Experiments on the Utilization of Nitrogen in Fertilizer Materials

.

T H E JOURNAL OF INDUSTRIAL AND ENGINEERING C H E M I S T R Y VOL.

JULY, 1909.

I.

No. 7

THEJ O U R N A L O F I N D U S T R I A Lthey are applied, while materials like ground leather are designated as slightly available because AND E N G I N E E R I N CG HEMISTR Y yield but little nitrogen under the same conthey PUBLISHED BY

THE AMERICAN CHEMICAL, SOCIETY. BOARD O F EDITORS. Editor : W. D. Richardson. Associate Ediiovs: Geo. P. Adamson, E. G. Bailey, G. E. Barton, Wm. Brady, Wm. Campbell, F. B . Carpenter, Virgil Coblentz, Francis I. Dupont, W. C. Ebaugh, Wm. C. Geer, W. F. Hillebrand, W. D. Horne, L. P. Kinnicutt, A. E. Leach, Karl Langenbeck, A . D. Little, P. C. McIlhiney, E. B. McCready, Wm. McMurtrie, J. Merritt Matthews, T.J . Parker, J. D. Pennock, Clifford Richardson, Geo. C. Stone, F. W. Traphagen, Ernst Twitchell, Robt. Wahl, Wm. H. Walker, M . C. Whitaker, W. R . Whitney. Subscription price to non-members of the American Chemical Society f6.m yearly.

Published monthly.

Copyright, 1909,by W. D . Richardson, Edffor.

VOl.

JULY, 1909.

1.

No. 7 ~

ORIGINAL PAPERS -__.

EXPERIMENTS ON THE UTILIZATION OF NITROGEN IN FERTILIZER MATERIALS. By

EDWARDB. VOORHEESAND

JACOB

G. LIPMAN.

Received M a y 1, 1909.

Nitrogenous fertilizers possess an agricultural value that is far from constant. A larger or smaller proportion of the nitrogen applied may be returned in the crop, the returns being directly affected by the character of the soil, of the season, and of the crop itself. Rut while there is a very considerable range of variation in the returns from a given quantity of nitrogenous substance a more or less definite relation still persists that enables us to classify nitrogenous materials according to their availability, that is, according to the readiness with which they may be transformed into plant-tissue. Materials like sodium nitrate are designated as readily available because a large proportion of their nitrogen is returned in the crop to which

ditions. The entire question of availability, particularly in its relation to nitrogenous fertilizers, is one of extreme importance in all sections where fertilizers are used. Yet, notwithstanding its importance, it is scarcely appreciated by the average user of commercial fertilizers. To him quantity is the only desideratum and he does not inquire as to the source of the nitrogen in the mixed goods that he purchases. On the other hand, the manufacturers of fertilizers are well aware of the comparatively high availability of materials like sodium nitrate, ammonium sulphate, or calciurri cyanamid. But they are forced to harmonize as best as they can the conflicting relations between agricultural and commercial values. They realize that these values do not run parallel to one another, since the less readily available forms of plant-food are not always the cheapest, nor the more readily available forms the dearest. But apart from commercial fertilizers, the availability of nitrogen compounds is a matter that concerns all farmers. Animal manures used so extensively on arable soils show a wide range of availability under varying conditions, and the same holds good with leguniinous or non-leguminous green manures. We cannot always account for the variations in availability even though we recognize the composition of the nitrogenous materials, and the character of season, crop and soil as contributing factors. I t will not be disputed, however, that in view of the vast economic significance of the nitrogen question in agriculture, a clearer understanding of the factors affecting the availability of nitrogenous fertilizers is highly desirable. I t is hoped that the experiments reported in the following pages may serve as a contribution towards the better understanding of availability and its underlying causes. METHODS EMPLOYED.

The experiments under consideration were car. ried out in large galvanized iron cylinders 4 fee long and 23.5 inches in diameter, open at bot1

398

T H E JOURNAL OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y . July, 1909

ends. After being carefully painted both inside and outside the cylinders were sunk into holes dug for the purpose until the upper rim projected about 2 inches above the level of the surrounding soil. The carefully mixed gravelly subsoil was then placed in the cylinders and packed up to about The subsoil was covered in IO inches of the top. each case with weighed quantities of soil which formed a layer of about 8 inches in depth. There were secured in this manner sixty small plats containing soil and subsoil of identical composition. In each case the contents of the cylinder were isolated from the adjoining soil to a depth sufficient to exclude external influences. The sixty cylinders were divided into twenty series of three plats each, representing twenty different systems of nitrogen treatment. The three soils in each series received the same treatment, allowing thus a more perfect equalization of experimental error. The surface soil selected for the experiment corresponds to the type designated in the survey work of the Bureau of Soils as Penn Loam.' A sample from the vicinity of New Brunswick examined by the Bureau of Soils was found to possess the following mechanical composition : Mm. to Organic matter.. Gravel. 2.000 Coarse sand.. 1.000 Medium sand.. . . . . . . . . . 0.500 Fine sand. 0.250 Very fine sand.. ........ 0.100 Silt 0.050 Clay .................. 0.005

............

................ .......... ............. ...................

Mm.

Per cent.

1 .oooo

3.40

0 ,5000 0.2500 0.1000 0.0500

0.0050

7.20 4.50 7.58 5.04 41.62

0.0001

29.62

......

1.38

This soil type represents a large area in the state and is well adapted for the growth of cereals and grasses. A sufficiently large quantity of such soil was gathered in the neighborhood of the station from a field in which no crop had been grown for twenty years or more, and upon which no manure had been applied within the knowledge of those familiar with the land for a long time. In so far as native vegetation is concerned, it was practically barren, and it was supposed that the soil was very poor in nitrogen, and, therefore, well adapted for nitrogen studies. Subsequent analyses showed, however, that this soil was rich in nitrogen. As will be seen later, the comparatively large proportion of nitrogen did not prove detrimental to the satisfactory progress of the experiment. After sifting and thorough mixing, the soil was distributed in the several cylinders in carefully 1 Burke and Wilder, 4th Rep. Field Operations, Bur. Soils, U. S. Dept. A n . , p . 163.

weighed portions each containing 180 pounds of air-dry soil. All soils in the sixty cylinders received a liberal allowance of lime, and with the exception of those in Series I, they received also dressings of acid phosphate and of potassium chloride (muriate of potash) a t the rate of 640 pounds and 320 pounds per acre, respectively. The application of the phosphorus and potassium compounds has been renewed annually, for a period now of eleven years, with the purpose in view, primarily, of providing an excess of these constituents and of assuring to the nitrogen the r61e of the controlling factor in the development of the crops. I t may be readily seen, a t the same time, that such large applications of acid phosphate and of muriate would constitute a serious drain on the lime in the soil, which drain would be intensified still further in those series where manure, ammonium sulphate Series.

1. Check

A

...........................

0 0

......................... 3. Manure, solid, fresh ............... 4. Manure, solid and liquid, fresh ..... 3. Manure, solid, leached ............. 6. Manure, solid and liquid, leached.. .. 5. Sitrate of soda, 5 gms. ............ 8. Xitrate of soda, 10 gms. ........... 2. Minerals

9. Manure, solid, fresh: nitrate, 5 g m s . .

10. Manure, solid, fresh ; nitrate, 10 gms 11. Manure, solid and liquid, fresh; ritrate, 5 gms.

.................

