costing

$100 versus the costs of farmer-applied solid nitrogen fertilizer ; 23 acres if the equipment costs $200.

The break-even acreages for liquid nitrogen fertilizer custom-applied versus farmer-applied with

$100 and $200 equipment are 17 and 31 acres,

respectively.

Data developed by Gaines and Crowe (89),

given in table 39, show that 56 pounds of nitrogen

per acre, derived either from anhydrous ammonia

or ammonium nitrate, can be applied to 50 acres

of cropland for 13.6 cents per pound. Anhydrous

ammonia would have an economic advantage with

the fertilization of larger acreages, the use of

higher rates of application, or a combination of

the two conditions. Under 1949 price relationships, 56 pounds of nitrogen per acre in the form

of anhydrous ammonia could be applied to 850

acres for 10.2 cents per pound of nitrogen. The

corresponding cost of nitrogen in the form of

ammonium nitrate would be 12.9 cents. The purchase prices of the ammonia and the ammonium

nitrate constituted 86 and 90 percent, respectively,

I Data from Oil, Painf, rind Drug Reporter (9).

Price per unit of 20 pounds of nitrogen.

FIGURE 17.—Cost of applied nitrogen per fertilized acre in

North Carolina, Bowen and coworkers (48).
LIQUID NITROGEN FERTILIZERS FOR DIRECT APPLICATION 37

of the total applied cost. The total cost for custom application of anhydrous ammonia at the rate

of 100 pounds of nitrogen per acre was estimated

as only slightly more ($0.30) _ than the purchase

price of the equivalent ammonium nitrate.

TABLE 39.—Cost of using anhydrous ammonia ana ammonium nitrate at an average rate of 56 'pounds of nitrogen

per acre on 50 acres of Mississippi cropland at 1949

prices ^

Items ot cost

Storage and handling.

Application

Material

Total costs.

Cost per acre

Cost per pound of N..

."^.nhydrouí

ammonia

$62.49

71.27

245. 50

380. 26

7.60

.136

Ammonium nitrate

$9.33

44.08

327. 25

380. 66

7.61

.136

1 Data from Gaines and Crowe (.89).

Heady and Baum {96) compared the cost of

farmer-applied solid and liquid forms of nitrogen

fertilizer in northern Iowa on the basis of 1956

prices. The study was based on fixed costs associated with the application equipment and storage facilities and such variable costs as tlie acreage

fertilized, rate of fertilization, cost of fertilizer,

labor, and tractor power.

Figure 18 shows tlie total cost per acre of applyiag liquid and solid nitrogen fertilizers at a rate

of 50 pounds of nitrogen per acre. A farmer with

a 5-row applicator and a 550-gallon storage tank

applied 61 pounds of ammonia (50 pounds N)

per acre on approximately 56 acres as economically

as the same amount of a solid source of nitrogen

was applied with a 12-foot distributor. The cost

of applied ammonia per acre was less than the

cost of solid fertilizer when applied on more than

56 acres or at higher rates of application. It was

more when applied on less than 56 acres or at

lower rates than 50 pounds nitrogen per acre.

The break-even acreage for a farmer without a

storage tank was about 30 acres. Break-even

acreages for the farmer using nonpressure and

low-pressure solutions were approximately 185

acres if he had no storage tank, and 260 acres if

he had a 550-gallon storage tank.

At a nitrogen application rate of 100 pounds

_ 10

Q- 8

'

Anhydrous ammonio

I

(1) 5-row applicator without storoge Tank

(2) 5-row applicator with 550 gal storoge tonk

(3) custom applicotion

\ Non - and low-pressure nitrogen solutions

\

(4) 5-row applicotion without storage tank

\ (5) 5-row applicotion with 550 gal. storage tank

\ (6) custom application

I \ Solid nitrogen materiols

(7) 12 - foot distributor

A V(5)

v, \ s

.,

:^^ - - -

--..._

40 120 200 260 360 440 520 600

Acres fertilized

DN-1951

FiGUEE 18.—Total cost per acre of applying 50 pounds of

nitrogen in liquid and solid forms.

per acre, anhydrous ammonia was applied for

less per acre than solid nitrogen materials even on

small acreages. This high application rate lowers

the break-even acreages for nonpressure and lowpressure solutions to 50 acres if the farmer has no

tank and to 80 acres if a 550-gallon storage tank

has been purchased.

Custom application for anhydrous ammonia

was 90 cents per acre less than for nitrogen solution. Nitrogen solutions can be custom-applied on

a small acreage at rates of 50 pounds of nitrogen

per acre at a lower cost than the solid form can

be applied with farmer-owned equipment. Custom application of liquids was much less expensive

than farmer application of solid materials wlien

100 pounds of nitrogen were applied per acre. At

this rate of application, average custom costs

per acre for anhydrous ammonia were less than

the cost of farmer application up to about 120

acres. A comparable figure for the nonpressure

and low-pressure solutions was about 320 acres.

LITERATURE CITED

(1) ANONYMOUS.

1937. PURE AMMONIA IN IRRIGATION. Amer. Fert.

87 (3) : 10-11.

