Arrril. 1922
THE JOURNAL OF INDUSTRIAL A N D E’NGINEERING CHEMISTRY
299
Cu1ti vat i on an d Nitrogen Ferti li zat i on By H.A. Noyes, J. H.Martsolf and H. T. King ATELLON INSTITUTE O F INDUSTRIAL RESEARCH, PITTSBURGH, PENNSYLVANIA
I€ is the practice of some grape growers to make two applications ofniirogen to their vineyards, thefirst at plowing time, and the second near the blossoming period. The present investigation deals with the value of this second application, as indicated by the determination of nitrates in the soil under differing vineyard conditions. The results tend to show that organic matter favors nitrate formation in soils, as does also cultidation. Early application of nitrate of soda and proper cultivation give considerable quantities of nitrates in vineyards at the time second applications are often made. Turning under cover crops in vineyards in the spring gives increased soil nitrate content. The amounts of nitrates found in well-cultivated vineyards at regular intervals during the growing season show nitrates to be present in quantity except at the start of the growing season. A n application of available nitrogen at plowing time appears suficienf for properly cultivated vineyards. GRICULTURAL practice and scientific investigation have shown that available nitrogen is necessary for the proper growth of plants. The sources of nitrogen are soil organic matter, the air, from which nitrogen is combined and made available by bacterial activities and fertilizer mat#erials. Publications from several of our Experiment Stations and other scientific articles give data showing that cropped soils are lower in organic matter than virgin soils. This lowering of organic matter is evidence that bacterial activities have played a large part in plant nutrition. The work of Noyes and Canner*,* shows a marked correlation between aerobic bacteria and the nitrification of five types of soil, variously treated with lime and fertilizer, when they were kept under conditions which eliminated some of the variables encountered in field work. Since a large proportion of the soil nitrogen is made available through bacterial activities and bacteria have been shown to be agents for the fixation of atmospheric nitrogen, it is very important that agriculturists put into practice systems of soil management which will be favorable to the multiplication of desirable soil bacteria. Recent soil investigations tend to show that beneficial soil bacteria require oxygen, a source of carbohydrate material for their energy, and a low acid reaction of the media in which they are growing. Stated in terms of agricultural practice, this means that cultivation, organic matter, and a soil less than moderately acid are essential for desirable bacterial activities. Sitrogen fertilization experiments can be divided into two classes on the basis of whether the plants under tests are annuals or perennials. The perennial plants, illustrated by our common fruit trees, have stored in them each fall a certain amount of reserve material in preparation for their growth the coming spring. This reserve material has not been shown to contain any large amount of available nitrogen. The atmospheric conditions of our temperate climate are usually favorable for the growth of the tree long before the soil has warmed up enough for-active bacterial activities. Results where nitrate of soda has given beneficial effects on apple trees can be readily found by those desiring them. This is taken by the authors of this paper
A
1 Presented before the Division of Fertilizer Chemistry a t the 62nd Meeting of the American Chemical Society, New York, N. Y., September 6 to 10, 1921. * Numbers in text refer to Bibliography a t end of paper.
to show that the responses of perennial plants to available nitrogen early in the season are largely due t o lack of sufficient bacterial activity in the cool soil at that time. The fertilizer industry furnishes nitrogen in two forms, namely, that which is termed available and that which is termed unavailable. Out of this comes a more or less common belief that we buy some readily available nitrogen for immediate use and other nitrogen to become available a,nd ready for use at a later date. It is well known that vegetable gardening experiments often call for applications of available nitrogen at different intervals. We find the practice of some growers in the Chautauqua and Erie Grape Belt is to make two applications of nitrogen to their vineyards. The first application is made at plowing time and the second application occurs later near the blossoining period. The object of t8hework reported in this paper was to find out to what extent this second application of nitrogen fertilizer may be expected to give returns, as judged by the amount of nitrates found present in the soil under different vineyard conditions, and to see if these results correlat8ewit,h other data. EFFECT OF AMPLEAERATION Experimental work carried on under conditions of ample aeration (because of the open nature of the soil used) is reported in Table I. The crop used was head lettuce. Samples of soil were taken every 2 wks. from November 9 to April 16. The results in crop yields, nitratest in soil, and nitrates a,fter incubation are given in the table. TABLP, I-CROP,
NITRATES, AND NITRIFICATION O N LIGHT SANDYSOIL IN GREENHOUSE EXPERIMENTS Nos, P . p. nl. on Dry Sol1 Weight after of As IncubaApplications, Rates per Acre Crop Sampled tionl Check . . . . . . . . . . . . . . . . . . 1~5.9~ 374.21 8.5 386,l
45.1
436.7
66.0
482.6
36.6 29 5 66.8
569.3 371.1 577,6
5-!on dry manure with complete fertilmer.. ............................ 1503 54.5 717.2 Leaf mold giving equal ’ to 5-tOn dry manure. 30.2 527.2 10-ton dry manure. , , , , , . , , . 64.5 134.1 Leaf mold giving equal orga ter to 10-ton dry manure.. 66.2 778.1 1 6 wks.’ incubation a t 20’ C. and constant moisture content with 5 cc. .of 2 per cent ammonium sulfate solution. 2 Figures are average for ten dates of sampling a t 2-wk. intervals.