12. Manure, solid and nitrate, 10 gms.

liquid,

fresh;

................

13. Manure, solid, leached: nitrate, 5

........................... gms. ........................... 13. Manure, solid and liquid, leached; nitrate, 5 gms. ................. gma.

14. Manure, solid. leached: nitrate, 10

1G. Manure. solid and liquid, leached; nitrate, 10 gms.

................

............. 18. Dried blood ....................... 10. Manure, solid, leached, sulphate of ammonia ...................... 17. Sulphate of ammonia

20. Manure, solid. leached ; dried blood

B

..

C

0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0

8

.

VOORHEES A N D L I P M A N ON NITROGEN I N F E R T I L I Z E R M A T E R I A L S .

399

and dried blood are applied. I t goes without lation of residual nitrogen. The third crop, oats, saying that the proportion of lime in the soil, as was followed by corn as the residual crop. The well as the rate of its removal, play a very essential fourth crop, wheat, had no residual crop grown part in the transformation of soil nitrogen, and, after it, but was followed directly by timothy. hence, in the economy of its utilization by the Two cuttings were made 0; the latter, the second crops. This point will be discussed more fully in cutting being regarded as the residual crop. The first rotation began in 1898 and ended in connection with the crop yields of 1908. The fertilizer and manure treatment for the dif- 1902. The three soils in each series were then ferent series is shown in the accompanying dia- thoroughly mixed in one heap in order to equalize slight differences that may have arisen in the gram. I t will be seen that nothing a t all was applied course of the rotation, and a third of this uniform in Series I , and only minerals, that is, acid phos- soil mixture was returned to each cylinder. The phate and muriate of potash, in Series 2 . The same procedure has been followed also in the second nitrogenous materials applied in Series 3-20 in rotation except that the second main crop, that is addition to the minerals, included sodium nitrate, the oats of 1904, was followed by corn instead of ammonium sulphate, dried blood, and four grades millet. The second rotation came to a n end in of cow manure: viz., solid excreta, fresh; solid and the fall of 1907. I n the spring of 1908, the several liquid excreta, fresh; solid excreta, leached; and soils were spaded up and ground limestone a t the solid and liquid excreta, leached. The nitrate rate of two tons per acre was applied in IB-ZOB was applied in two different quantities: in the one and IC-2oC, 1A-20A remaining unlimed. The macase a t the rate of 5 grams per cylinder, equivalent nures and fertilizers were then applied in the usual to 160 pounds per acre, and in the second a t the way and corn planted in all of the cylinders. The rate of I O grams per cylinder, equivalent to 320 succession of crops in the eleven seasons was therepounds per acre. The applications of ammonium fore as follows: sulphate and of dried blood contained quantities 1903 Corn 1895 Corn 1899 Oats (millet) 1904 Oats (corn) of nitrogen equivalent to that in the larger applica1900 Oats (corn) 1905 Oats (corn) tion of nitrate. Proper allowance was made for 1901 Wheat 1906 Wheat 1902 Timothy (two cuttings) 1907 Timothy (two cuttings). the slighter availability of the nitrogen in the ma1905 Corn. nure by applying quantities of the latter sufficient Of the eleven main crops and six residual crops to furnish about 4 grams of nitrogen, as compared (including the second cuttings of timothy) thus with the 0.78 gram in the 5 grams of nitrate, and harvested, only three will be considered here; the 1 . 5 5 grams in the I O grams of nitrate or in the namely, the corn crops of 1898, 1903, and 1908, ammonium sulphate and dried blood. respectively. The discussion of the analytical data At the end of each growing season, determinawill concern the yields of dry matter, the proportions were made of the actual dry matter in the tionate content of nitrogen in the dry matter, the different crops, of the proportion of nitrogen conyields of nitrogen, the proportion of nitrogen from tained in them, of the gain of nitrogen due to the the different materials recovered in the crop, and materials added, and of the per cent. of applied the relative availability of the nitrogen in the nitrogen recovered. The crops grown in the cyldifferent materials. The discussion will also coninder soils followed one another in regular rotation cern the influence of the lime applied in 1908 on and consisted of corn, oats, wheat and timothy. the yields and composition of the corn crop. These were the main crops. I n some instances TABLE RESULTS OF THE CORN EXPERIMENT, 1898. the main crops were followed by " residual" crops to which no further applications of manures or fertilizers were made. It was intended that these residual crops gather and lay fast in their tissues the available nitrogen that the main crops failed to take up and assimilate. 1 A .... 240.2 0.812 1.95 . . . . . . . . . . . . . . B .... 208.0 0.707 1.47 . . . . . . . . . . . . . . The corn which was the first crop in the rotation C .... 195.5 0.919 1.80 . . . . . . . . . . . . . . was not followed by a residual crop, the soil remain2 A .... 289.6 0.625 1.79 . . . . . . . . . . . . . . ing bare in the late fall and winter. The second B .... 253.9 0.527 1.44 . . . . . . . . . . . . . . crop, oats, was succeeded by millet for the accumuC .... 329.8 0.722 2.38 . . . . . . . . . . . . . .

T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y . TABLEII.-RESULTS

TABLEI-( Continued).

A%

"i

.-ui

2 3 A B C 4 A

B C S A

B C 6 A

B C 7 A

B C 8 A

B

C 9 A

B C 10 A

B C 11 A

B C 12

A B C

13 A

B C 14 A

B C 15 A

B C 16 A

B C 17 A

B C 18 A

B C 19 A

B C 20 A

B C

8" %j B .9

.E! 0'

,e

Y @

2"

B

a

51

Srri

.- e

.d

UG

;2

&

9" Ea8 2 Fb

UE

Ea

.I

C

P 0;

%%

e

At! C C

8%

Iw

@

t82

g

250

PlfiU

313.3 370.7

2.21 2.25 2.90

0.34 0.38 1.03

7.02 7.85 *21.28

5.40 5.40 5.40

475 .O 467.1 450.6

0.665 0.634 0.679

3.16 2.96 3.06

1.29 1.09 1.19

23.89 20.19 22.04

4.09 4.09 4.09

441.3 340.0 378.5

0.603 0.682 0.711

2.66 2.32 2.69

0.79 0.45 0.82

19.32 11.01 20.06

16.80

4.16 4.16 4.16

409.6 358.5 420.4

0.635 0.561 0.714

2.60 2.01 3 .OO

0.73 0.14 1.13

17.55 3.37 27.17

22.36

0.80 0.80 0.80

332.1 325.6 331.3

0.717 0.703 0.788

2.38 2.29 2.61

0.51 0.42 0.74

63.75 52 .SO 92.50

69.58

1.60 1.60 1.60

360.9 393.9 396.6

0.632 0.624 0.678

2.28 2.46 2.70

0.41 0.59 0.83

*25.63 36.88 51.88

44.38

5.64 5.64 5.64

356.4 343.2 388.1

0.558 0.653 0.776

1.99 2.24 3.01

0.12 0.37 1.14

2.13 6.57 20.22

6.44 6.44 6.44

389.5 394,2 405.8

0.657 0.629 0.823

2.56 2.48 3.34

0.69 0.61 1.47

10.73 9.49 *22 ,84

6.20 6.20 6.20

463.3 508.6 468.3

0.762 0.655 0.711

3.53 3.33 3.33

1.66 1.46 1.46

26.77 23.55 23.55

4.84 4.84 4.84

6s 323.2

*

1 A

B C

..... .....