(2)

1953. AMMONIA TO HAWAII. Chem. Week 73 (25) :

48.

(3)

(4)

1954. AMMONIA SHIPMENT BY WATER PL.AN OF

SHELL CHEMICAL CO. Oil, Paint, and Drug

Rptr. 165 (3) : 38.

10554 ENTEK : AQUA AMMONIA. Chem. Engin.

News 32 : 1456-1457, lllus.

(5)

(6)

(7)

(S)

1954. HANDBOOK FOR LIQUID NITROGEN KIT. 22 pp.

G. L. F. Soil Building Service, Ithaca, N.Y.

1955. AMMONIA FACILITTES NEARINQ COMPLETION,

MID-SOUTH SAYS. Oil. Paint, and Drug

Rptr. 167 (2) : .56.

1955. NEW TBAN SPORT-STORAGE SYSTEM FOR AMMONIA BEGUN BY SHELL. AgT. Ammonia

News 5 (1) : 54, illus.

1938. SOLUTION CODING SYSTEM VOTED BY IFDU8TBY

GROUP. Farm Chem. 121 (10) : 51.
38 AGRICULTURE HANDBOOK 198, U.S. DEPARTMENT OF AGRICULTURE

(9)

(10)

(11)

(12)

(13)

(14)

(15)

(16)

(17)

(18)

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(20)

(21)

(22)

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(26)

(27)

ANONYMOUS.

1960. CUERENT MARKET QUOTATIONS. Oil, Paint,

and Drug Bptr. 177 (23) : 12-16, 18-33.

ADAMS, J. B.

1957. DIRECT APPLICATION NHJ CONTINUES RISE.

Agr. Ammonia News 7 (5) : 13, 42, illus.

1957. PHYSICAL AND CHEMICAL CHARACTERISTICS

OF COMMERCIAL NITROGEN SOLUTIONS FOR FEaiTiLizER USE. Assoc. Amer. Fert. Control

Off., Off. Pub. 11: 66-69H [12 pp.].

1960. ANHYDROUS AMMONIA—DOMESTIC PRODUCTIVE CAPACITY AND CONSUMPTION AS A FERTILIZER MATERIAL. AgF. Ammoiüa News 10

(1) : 23, 25, 43, illus.

and SoHOLL, W.

1957. NITROGEN FERTILIZER MATERIALS FOE DIRECT

APPLICATION. Com. Fert. 94 (1) : 27, 30,

32-34, 36, iUus.

and SCHOLL, W.

1958. MATERIALS USED IN THE MANUFACTURE OF

MIXED FERTILIZER IN CONTINENTAL UNITED

STATES. Assoc. Amer. Fert. Control Off.,

Off. Pub. 12 : 63-74, illus.

AGRICULTURAL AMMONIA INSTITUTE.

1959. OPERATIONAL SAFETY MANUAL FOR ANHYDROUS AMMONIA. 20 pp., illus. Agricultural Ammonia Institute, Memphis, Term.

ALDRICH, D. G., BOSWELL, S. B., ZINK, F. W., and

others.

1953. FERTILIZER STUDIES WITH NITRIC ACID AND

NITROGEN DIOXIDE. Cltrus Leaves 33 (2) :

26, 28, 32.

ALLISON, F. B.

1958. FIXED AMMONIA IN SOILS AND ITS AVAILABILITY TO CROPS. Agr. Ammonia News 8

(6) : 19-20, 43.

KEFAUVER, M., and EOLLER, E. M.

1953. AMMONIUM FIXATION IN SOILS. Soil Sci.

Soc. Amer. Pro<?. 17: 106-110.

AMERICAN SOCIETY OF MECHANICAL ENGINEEES.

1952. API-A.S.M.E. CODE FOR UNFIRED PRESSURE

VESSELS. 1951 edition, 290 pp., illus.

ANDERSON, O. E., and PURVIS, E. R.

1954. ANHYDROUS AMMONIA RESEARCH IN NEW

JERSEY. Agr. Ammonia News 4 (2) : 18,

20, &4, 58, illus.

and PURVIS, E. B.

1955. EFFECTS OF LOW TEMPERATURES ON NITRIFICATION OF AMMONIA IN SOILS. Soll Sci. 80:

313-318, illus.

ANDREWS, W. B.

1947. THE USE OF ANHYDROUS AMMONIA AS A

SOURCE OF NITROGEN (IN SOILS). Amer.

Fert. 107 (12) : 9-10, 28; (13) : 11, 24-26,

28, illus.

1953. APPLY ANHYDROUS AMMONIA WHEN PLANTS

NEED NITROGEN. Mlss. AgT. Bxpt. Sta.

Inform. Sheet 48.5, 2 pp.

1956. ANHYDROUS AMMONIA AS A NITROGENOUS

FERTILIZER. In Norman, A. G., ed. Advances in Agronomy 3: 61-125, illus.

Academic Pre.ss Inc., New York.

EDWAEDS, F. E., and HAMMONS, J. G.