The results are significant. There is no caSe where organic matter was added in which the nitrates after incubation with ammonium sulfate were lower than a treatment where organic matter was not added to the soil. The data show that we tend to have the largest crop where organic matter is added to the soil. The nitrates in the soil for the period under investigation were doubtless affected by the growing crop; however, four out of the five highest average nitrate t Soil samples taken with a bacteriologists’ soil sampler described in the J . A m . SOC.Agron., 7 (1915), 239. All samples were taken to the laboratory and the analysis started immediately according to the method described in THISJOURNAL, 11 (1919), 213. The determinations were made o n the moist (field) sample in every case. Moisture was determined by drying 10 g. of soil to constant weight a t 100’ C. Nitrate results were calculated to moisture-free soil.
300
THE JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMIXTRY TABLE 11-NITRATE
Vol. 14, No. 4
YOUNG ORCH.4RD HAVINGDIFFERENTSYSTEMS OF SOIL MANAGEMENT' (Nitrates as Nos per Million) 7 Clean Culture Cover Crop -Accumulative Straw Mulch--Sod Several Years--Moisture Before After Moisture Before After Moisture Before DATE Per cent Inc. 1nc.l Per cent Inc. Inc.2 Per cent Inc. 5/19/14 10.2 119 201 10.6 48 262 5.0 22 9/16/14 14.0 209 17.3 102 168 242 15.4 47 11/ 9/14 18.5 194 11 23.5 362 28 19.4 4 26.6 6/14/15 55 318 29.8 25 234 26.5 6 15.0 71 1/15 249 101 19.8 7 426 16.5 6 7/27/15 15.0 88 17.2 268 60 274 15.8 9 8/19/15 69 20.5 18.9 238 9 289 21.5 9 1/24/16 26 22.6 23.0 321 33 411 24.6 23 5/ 2/16 21.0 22.8 0 2355 66 5017 22.7 14 7/18/16 14.6 936 80 14.6 41 885 8.8 1 11/23/16 15.9 14.9 159 0 1 167 17.5 0 AVERAGE 17.5 59 495 19.5 44 779 17.6 13 1 Soil was silty clay loam averaging 0.15 per cent nitrogen. 2 6-wk. incubation a t 20° C. and constant moisture content with 5 cc. of 2 per cent solution of ammonium sulfate. STUDIES I N
-
After Inc.9 170 237 235 303 290 262 268 359 4845 771 167 719
To check up this point the writers are presenting some data (Table 111) secured in sodded land one month after ammonium sulfate and nitrate of soda were added in comparative tests. The soil was a silty clay and had been in sod for a t least 3 yrs. It was well packed and firm; therefore the data should show the extent to which ammonium COMPARISON O F SYSTEblS OF SOIL MANAGEMENT sulfate has given nitrates in excess of plant requirements Considerable work has been reported by C. B. L i ~ m a n , ~under the conditions of the experiment. The check shows Albrecht,' Gainey and Metzler,3 Jensen,4 Richard~on,~only a small amount of nitrates and the soil is one which Lyon and Biz~e11,~ Whiting and Schoonover,** and others is relatively high (for the locality) in volatile matter and nion the supposed effects of different crops, associated crops, trogen. and systems of soil management on nitrate formation in the TABLE 111-NITRATES IN SODDED LANDONE MONTHAFTER APPLICATIONS OF NITRATEOF SODA AND AMMONIUM SULFATE soil. The work of these investigators has been conducted (Samples taken June 29, 1920) under a wide range of conditions; first one factor and then NOa, P. p. m. of Increase Due t o Applications per Acre Lhs. Dry Soil NaNOs (NHdk301 another has shown itself as being of great importance when Nothing. . . . . . . . . . . . . . . . . 9.5 ... ... the results were summarized. 80 little work has been conNitrate of soda. , . . . . . . 310 73.0 63.5 ... Ammonium sulfate. . . . . 310 l5,O 5.5 ducted where the systems of soil management known as Nitrateofsoda.. .. . . . . . 620 326.0 316:5 ... mulch, sod, and cultivation have been compared, side by Ammonium sulfate. . , . , 620 23.0 13.5 Nitrate of soda. . . . . . . , . 930 882.0 SiZ: 5 ... side, that the present writers have included data from an Ammonium sulfate . . . . . 930 17.0 ... 