22.04

2 A

B C

.....

.....

3 A

B C

.....

.....

4A

B C

.....

.....

5

C

.....

.....

6 A

B C

..... 9.64

..... ..... 10.11 ..... ..... 24.62

..... .....

A B

7 A

B C 8 A

B C 9 A

B

C

7.00 7.00 7.00

508.0 498.0 504.5

0.748 0.787 0.842

3.80 3.92 4.25

1.93 2.05 2.38

27.57 29.27 33.99

30.28

4.89 4.89 4.89

490.2 374.8 396.5

0.741 0.651 0.613

3.63 2.44 2.43

1.76 0.57 0.56

*35.99 11.66 11.45

11.56

.....

11 A

5.69 5.69 5.69

512.4 426.2 415.3

0.710 0,737 0.667

3.64 3.14 2.77

1.77 1.27 0.90

*31.11 22.32 15.82

..... 19.07 .....

12 A

.....

B C

4.96 4.96 4.96

391.2 359.0 384.7

0.721 0.591 0.749

2.82 2.12 2.88

0.95 0.25 1.01

*

19.15 5.04 20.36

5.76 5.76 5.76

361.7 385.7 419.0

0.868 0.954 0.697

3.14 3.68 2.92

1.27 1.81 1 .os

22.05 *31.42 18.23

1.65 1.65 1.65

387.8 401 .O 330.1

0.671 0.631 0,809

2.60 2.53 2.67

0.73 0.66 0.80

44.24 40.00 48.48

1.65 1.65 1.65

322.2 341.8 303.7

0.664 0.702 0.836

2.14 2.40 2.54

0.27 0.53 0.67

*19.15 37.59 47.52

5.74 5.74 5.74

408.6 439.2 442 .O

0.732 0.688 0.758

2.99 3.02 3.35

1.12 1.15 1.48

19.51 20.03 25.78

2.20 2.84 2.72

0.33 0.97 0.85

5.74 5.74 5.74

361.7 376.6 410.0

0.608 0.754 0.663

* Not included in the average.

CORN ExPBRIMBNT. 1903.

I

o c

Z-Qb 0.684 0.718 0.782

2%

OF

July, 1909

*

6.00 17.64 15.46

.....

10 A

B C

,....

B C

... . .... .... ... . .... ... .

51 81 81

1.632 0.941 1.113

0.832 0.762 0.902

163 148 170

0.616 0.607 0.630

1.004 0.898 1.071

Ave. (0,991)

.....

.... .... .. .. . . .. .... ....

4.00 4.00 4.00

205 217 202

0.647 0.673 0.629

1.326 1.460 1.271

0.335 0.469 0.280

8.4 11.7 7.0

3.99 3.99 3.99

351 315 321

0.524 0.541 0.594

1.839 1.704 1.907

0,848 0.713 0.916

21.3 17.9 23.0

3.97 3.97 3.97

262 267 273

0.537 0.554 0.629

1.407 1.479 1.717

0.416 0.488 0.726

10.5 12.3 18.3

13.7

4.00 4.00 4.00

238 265 249

0.655 0.594 0.664

1.559 1.574 1.653

0.568 0.583 0.662

14.2 14.6 16.6

15.1

0.78 0.78 0.78

186 189 215

0.656 0.609 0.633

1.220 1.151 1.361

0,229 0.160 0.370

29.4 20.5 *47.4

25.0

1.55 1.55 1.55

255 183 245

0.651 0.752 0.638

1.660 1.376 1.563

0.669 0.385 0.572

43.2 24.8 36.9

35.0

4.78 4.78 4.78

304 254 288

0.638 0.743 0.656

1.940 1.887 1.889

0,949 0,896 0.898

19.9 18.7 18.8

19.1

5.55 5.55 5.55

366 424 371

0.621 0.559 0.573

2.273 2.370 2.126

1.282 1.379 1.135

23.1 24.8 20.4

4.77 4.77 4.77

319 372 388

0.581 0.605 0.542

1.853 2.251 2.103

0.862 1.260 1.112

18.1 26.3 23.3

5.54 5.54 5.54

432 445 424

0.621 0,537 0.567

2.683 2.390 2.404

1.692 1.399 1.413

30.5 25.3 25.5

27.1

4.75 4.75 4.75

256 282 313

0.572 0.559 0.563

1.464 1.576 1.762

0.473 0.585 0.771

10.0 12.3 16.2

12.8

5.52 5.52 5.52

436 400 388

0.489 0.497 0.519

2.132 1.988 2.014

1.141 0.997 1.023

20.7 18.1 18.5

19.X

4.78 4.78 4.78

299 308 304

0.598 0.602 0.589

1.788 1.854 1.791

0.797 0.863 0.800

16.7 18.1 16.7

17.2

5.55 5.55 5.55

413 383 333

0.554 0.563 0.711

2.288 2.156 2.368

1.297 1.165 1.377

23.4 21.0 24.8

1.62 1.62 1.62

317 291 251

0.523 0.500 0.509

1.658 1.455 1.278

0.667 0.464 0.287

41.2 28.6 *17.7

.

19.76

.....

..... ..... ..... 44.24 ..... 20.14

..... 42.36

..... .....

13

A B C

14 A

B C 15 A

B C 16 A

21.77

B C

.....

17 A

.....

16.55

.....

B

C


.... 9.0 .... .... 20.7 ....

.... ....

....

....

.... .... ....

.... ....

.... . .. . 22.8 .... .... 22.6

....

.... ....

....

....

.... .... ....

.... .... 23.1 .... .... 34.9

....

VOORHEES A N D L I P M A N ON NITROGEN I N F E R T I L I Z E R M A T E R I A L S

401

T L B L B ~ [ [ - ( C o n f i n u eI ) .

TABLEII( C o n f i n u r d ) .

L

& 0'

M

e;

m'

$5

.3

eu

W

m

.....

18 A

B

1.55 1.55

216 225

0.566 0,614

1.223 1.382

0.232 0.391

15.0 25.2

5.59 5.59 5.59

405 412 378

0,523 0.492 0.523

2.118 2.027 1.977

1.127 1.036 0.986

20.2 18.5 17.6

18.8

5.52 5.52 5.52

355 321 354

0,570 0.535 0.547

2.024 1.717 1.936

1.033 0,726 0.945

18.7 13.2 17.1

16.3

C

19 A

B C

20 A

B C

2 A

B C

3 6

B C 4 A

B C 5 A

B C

6 A B

C 7 A

B

C 8 A B

C 9 A

B

C 10 A

B C

11

a B C

12 A

B C

13 A

B C

l6 A

B C

17 A

0.445 0.463

2.002 1.930

1.115 1.043

20.10 18.80

4.78 4,78 4.78

296 304 315

0,521

1.542 1,511 1.710

0.655 o.624 0.823

13.69 13.05 17.22

14.67

5.55 5.55 5.55

386 432 412

0,477 0,490

1'841 2.060 2.018

0'954 1.173 1.131

17'19 21.13 20.38

19.57

239 286 291

0,542 0 449 0 494

1.295 1.284 1.437

0.408 0.397 0.550

25.19 24.51 33.95

27.90

0,49f

0,543

0,477

I.

$:

C

1.62 1.62 1.62

E

LO

riM

18 A

1.57

182

0.597

1.086

0.199

12.68

@a

.g* cgi

B

4 .,E

1.57 1.57

228 245

0.580 0.580

1.322 1.421

0.435 0.534

27.71 34.01

.... .... .... ....