1947. AMMONIA AS A SOURCE OF NITEOGEN. Miss.

Agr. Expt. Sta. Bui. 448, 21 pp., illus;

revised as Miss. Agr. Expt. Sta. Bui. 451,

.34pp. illus.: (1948).

EDWAEDS, F. E., and HAMMONS, J. G.

1947. AMMONIA AS A SOUECE OF NITROGEN. Sugar

Jour. 3: 5-8.

NEELY, J. A. and EDWARDS, F. B.

1951. ANHYDROUS AMMONIA AS A SOUECE OF NITROGEN. Miss. Agr. Expt. Sta. Bui. 482, 39

pp., illus.

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WELCH, G. B., and BECKETT, J. W.

1952. EESEAECH ON USE OF AMMONIUM NITBATB

SOLUTION. Miss. Farm Res. 15 (2) : 1,

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1954. COMPARABLE COTTON YIELDS. Agr. Ammonia

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1953. COMMERCIAL FERTILIZERS FOE WINTER WHEAT

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1957. TRUCKING COMPRESSED GASES. AgT. Ammonia News 7(1): 38-42, illus.

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1956. CORROSION OF METALS BT LIQUID FERTILIZER

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44 AGRICULTURE HANDBOOK 198, U.S. DEPARTMENT OP AGRICULTURE

APPENDIX

state agencies having jurisdiction over the storage and handling of liquid nitrogen fertilizers

State Agency and location

Alabama Division of Agricultural Chemistry,

Department of Agriculture and

Industries, State Office Bldg.,

P.O. Box 220, Montgomery.

Alaska Commissioner, Department of

Commerce, P.O. Box 22.59,

Juneau.

Arizona Corporation Commission, Capitol

Annex, Phoenix.

Arkansas Boiler Inspection Division, State

Labor Department, A. E. A.

Building, Capitol Grounds, Little

Rock.

California, Division of Industrial Safety, Department of Industrial Relations,

965 Mission St., San Francisco 3.

Colorado

Connecticut Department of State Police, 100

Washington St., Hartford 1.

Delaware

Florida Fire Marshal (storage and handling) ; Florida Railroad and Public

Utilities Commission (transportation), Tallahassee.

Georgia Safety Fire Commissioner, Atlanta

3.

Hawaii Bureau of Industrial Hygiene, Department of Health, Honolulu.

Idaho Division of Commercial Feed and

Fertilizer, Department of Agriculture, 206 State House, Boise.

Illinois Division of Foods, Dairies and

Standards, Department of Agriculture, 160 North LaSalle St.,

Chicago I.

Indiana Fire Marshal, State House, Indianapolis.

Iowa Department of Public Safety, Des

Moines 19.

Kansas State Board of Agriculture, State

Office Building, Topeka.

Kentucky. _ Department of Agriculture, Labor

and Statistics, Capitol Annex,

Frankfort.

Louisiana Anhydrous Ammonia Commis.sion

of Louisiana, Box 4261, Capitol

Station, Baton Rouge 4.

Maine Department of Agriculture, Augusta.

Maryland

Massachusetts

Michigan Chemical Laboratories Division,

Michigan Department of Agriculture, 1615 South Harrison Rd.,

East Lansing.

Minnesota Safety and Accident Division, Labor and Industry Department,

137 State Office Bldg., St. Paul 1,

State Agency and location

Mississippi- Motor Vehicle Comptroller, Jackson.

Missouri. Industrial Inspection, Labor and

Industrial Relations Department,

221 West High St., Jefferson

City.

Montana

Nebraska

Nevada

New Hampshire

New Jersey Bureau of Engineering and Safety,

Department of Labor and Industry, 29 East Front St.,

Trenton.

New Mexico Border Inspector, New Mexico

Cooperation Commission, Santa

Fe.

New York

North Carolina Weights and Measures Division,

North Carolina Department of

Agriculture, Raleigh.

North Dakota

Ohio Industrial Relations Department,

State Office Bldg., Columbus.

Oklahoma Seed, Feed and Fertilizer Division,

Oklahoma State Board of Agriculture, 122 Capitol Bldg., Oklahoma City.

Oregon Bureau of Labor, 325 State Office

Bldg., Salem.

Pennsylvania Bureau of Inspection, Pennsylvania

Department of Labor and Industry, Harrisburg.

Rhode Island Industrial Inspection Division,

Rhode Island Department of

Labor, 83 Park St., Providence.

South Carolina Department of Fertilizer Inspection

and Analysis, Clemson.

South Dakota

Tennessee Division of Feeds, Seeds, and

Fertilizers, 411 State Office Bldg.,

Nashville.

Texas _

Utah

Vermont Vermont Agricultural Experiment

Station, Burlington.

Virginia Transportation Division, State corporation Commission, Blanton

Bldg., Richmond.

Washington

West Virginia Department of Agriculture,

Charleston 5.

Wisconsin Industrial Safety and Buildings

Division, Industrial Commission,

Room 234, State OflSce Bldg.,

Madison.

Wyoming State Chemist and Director, Chemical and Bacteriological Laboratory, Box 656, Laramie,

U.S. GOVERNMENT PRINTING OFFICE: 1961 O—586670
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