7.5 experimental orchard13 where these systems have been practiced for several years. The differences in organic matter The results indicate that: content between the various treatments were not considered 1-Nitrates in the soil increase with increased applications of sodium a controlling factor, as shown by analyses given elsewhere nitrate. in the b~1letin.l~ 2-Ammonium sulfate, though applied in quantities equal to the nitrate The figures reported appear in acco'rd with the results of soda and carrying more nitrogen, does not nitrify readily in this compact obtained by Gainey and Metzler3 when they compacted sodded soil. soil, though high in organic matter (for the locality) and of modersoil beyond a certain point and prevented active nitrifioation. ate3-The acidity, does not contain a large quantity of nitrates under field condiThe big difference between their results and those reported tions, in the table above is that the low nitrate content regularly Samples were taken from six vineyards in 1920 at the time occurs on the sod plot where a natural packing of the soil has taken place. The amounts of moisture do not prevent the second application of nitrogen fertilizer is usually made nitrification when the soil is subjected to nitrification tests (Table IV) to find out what quantities of nitrates were by the so-called beaker method, On the basis of these present in the soil from natural sources and from applications data, aeration might be assumed to account for both these of nitrate of soda made earlier (at plowing time). results and those obtained by Gainey and Meteler. IN VINEYARD SOILSAT TIMESECOND APPLICATION OF Albrecht' says, "Plowing has a very significant effect TABLEIV-NITRATES NITRATEO F S O D A I S USUALLY MADE toward increasing nitrates." Noyes and Canner* show that Nitrate of Nos Soda P.p. m.'of five soils which give a direct relationship between aerobic SOIL Status of Organic Cultivation Lbs. per Matter in Soil Practiced Acre ?% counts and nitrates when variously limed and fertilized No. Kind of Soil Medium low Thorough None 352 1 Silty clay failed to show the presence of nitrates after being held satuThorough 767 678 rated with water for about 10 mo. Excess moisture reMedium low Poor None 18 2 Silt loam Poor 643 121 sulting from saturation or lack qf air due to the presence of None 73 3 Sandyloam Average for soil type Thorough excess moisture caused no nitrates to be found in the fully Thorough 570 105 Average for soil type Thorough None 52 4 Silt loam saturated soils either before or after incubation by the Thorough 600 55 beaker method and this would indicate that aeration has None 38 5 Gravelloam Average for soil type Thorough Thorough 242 33 a definite relationship to nitrification. High for locality Fair None 92 6 Silt loam Lohnisc found that, in respect to nitrification, aeration Fair 564 66 is of great importance. Schloesing'o in his experiments also showed that the amount of nitrate nitrogen found was On the heavy soils, 1 and 2, cont,aining medium to low in direct proportion to the amount of oxygen supplied. quantities of organic matter nitrates were present, but not in as great quantities as where large applications of nitrate ADDITIONOF NITRATES of soda had been made at plowing time. On the soils of medium organic matter content, 3, 4,and 5, . Gainey2 gives results showing that when conditions are such that nitrification is hindered, ammonification increases. we have again comparisons between nitrification without contents occur on plots receiving organic matter. This table shows, therefore, that (1) nitrates tend to increase in proportion to the active organic matter present in the soil,"((2) a growing crop has an effect on the nitrates present in the soil.
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April, 1922
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 CHEMI8TRY
nitrate fertilization at plowing time and with rather heavy applications of nitrate of soda a t plowing. The cultivation was well carried out and there was no great difference between the plots without and with the nitrate of soda application. Soil G is comparatively virgin soil, high in organic matter, and the heavy application of 564 lbs. of nitrate of soda per acre did not give as high nitrate content to the soil on the date the samples were taken as the check. The data show no discernible lack of nitrates present where the cultivation had been well carried out.
PLOWING IN COVERCROPS The result of plowing under cover crops on the amount of nitrates Iound in the soil on different dates is given in Table V TABLE V-COMPARISON OB NITRATESIN WELL-CULTIVATED VINEYARD ON GOODGRAVEL L O A M THROUGH SEASON1 M a y June June July July Aug. Aug. Sept. Av. 24 10 23 7 21 5 19 1 Check 392 54 119 68 51 39 29 16 52 Covercrops.. 66 99 104 85 85 50 __a9 158. -68-Difference due t o covercrop 27 45 -15 17 34 11 10 1 16 1 400 lbs. high-grade complete fertilizer used a t plowing time. 2 Figures are nitrates per million pounds of dry soll. 8 Cover crops actively growing.