65 94 125

0.857 0.711 0.679

0.557 0.668 0.848

5.62 5.62 5.62

317 348 366

0.563 0,546 0,542

1.791' 1,900 1.983

0.904 1.013 1.096

16.10 18.02 19.50

150 169 176

0.547 0.528 0.540

0,820 0.892 0.950

5.57 5.57 5.57

248 300 346

0.563 0,606 0.580

1.397 1.818 2.006

0.510 0.931 1.119

9.15 16.71 20.10

4.00 4 .OO 4.00

224 263 248

0.558 0.543 0.536

1.249 1.428 1.329

0.362 0.541 0.442

9.05 13.52 11.05

4.00 4.00 4.00

340 326 373

0.441 0.482 0.455

1.499 1.571 1.697

0.612 0.684 0.810

15.30 17.10 20.25

17.55

4.00 4.00 4.00

236 249 289

0.528 0.540 0.514

1.246 1.344 1.485

0.359 0.457 0.598

8.97 11.42 14.95

11.77

4.00 4.00 4 .OO

254 259 278

0.482 0.477 0.569

1.224 1.235 1 .581

0,337 0.348 0.694

8.32 8.70 17.35

11.50

0.78 0.78 0.78

188 228 249

0.496 0.492 0.482

0.932 1.121 1.200

0.045 0.234 0.313

5.80 30.00 40.13

25.26

1.55 1.55 1.55

257 33 1 332

0.506 0.470 0.465

1.300 1.555 1.543

0.413 0.668 0.656

26.65 43.10 42.32

37.35

4.78 4.78 4.78

288 307 386

0.533 0.506 0.511

1.535 1.553 1.972

0.648 0.666 1.085

13.56 13.93 22.69

16.74

5.55 5.55 5.55

383 444 312

0.455 0.460 0.511

1.742 2.042 1.594

0,855 1.155 0.707

15.41 20.81 12.74

16.32

4.78 4.78 4.78

418 497 491

0.499 0.514 0.485

2.085 2.554 2.381

1.198 1.667 1.494

25.06 34.87 31.25

30.40

5.55 5.55 5.55

459 483 538

0.452 0.492 0.506

2.074 2.376 2.722

1.187 1.489 1.835

21.39 26.83 33.06

4.78 4.78 4.78

296 530 328

0.506 0.499 0.511

1.479 2.644 1.676

0.592 1.757 0.789

12.38 *36.76 16.51

.% Z Z

C

-

C

450 417

a

.-vi ;. B

....

15 A

5.55 5.55

sui

33

1 A

.... ....

B C

*-

$E x

.... ....

OF THE CORN EXPERIMENT, 1908.

TABLEJII.-RESULTS

L

20.7

....

....

C d

5s @ @

E$

.-C ui 22; M

sz

Fd ?g -?E :'.E2? .0


E;

g5

4 U

.....

.......... . . . . . .

.....\ ..... ..... ..... ..... ..... 11.20 ..... ..... ..... .....

.....

..... ..... ..... .....

..l..

..... ..... . . ,.. ..... .....

..... .... ..... 27.10 .....

..... .....

22.01

B

C

19 A

B C 20 A

B C

THE R E T U R N S I N THE C O R N C R O P S O F AND

18.11

.....

..... ..... ..... ..... .....

..... ..... 24.78 ..... ..... 17.86

..... ..... 15.31 .....

1898,1903,

1908.

The crop of 1908was in some respects abnormal, for it contained much larger quantities of dry matter and of nitrogen than were present in any of the following crops. This is readily explained by the fact that the stirring and aeration of the soil incident to sifting, mixing and weighing intensified oxidation processes to a very marked extent and made available comparatively large amounts of nitrogen and of other constituents of plant food. For the same reason the influence of the different nitrogenous materials applied in 1898 was not as consistently apparent as i t was in the succeeding years. For instance in 6B only 3.37 per cent. of the nitrogen applied was recovered in the crop; in 9h only 2.13per cent., in 9B only 6 . 5 7 per cent., etc. A comparison of Tables I, I1 and I11 will show, however, that the soils in each series yielded results which, in most cases, agree satisfactorily among themselves. By taking the averages for the several series we are permitted to see more clearly the influence of the different methods of treatment already outlined in the foregoing pages. The d a t a included in Table IV show the average yields of dry matter for the three seasons under consideration, They also show the yields of dry

T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y . July, 1909 matter in the unlimed soils 1A-20A and the limed soils IB-ZOCfor the season 1908. TABLE IV.-THE AVERAGEYIELDSOF DRYMATTER in 1898. 1903 AND Series. 1 2 3 4 5 6 7 8 9 10

11 12 13 14 15

16 17 18 19 20

1898, gms. 214.7 291.1 335.7 464.2 386.6 396.2 329.7 383.8 362.6 396.5 480.1 503.5 420.5 451.3 378.3 388.8 373 .O 322.6 429.9 382.8

1903, gms. 71 .O 160.3 208 .O 329.0 234.0 250.7 196.7 227.7 282 .O 387.0 359.7 433.7 283.7 408.0 303.7 376.3 286.3 225.3 398.3 347.3

1908. 1908. gms. 94.7 165.0 245 . O 346.3 258.0 263.7 221.7 306.7 327.0 379.7 468.7 493.3 312.0 415.3 305.0 410.0 272 .O 218.3 343.7 298.0

1908,A’s, gms. 65.0 150.0 224.0 340.0 236.8 254.0 188 .O 257 .O 288.0 383 .O 418.0 459 . O 296.0 379.0 296.0 386.0 239.0 182 .O 317 .O 248.0

1908,B’s and C’s. gms. 109.5 172.5 255.5 349.5 269.0 268.5 238.5 331.5 346.5 378.0 494.0 510.5 329.0 433.5 309.5 422 . O 288.5 236.5 357.0 323 .O

Taking the average yields of 1898 and 1903, as well as those on the unlimed soils in 1908, as given in the fourth column of Table IV, we note the very marked decline in the yields of Series I. I n 1898, the weight of the dry matter was 214.7 grams; in 1908 i t was only 65.0 grams. The decrease in the other series, from 1898 to 1903,was very marked. From 1903 to 1908 there was a decrease in some series and an increase in others, the differences being comparatively small in most instances. We may note, however, that the decrease occurred in Series I, 2, 7, IO, 14,15, 17, 18, 19 and 20; and the increase in Series 3, 4, 5 , 6, 8, 9, I I, 12, 13 and 16. The decrease in Series I and 2 may be readily explained by the failing supply of phosphoric acid and of nitrogen, respectively. The decrease in Series 17, 18, 19 and 20 may be explained by the accumulation of acidity in the corresponding soils, and the decrease in Series 7 by the diminishing supply of available nitrogen in the soil. On the other hand, the increase occurred in the series that have been receiving applications of manure, or of manure and nitrate together. At the same time, it should not be assumed that the ability of the different soils to supply available nitrogen to the crops had increased from 1903 to 1908. As will be shown later, the crops of 1908 contained a smaller proportion of nitrogen, and the yields of total nitrogen in that year were therefore smaller than those of 1903. As to the influence of the several methods of nitrogen treatment, we may conveniently compare the influence of the fresh manures when used alone

