The influence of wheat straw on the accumulation of nitrates in the soil
1921
Scott, H.
Applications of straw to soil in the greenhouse caused a marked decreased in the nitrate content. The loss was proportional to the amount of straw added. As decomposition of the straw progressed the nitrates in the soil increased but remained lower in the presence of straw than in the untreated soil. The addition of nitrogen as (NH4)2SO4 with the straw caused a more rapid accumulation of nitrates. Heavy fall applications of straw to wheat growing in the field retarded growth the following spring, delayed the ripening of the grain, and reduced the yield except on soils having a high nitrate content when the straw was applied. Four tons of straws per acre worked into the surface 6 inches of uncropped soil resulted in a lower nitrate content the following spring, but during the summer the accumulation of nitrates was equal to that in the untreated plats. Two tons of straw per acre worked into the surface 6 inches did not lower the nitrate content of the soil the following spring. Four tons of straw applied as a top dressing reduced the nitrate content the following spring and summer. This treatment showed, thruout the summer, the highest moisture content, the lowest temperature, and the lowest nitrate content of any of the treatments. Two tons of straw applied to the surface did not show an appreciable decrease in nitrates the following spring and the accumulation of nitrates was fairly great by the end of summer.
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