,........... ..... .......
which gives the comparison of nitrates between cover crop plots and the check plot in a well-cultivated vineyard on good soil for the season of 1921. This vineyard was fertilized rather liberally early in the spring, and any increase in nitrates on the cover crop plots can therefore be directly attributed to the effects of increased bacterial activity due to readily decomposable material furnished by the cover crops. Except on June 23 the cover crop plots gave a higher nitrate content than the check. The cover crops were planted again in August, and September 1 finds that the young cover crops have apparently reduced the nitfate content to practically the same as the check plot. Without any second application of fertilizer we find in iboth sets of figures plenty of nitrates present during the active growing season and u p to the time the cover crops are planted. An average of 52 parts of nitrates on the check plot is equivalent to 213 lbs. of nitrate of soda per acre. The average of 68 for the cover crop plots is equivalent t o 251 lbs. of nitrate of soda per acre. I n summarizing this table we are led to believe that active organic matter, which serves as food for soil bacteria, increases nitrate production. These results bear out the results of Whiting and Richmond,*l who find that plowing under sweet clover before corn “furnishes large amounts of nitrate nitrogen for the corn crop.” Calling attention to the very general agricultural practice of having corn follow the green manure crop in the rotation and the generally accepted beneficial effects of turning under a green manure crop, the data so far given.in this article are confirmatory of the expressed belief that aerobic bacterial activities in the presence of a source of carbohydrate material give available plant fobd in quantities that produce increased crops. COMPARISON OF ADJACENT VINEYARDS
To see what effect different systems of management have on vineyards on the same soil and adjacent to one another, the data in Table VI were procured. On all except one date of sampling the highly cultivated vineyard had the greater amount of nitrates present in the soil. The quantities of nitrate in the highly cultivated vineyard were always ample, for the average of 53 p. p. m. 3s equivalent to 218 lbs. of nitrate of soda per acre. The
301
TABLEVI-COMPARISON OF NITRATES IN ADJOININGVINEYARDS THROUGH SEASON M a y June June July July Aug. Aug. Sept. Av. 24 10 23 7 21 5 19 1 High cultivation.. 621 60 60 58 81 46 40 212 53 Average cultivation forgrapebelt.. . 25 39 69 29 43 11 148 17 31 Difference for high cultivation . . . . . 37 21 -9 29 38 35 26 4 22 1 Figures are nitrates per million pounds of dry soil. 2 Cover crop of weeds. 3 Plowed recently, turning under summer’s growth of weeds.
. . .
figures for August 19 and September 1 are taken to show that the plowing done in the average cultivated vineyard about August 1 tended to increase nitrification, while a heavy natural growth of weeds serving as a cover crop decreased the nitrates present in the highly cultivated vineyard. I n summarizing this table it appears that cultivation increased nitrate production. Lyon and Bizsell? give data showing the effects of one crop on another as expressed in the nitrate content of the soil. Is it not signscant that these beneficial effects so regularly accompany associations of crops that would not tend to impede soil- aeration? NITRATESAND MOISTURECONTENT Nitrates and moisture results obtained bi-weekly in 1921 are given in Table VII. TABLEVIITNITRATES
MOISTUREI N VINEYARDS FOR SEASON OF 1921 Sodium Nitrate per Acre to Which No3 Content Is Equivalent for Moisture NOa, P. p m. Average Depth Sampled in Soil of Dry Soil Lbs. Per cent AID
May 6 (Plowing time).. . May 2 4 . . . Tune 10 ... . . June 2 3 . . , , . . . . . July 7 . . . July 2 1 . . , , , August 5 (Cover crop sowing). . . August 19.. . , . September 1 (Cover crop growing).
238 452 464 288 304
58
13.2 18.3 12.5 13.7 13.1 16 3
79 60
325 247
14.7 17.3
... . .... . . . . .57
234
12.l
. . .. .. .. .. .. . . . . . . . .. . . . .. .. .. .. ..
. . . .-.. . ..
This table gives the results of studies carried on with twenty-four plots located on at least three distinct types of soil scattered over an area of 10 sq. mi. There was R difference of over 500 ft. in elevation between the lowest and highest plot. The nitrate and moisture contents of the soil are given at 2-wk. intervals. The nitrates start with 14 p. p. m., the equivalent of 58 lbs. of nitrate of soda per acre, and increase until June 23 when the maximum, equivalent to 464 lbs. of nitrate of soda per acre, is reached. The data show that moisture did not bear a definite relation to the nitrate content of the soil. These data from twenty-four plots receiving different treatments as to fertilizer but proper cultivation indicate that applications sf nitrate of soda later than M a y 24, 1921, would have been wasted. DURATIONO F
EFFECT O F INITI.4L
NITRATE ADDITION
The literature cited and the results given in the foregoiqg do not give information as to how far into the season the effects of the initial application of available nitrogen extend. Our measure of this has been a comparison on different dates of the nitrate content of plots where nitrate has been applied and the check plots beside them. The data for 1921 are given in Table VIII. In all cases the nitrate of soda plots show greater nitrate content than the checks. When we consider that 100 parts of nitrate are equivalent to more nitrate of soda than
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