or in combination with nitrate with the influence of the leached manures when similarly used. We may likewise compare the action of the small and large applications of nitrate when used alone or in combination with manure, and the influence of nitrate, ammonium sulphate and dried blood when used alone or in combination with manure, In making these comparisons we note, in the first place, that all of the applications of nitrogen in Series 3-20 resulted in an increased crop yield as compared with Series z where minerals alone were employed, I n Series 4 where solid and liquid, fresh, was used the yield of dry matter was invariably larger than those in Series 3 where solid, fresh, was used. The superiority of the solid and liquid portion is also apparent in the combinations with nitrate, for we find the yields in Series 1 1 larger than those in Series 9, and the yields in Series 1 2 larger than those in Series IO. . The corresponding differences in the leached manures are not so marked. To be sure, when used alone, the solid and liquid leached gave somewhat higher returns than the solid, leached. But when these manures were used in combination with nitrate the corresponding relations were frequently reversed, as may be seen by comparing Series 13 and 15 and Series 14and 16. Comparing the returns from the fresh and leached manures, we observe that the solid, fresh, on the one hand, and the two leached manures, on the other, were not markedly different in their influence on the crop-yields. On the other hand, the solid and liquid, fresh, when used alone or in combination with nitrate proved to be decidedly superior to either of the leached manures. This should have been expected from the fact that the solid and liquid, fresh, contained a large proportion of amino compounds, readily nitrifiable, and, therefore, readily available to the growing plants. The relative influence of the small and large applications of nitrate is consistently maintained in Series 7 and 8 where i t was used alone and in Series 9-16 where i t was used in combination with the different manures. Comparing Series 9, 11, 13 and 15 with the corresponding even Series IO, 12, 14 and 16, we note that the larger application of nitrate almost invariably surpassed the corresponding smaller application. We may take it for granted, therefore, that nitrogen was really the controlling factor of growth in the cylinder soils, and that the amounts applied were not too large to be properly utilized by the crops.

VOORHEES A N D L I P M A N ON NITROGEA- I N F E R T I L I Z E R M A T E R I A L S . Comparing the relative influence of sodium nitrate, ammonium sulphate and dried blood (Series 8, 17 and IS)when used in equivalent amounts we note that the nitrate was (with one exception) superior to the ammonium sulphate and the latter superior to the dried blood. Similarly, when these materials were used in combination with the solid, leached (Series 14, rg and 2 0 ) ) the nitrate was always superior to the ammonium sulphate and the latter always superior to the dried blood. A more accurate comparison of the returns from these substances will be afforded in the table showing the nitrogen yields, but in this place i t may be noted that in so far as the corn crops are concerned the difference between the dried blood and ammonium sulphate is greater than that between the amnionium sulphate and sodium nitrate, no matter whether these materials were used alone or in combination with manure. It now remains to note the influence of the lime applied in the spring of 1908 on the production of dry matter in the several soils. That the linie favored the growth of the crop is evident from the larger yields in the limed soils as shown in the last column of Table IV. I n Series I the linie increased the yield of dry matter from 65.0 grams to 109.5 grams. I t happens, however, that in this series the supply of available phosphorus is even smaller than that of available nitrogen, and we behold therefore the interesting action of lime in making available a larger supply of phosphorus. I n the remaining series, nitrogen is the controlling factor, and the application of lime was indirectly equivalent to a n application of nitrogenous materials. The lime corrected in most instances the existing acidity and encouraged bacterial growth and the decomposition of the organic matter. We may note, particularly, the influence of the lime in Series 7, 8 and 18 where nitrate and dried blood were used. No manure has been employed in these series; their crop residues have been smaller and the bacterial activities less satisfactory than in other series where both crop and nianure residues were of considerable significance. For this reason, the addition of lime stimulated decay processes to a relatively greater extent in Series 7, 8 and IS. In Series 17 the acid conditions were even more pronounced than those in Series 18. There is reason to believe, however, that the lime added was not adequate to fully correct this acidity, hence the increased yield in Series 17 was relatively much smaller than that in Series 18. Furthermore,

403

the dried blood left larger residues in the soil than were left by the amnionium sulphate, hence the lime unlocked a larger reserve in Series 18. TABLEV.-THE AVERAGEPROPORTION O F NITROGEN IN 1898, Series. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

17 18 19 20

MATTER. 1903, 1908,

1908,A’s,

%.

7%.

%.

%

0.810 0.642 0.729 0.659 0.667 0.641 0.737 0.646 0.665 0.704 0.706 0.792 0.673 0.705 0.690 0.836 0.697 0.732 0,726 0.677

1.172 0.619 0.650 0.552 0.651 0.636 0.632 0.673 0.675 0.583 0.575 0.575 0.564 0.501 0.596 0.604 0.511 0.582 0.512 0.545

0.729 0.538 0.545 0.459 0.526 0.511 0.489 0.478 0.516 0.472 0.499 0.485 0.508 0.455 0.520 0.481 0.492 0.585 0.550 0.584

0.857 0.547 0.558 0.441 0.528 0.482 0.496 0.506 0.533 0.455 0.499 0.452 0.506 0.460 0.521 0.477 0.542 0.597 0.565 0.563

THE

DRY

1908,B’s and C’S.

%

0.692 0.534 0.539 0.467 0.522 0.544 0.488 0.467 0.509 0.481 0.499 0.499 0.511 0.453 0.520 0.483 0.472 0.580 0.544 0.592

The data concerning - the relative amounts of nitrogen in the corn crops of the different seasons and from the different series bring to light facts of considerable significance. I t is shown in Table V that the proportion of nitrogen in the crops of Series I was much higher than that in the crops of any other series. I n 1908, the dry matter of Series I contained 0.810 per cent. of nitrogen, and that of Series 6, 1.641 per cent. of nitrogen. In 1903, the dry matter of Series I was, relatively, even richer in nitrogen than i t was in 1908. I t contained 1.172 per cent. of nitrogen, or more than twice that present in the crops of some of the other series. I n 1908,the proportionate amount of nitrogen in the dry matter of Series I was smaller than i t was in 1903, but none the less much higher than that in the dry matter of the other series. This abnormally high proportion of nitrogen may be readily attributed to the retarded growth of the plants occasioned by lack of available phosphoric acid. There was not enough of the latter for the production of a greater quantity of plant substance and the available nitrogen compounds taken up could not be utilized to better advantage. Under actual field conditions similar results are undoubtedly produced by lack of available phosphoric acid or of available potash. The nitrogen is not utilized economically in so far as the plant substance is made to carry a proportion much above the average. But apart from the soils of Series I where phosphorus rather than nitrogen has been the controlling

