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Relative lime needs of sulfate of ammonia and nitrate of soda and of different crops

Hartwell, B.L., Damon, S.C.
Agronomy journal 1927 v.19 no.9 pp. 843-849
ammonium sulfate, phosphoric acid, liming, potassium fertilizers, crop yield, nitrates
This paper contains the results for 1915 to 1926 of a field comparison, conducted since 1893, of equal amounts of nitrogen in sulfate of ammonia and nitrate of soda accompanied by liberal amounts of phosphorus and potassium. Prior to 1915, each source of nitrogen had been accompanied by an equal amount of lime, and also had been used without lime. Subsequently, extra lime was applied to the more-limed sulfate plat to make its reaction like that of the limed nitrate plat. The average pounds of calcium oxid per year during the 34 years was 275 applied to the limed nitrate plat and 422 to the more-limed sulfate plat. The average annual application of nitrogen was 49 pounds, therefore, each pound of nitrogen required 3 pounds more of calcium oxid to attain an equal soil reaction; that is, 100 pounds of sulfate of ammonia required about 80 pounds of hydrated lime, or 120 pounds of limestone, more than was required by 128 pounds of nitrate of soda supplying the same amount of nitrogen. When completely oxidized, sulfate of ammonia supplying 1 pound of nitrogen would require for neutralization 4 pounds of calcium oxid. It is believed that this should be the basis of future liming to maintain the sulfate plat at the same reaction as the nitrate plat. The relative lime-response of the 22 different kinds of crops is expressed as low, medium, or high. Because the two extremely sensitive crops to acid-soil conditions, spinach and lettuce, tended to yield less with sulfate than with nitrate, determinations are included of the soil content of active alumina and of nitrate-nitrogen under the two conditions. In general, the crop yields were about alike with the two sources of nitrogen when the same reaction of the Merrimac silt loam was maintained.