404


element, we note appreciable differences in the proportionate content of nitrogen in the dry matter. We may observe, for instance, that in Series 3 the dry matter had a relatively higher proportion of nitrogen than in Series 4, notwithstanding the fact that the yield of dry matter and, as we shall see later, also of total nitrogen was higher in Series 4. Otherwise stated a larger quantity of available nitrogen compounds in the soil need not necessarily increase the proportion of nitrogen in the crop. I t is only when the store of available nitrogen compounds becomes very large that the plants take up more than they can utilize advantageously, and yield, in consequence, dry matter with an abnormally high proportion of nitrogen. On the other hand, applications of nitrogen judiciously made may increase the yields of dry matter not only directly, but also indirectly by encouraging a more economical utilization of the nitrogen derived from the soil itself. A very striking corroboration of the fact that the character of the season, as well as soil conditions, may affect the proportion of nitrogen in the dry matter is furnished by the corn crops of the three seasons under consideration. We may see a t a glance that the crop of 1898 was proportionally richer in nitrogen than the crop of 1903, and that the latter, in its turn, was richer than the crop of 1908. The only exceptions to be made here are those relating to the yields of Series I , 17, 18, 19 and 20. In the case of Series I, the utilization of the soil nitrogen was effected by lack of available phosphoric acid and in Series 17-20 by the gradually increasing acidity which was more pronounced here than it was in the remaining series. In the latter, however, the influence of the season, that is of the differences in precipitation, average temperatures, and sunlight directly affected the economy of utilization of the available nitrogen compounds, and led thus to variations in the ratio of nitrogenous to non-nitrogenous substances in the crop. The influence of the lime applied in 1908 is made manifest in the crops of that season. By comparing the proportions of nitrogen in the crops of the unlimed soils IA-~oAwith those in the crops of the limed soils IB-ZOC we observe a t once that the lime lowered in most instances the proportion of nitrogen in the dry matter. Now, as we shall see presently, the lime increased the yields of total nitrogen and acted, therefore, like a nitrogenous manure. We have seen, however, that, when applied within certain limits, nitrogenous manures

tend to lower the proportion of nitrogen in the dry matter ; hence the analogous action of lime may be readily explained. The figures in the fourth and fifth columns of Table V show us, in the first place, that the soils of Series 9, 11, 13 and 15 whether limed or unlimed produced dry matter richer in’ nitrogen than that produced in Series IO, 12, 14 and 16. Since, however, the series last mentioned were supplied with double the amount of nitrate in addition to the manure employed, and yielded in consequence a greater amount of total nitrogen, it follows again that under certain conditions small applications of nitrate may favor, to a greater extent than large applications, the production of dry matter rich in nitrogen. It should be remembered a t the same time, that these relations will not be maintained when the quantities of available nitrogen compounds present are large. It happens, thus, that in a few of the series the applications of lime increased, rather than decreased, the proportion of nitrogen in the dry matter. We see this increase distinctly in Series 6, IO, 12, 16 and 20; that is, in series that had large manure or crop residues. We may note in this connection that in the corn crop of 1898, the amounts of available nitrogen compounds were so large that the ‘larger applications of nitrate in Series IO, 12, 14 and 16 resulted in the production of dry matter richer in nitrogen than that produced with the aid of the smaller applications in Series g, 1 1 , 13 and 15. TABLEVI.-THE AVERAGE YIELDSOF TOTALNITROGEN. 1898, 1903. 1908. 1908, A’s. 1908. B’s and Series. gms. gms. gms. gms. C’s. gms. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

1.740 1.870 2.450 3.060 2.580 2.540 2.430 2.480 2.410 2.790 3.390 3.990 2.830 3.180 2.610 3.250 2.600 2.360 3.120 2.590

0.832 0.991 1.352 1.817 1.534 1.595 1.244 1.533 1.905 2.256 2.069 2.492 1.601 2.045 1.811 2.271 1.464 1.312 2.041 1.892

0.691 0.887 1.335 1.589 1.358 1.347 1.084 1.466 1.687 1.793 2.340 2.391 1.586 1.892 1.588 1.973 1.339 1.276 1.891 1.740

0.557 0.820 1.249 1.499 1.246 1.234 0,932 1.300 1.535 1.742 2.085 2.074 1.497 1.743 1.542 1.841 1.295 1.086 1.791 1.397

0.758 0.921 1.378 1,634 1.414 1.408 1.160 1.549 1.762 1.818 2.467 2.549 1.676 1.966 1.610 2.039 1.360 1.371 1.941 1.912

Table V showed .that there was a proportionate decrease in the nitrogen content of the dry matter from 1898 to 1903 and from 1903 to 1908. Table

VOORHEES A N D L I P M A N O N NITROGEN I N F E R T I L I Z E R M A T E R I A L S . VI shows that the decrease was absolute. Comparing columns I , 2 and 4 of this table we find this decrease to have occurred in all but one instance. As was to be expected, the decrease was greatest between 1898 and 1903. It has been pointed out that the nitrogen yields of 1898 were abnormal because of the treatment of the soil incident to the installation of the experiment. Between 1903 and 1908 the decrease was not so great, yet quite appreciable. In Series I , the nitrogen yield of 1908 was less than a third of the yield of 1898. In Series 2 , as well as in some of the other series, it was less than half. I t seems, therefore, that notwithstanding the comparatively large applications of manure and fertilizer in a number of the series the ability of the soils to yield maximum amounts of nitrogen in the crops was not maintained. We should have espected this a t least from Series IO, 12, 14 and 16 which have been receiving annual applications of manure at the rate of about 16 tons per acre and of nitrate of soda a t the rate of 320 pounds per acre. For all that there has been a distinct falling off in the nitrogen yields even in these series. As to the influence of the nitrogen treatment we find that the solid and liquid, fresh, furnished more nitrogen to the crops than was furnished by the solid, fresh. This is readily apparent in the yields of Series 3 and 4. On the other hand, the leached manures showed scarcely any difference. Moreover, there was but a slight difference between the yields from the solid, fresh and those from either of the leached manures. We may properly conclude, therefore, that the superiority of the solid and liquid, fresh, should be ascribed to the watersoluble amino compounds and their derivatives in the liquid portion. Comparing the yields of nitrogen from nitrate, ammonium sulphate and dried blood, where these were used without manure we find the efficiency of these materials to have been in the order named, I n 1898 the returns from these materials were 2.480 grams, 2.600 grams, and 2.360 grams, respectively. The corresponding figures in 1903 were 1.533 grams, 1.464 grams, and 1.312 grams, respectively, and in 1908, r.300 grams, 1.295 grams, and 1.086 grams, respectively. I t will be noted, therefore, that yields from Series 17 in 1898 furnished the only exception to the rule. We find, similarly, that the yields from the double quantity of nitrate were invariably larger than those from the single quantity. This applies not

405

only to the series where the nitrate was used alone, but also to those where it was used in combination with the different manures. A comparison of the yields in Series 9 and IO, 11 and 12, 13 and 14, 15 and 16 will show this invariably to have been the case. The combinations of nitrate and manure show, likewise, that the solid and liquid, fresh (Series I I and 12), was in all cases superior to the solid manure, fresh. I t now remains to consider the influence of the lime applied in 1908. We may note, in the first place, that the limed soils furnished in all cases more nitrogen to the crop than was furnished by the unlimed soils, Even Series I , where phosphorus is now the controlling element of growth, produced a larger crop of corn where lime was applied. In this case, however, the lime evidently helped to make available a larger amount of phosphoric acid, as well as of nitrogen. In Series 2 , where only acid phosphate and muriate have been applied for eleven consecutive years, the more readily decomposable portion of the humus had been largely depleted, nevertheless, the lime hastened the decay of the inert residues and made possible a markedly larger yield of nitrogen in the crop. I n how far the lime affected the increased utilization of the manure and crop residues in the other series may be seen from the following table which shows the increase over the yields of nitrogen in Series 2 . TABLEVII.-INCREASED YIELDSOF NITROGENOVER A'S, B's and C's. Series. gms. gms. 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

0.362 0.612 0.359 0.337 0.045 0.413 0.648 0.555 1.198 1.187 0.592

0.856 0.655 0.954 0.408 0.199 0.904 0.510

0.491 0.747 0.527 0.521 0.273 0.662 0.575 0.931 1.550 1.662 0.789 1.079 0.723 1.152 0.473 0.484 1.054 1.025

THE CHECKPLOT.

Difference, gm. 0.129 0.135 0.168 0.184 0.228. 0,249 0.227 0.076 0.382 0.475 0.197 0.223 0.068 0.198 0.065 0.285 0.150 0.515

The increase which may be attributed to the lime appears to be greater in the leached manure series (5 and 6) than in the fresh manure series (3 and 4). On the other hand, in series that had received applications of both manure and nitrate, the superiority of the leached manures is not as

T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y . July, 1909

406

apparent. I n fact the greatest increase to be ascribed to the lime occurred in Series 11 and 1 2 . The increase due to lime was but slight in Series 17 and 19 and very considerable in Series 18 and 20. The difference in question may be ascribed partly to the greater proportion of nitrogen residues in the dried blood series; and partly, also, to the strongly acid condition of the soils in Series 17 and 19; hence, to the insufficient amount of lime applied. PROPORTION‘ OF T H E

THE

APPLIED

NITROGEN

RE-

C O V E R E D I N T H E CROPS.

The yields of nitrogen in Series 2 must be attributed entirely to the soil humus, since no applications of nitrogen have been made in this series. By assuming a similar yield from the soil humus of the other series, and by subtracting this yield from that actually secured we obtain the yield due to the nitrogenous material added. For instance in 1908, the average yield of nitrogen in Series 2 was 0.887 grani, and in Series 3, 1.335 grams. Subtracting the former quantity from the latter we obtain 0.448 gram of nitrogen as due to the 4 grams of solid, fresh, applied in Series 3. This increase divided by the amount applied gives us the proportion of the applied nitrogen recovered. The remaining calculations carried out in this manner furnish the necessary data for a table showing the recovery from the several nitrogenous materials employed in the present experiments. The relations in question are brought out in the following table : TABLE VIII.-THE

PROPORTION OF NITROGENRECOVERED.

1898.

1903,

1908,

1908, A’s,

Series.

yo.

%.

%.

%.

3 4

7.44 22.04 16.80 22.36 69.58 44.38 9.64 10.11 24.62 30.28 11.56 19.07 19.76 20.14 44.24 42.36 21.77 16.55

9.00 20.70 13.70 15.10 25 .OO 35 .oo 19.10 22.80 22.60 27.10 12.80 19.10 17.20 23.10 34.90 20.70 18.80 16.30

11.20 17.55 11.77 11.50 25.26 37.35 16.74 16.32 30.40 27.10 22.01 18.11 14.67 19.57 27.90 24.78 17.86 15.31

10.72 16.97 10.65 10.10 14.36 30.97 14.96 16.61 26.46 22.60 14.16 16.63 15.10 18.40 29.32 16.94 17.10 10.36

5. 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Av.

1908 B’s

C’S,

and

%.

11.42 17.82 12.32 12.17 30.64 40.51 17.59 16.16 32.34 29.33 25.92 18.83 14.41 20.14 27.10 28.66 18.15 17.79

-

-

-

-

-

25.15

20.72

20.30

17.36

21.74

As indicated by the figures in Table VI11 the proportion of nitrogen recovered in the corn crops was not large. Taking the average recovery for

all of the applications we find that 25.15 per cent. of the nitrogen applied was recovered in 1898, 20.72 per cent. in 1903, and 17.36 per cent. in 1908 (unlimed soils). The averages just given were secured by adding the figures in the corresponding column and dividing by 18. They are somewhat higher than the real averages which may be obtained by dividing the average increase by the average amount of nitrogen applied. It happens, thus, that of the various applications of nitrogen less than one-yuarter was returned in the crops. Not the least interesting fact in this connection is the much higher recovery in the oats crop that followed the corn crops of 1898 and 1903. I n spite of the shorter growing season these crops were apparently able to secure more nitrogen from the materials applied. The d a t a a t hand show us also that the recovery from the solid and liquid, fresh, was greater than that from the other manures, a fact which may be readily explained from the composition of the several manures. We may note, likewise, that the returns from the single application of nitrate (Series 7) were smaller than those from the double application in 1903 and 1908. I n fact the single application in 1908 showed a recovery of only 14.36 per cent. (unlimed soil) probably because of the increasing acidity of the soil. The double application of nitrate maintained its superiority over the single application even when i t was used in combination with manure. LVith but one exception Series IO, 12, 14 and 16 showed a higher recovery than the corresponding Series 9, I I , I 3 and I 5. The falling off in the recovery from the nitrogen applied was marked in Series 17 and 18. I n the first of these the proportion recovered was decreased from 44.24 per cent. in 1898 to 29.32 per cent. in 1908, while in Series 18 it was decreased from 42.36 per cent. to 16.94 per cent. Moreover, the decrease was considerable even in the series where the ammonium sulphate and dried blood were used in combination with manure. Thus in Series 19 the recovery decreased from 21.77 per cent. to 17.10 per cent., and in Series 2 0 from 16.55 per cent. to 10.36 per cent. The application of lime in 1908 enhanced the recovery in all b u t three of the series. Among the latter is included Series 17 where the application of lime was not sufficient to neutralize all of the acidity. Examining the increase due to lime somewhat more critically we note i t to have been particularly marked in Series 7, 8 and 18 whose

VOORHEES A N D L I P M A N ON NITROGEN I N FERTILIZER M A T E R I A L S .

16.26 per cent., and the actual recovery 9.64 per cent. In other words, out of a possible 16.26 per cent., 6.62 per cent, were not recovered. It might be concluded, therefore, from the results of 1898, that denitrification had taken place in the combination series; that is, a portion of the nitrate applied had been destroyed in the presence of the manure. But when we come to examine the results for 1903 and 1908 we find no such evidence of denitrification. I n these years the actual recoveries exceeded the calculated recoveries in nearly all of the combination series, while in the few exceptions the calculated recoveries exceeded the actual recoveries but slightly. The apparent denitrification in 1898 must be attributed, therefore, to the inability of the plants to utilize thoroughly the comparatively large amounts of available nitrogen compounds in the combination series. Moreover, if the differences noted in 1898 were really due to denitrification they should have been greater in 1903 and greater still in 1908 on account of the cumulative effect of the annual applications of cow manure. As a matter of fact there was no such increasing apparent effect of denitrification. It may be concluded, in view of the data just pre-

soils receive no applications of manure. Similarly, in some of the series receiving both nitrate and manure the increase was coniparatively large, namely, in Series I I , 1 2 and 13. To these may be added Series 2 0 receiving applications of solid, leached, and of dried blood. It should be pointed out here that the figures in Table VI11 were obtained b y subtracting the average yield of Series 2 from that of each nitrogentreated series, and dividing the difference b y the amount of nitrogen applied. The figures thus secured represent the average recoveries. Where the unlirned and limed soils were considered separately, the yield of 2A was subtracted from the corresponding yields of 3A-20AJ and the average yield of 2B and 2C from the corresponding yields of 3B-20C. T H E ACTUAL AND CALCULATED R E C O V E R I E S O F NI-

TROGEN.

It will be remembered that in some of the series, manure was used alone, that in other series nitrate, ammonium sulphate or dried blood was used alone, and that in other series still the two classes of nitrogenous substances were used in combination. Now, i t has been shown that by subtracting TABLEIX.-ACTUAL

AND CALCULATED

1898.

Series.

.

7 and 3 i n . . . 8and3in 7and4in.... 8 and 4 i n . . 7 and 5 i n . , 8 and 5 i n . . , 7 and 6 i n . . , 8 and 6 i n . . . . 17 and 5 i n . . . 18 and 5 i n . . .

....

.. .. . . . .

Series.

Actual, per cent.

9 10 11 12 13 14 15 16 19 20

9.64 10.11 24.62 30.28 11.36 19.07 19.76 20.14 19.75 15.85

3

7

Calculated, Not recovered, Actual, per cent. per cent. per cent. 16.26 16.61 28.16 27.14 25.46 24.55 30.96 29.34 24.67 22.41

RECOVERIES,

1903.

7

6.62 6.50 3.54

.....

14.10 5.48 11.20 9.20 4.92 6.56

the yield of Series 2 from that of any of the nitrogentreated series the increase due to that particular treatment is obtained. Knowing, therefore, the increase due to manure on the one hand, and to nitrate on the other, we may calculate the increase that should occur when the two are used in combination. We have determined thus the actual and calculated recoveries for the several series as shown in the above table. The differences between the calculated and actual recoveries, as shown in Table IX, appear greatest in 1898. In that year the calculated recoveries exceeded the actual recoveries in all of the combination series except in Series 1 2 . For instance, in Series g the calculated recovery was

407

19.1 22.8 22.6 27.1 12.8 19.1 17.2 23.1 18.8 16.3

-

1908.

.

7

Calculated, Kot recovered, Actual, Calculated, Not recovered, per cent. per cent. per cent. per cent. per cent. 11.6 16.3 21.4 24.7 15.5 19.7 16.7 20.6 19.8 15.7

... ... ... ... 2.7 0.6

... ... 1

.o

...

16.74 16.32 30.40 27.10 22.01 18.11 14.67 19.57 17.86 15.31

13.49 18.50 18.81 23.08 13.97 18.92 13.74 18.72 16.42 15.44

.... 2.18

.... .... ....

0.81

.... .... ....

0.13

sented, that under ordinary conditions of field practice denitrification is not a phenomenon of economic importance. I n market gardening and in greenhouse work the conditions are different, and the significance of denitrification may be greater. However, i t would be beyond the scope of the present paper to discuss those other conditions here. THEACTUALANDCALCULATEDRECOVERIESFROMTHE U N L I M E D AND L I M E D S O I L S I N

1908.

As supplementary to the data of Table IX, i t would be proper to consider here the corresponding relations in the unlimed and limed soils of 1908. These relations are shown in the following table:


408

TABLEX.-ACTUAL AND CALCULATED RECOVERIES, 1908. Unlimed. c Limed. Calcu- NotreActual, lated. covered, Actual, Calcu- Not reSeries. Series. %. 70. %. lated, %. covered, $.

-.

r0.

7&3in 8 & 3 in 7&4in S & 4 in 7&5in 8 & 5 in 7 & 6 in 8&6in 1 7 & 5 in 18 & 5 in

9101112131415161920-

14.96 16.61 26.46 22.60 14.16 16.63 15.10 18.40 17.10 10.36

11.32 16.38 16.55 20.88 11.25 16.32 10.79 15.93 16.03 12.42

.... .... ....

.... .... .... ....

.... ....

2.06

17.59 16.16 32.34 29.33 25.92 18.83 14.41 20.14 18.15 17.79

14.56 19.55 19.92 24.16 15.31 20.20 15.18 20.10 16.58 16.70

.... ....

soils. Information more definite in character than that already a t hand can only be secured by means of carefully performed soil analyses. THE

RELATIVE AVAILABILIT\'

O F THE NITROGENOUS

3.39

MATERIALS.

.... ....

By taking the returns from the mtrate nitrogen as IOO and by calculating the returns from the other materials on this basis we may secure a statement as to the relative availability of these materials. Properly tabulated figures representing relative availabilities may be quite helpful in the study of the comparative values of nitrogenous substances used as manures. The following table shows the relative availabilities of the several nitrogenous materials employed in the cylinder experiments for the corn crops of 1898, 1903 and I 908. The data of Table X I bring out in a somewhat more concrete form facts already considered in preceding pages. We note the comparatively high availability of the ammonium sulphate, and

1.37 0.77

....

.... ....

As is shown in the above table, the actual recovery exceeded the calculated recoveries in 9 out of IO cases in the unlimed soils, and in 7 out of I O cases in the limed soils. This furnishes us an apparent indication of denitrification in the limed soils, the more so since in Series 9 the actual recovery exceeds the calculated recovery by more than 3 per cent., while in Series I O the calculated recovery exceeds the actual recovery by nearly as much. Similarly, in the other odd series where 5 grams of nitrate were applied the differences

TABLEXI.-RELATIVE AVAILABILITIES. 1908,

1908.

Average for all ETORS,

1898.

1903.

1908.

A'S.

B's and C's.

1898-1 907,

Sodium nitrate.. ......................... 100 .OO Ammonium sulphate. ..................... 99.50 Dried blood.. ............................ 95.40 Solid manure, fresh.. ..................... 16.76 Solid and liquid, fresh. . . . . . . . . . . . . . . . . . . . 4 9 . 6 6 Solid manure, leached.. . . . . . . . . . . . . . . . . . . . 3 7 . 8 6 Solid and liquid, leached. . . . . . . . . . . . . . . . . . 5 0 . 3 8

100 .o 99.8 59.2 25.7 59.2 39.2 43.2

100.0 74.7 66.3 30.0 47 .O 31.5 30.8

100 .o 94.7 54.7 34.6 54.8 34.4 32.6

100.0 66.9 70.7 28.2 44 .O 30.4 30.0

100.0 69.7 64.4 35.9 53 . O 38.9 43.1

between the actual and calculated recoveries are much greater than they are in the corresponding even series where I O grams of nitrate were used with the manure. It appears, therefore, that larger losses occurred where larger amounts of nitrate were used and that these losses might have been due to denitrification. I t might be assumed, moreover, that the lime favored denitrification, since the corresponding differences are not so marked in the unlimed soils. However, the evidence a t hand is inadequate as a proof of denitrification. It is more likely that the apparent losses of nitrogen were caused by the transformation of available into inert compounds. Indeed the cornparatively low recoveries of the nitrogen applied for the corn crops seem to point strongly to the accuracy of this conjecture. Now, since lime encourages the rapid multiplication of soil bacteria, it is not a t all improbable that more nitrate was thus transformed in the limed than in the unlimed

of the solid and liquid, fresh, among the manures. We note, also, that in the limed soils the relative availability of the ammonium sulphate and of the several manures is diminished. Otherwise expressed, the sodium nitrate series were favored to a greater extent than the other series (Series 18 excepted) by the application of lime. I t appears, further, that ammonium sulphate is a relatively better source of nitrogen for corn than it is for other crops. This may be ascertained by examining the data in the last column of Table XI. The relative availabilities given there represent the average for the ten-year period 1898-1907. The ammonium sulphate is shown there to have a relative availability of 69.7 as against 99.5, 99.8 and 94.7 (unlimed soils) for the corn crops of 1898, I 903, and I 908, respectively. The differences appear even more pronounced when the relative availabilities for 1898 and 1903 are excluded from the general average for the ten-year period.

*

Experiments on the Utilization of Nitrogen in Fertilizer Materials

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