Effect of Straw on Availability of Nitrogen to Cereal Crops

Abstract

In studies conducted from 1955 to 1961 on several soils in Manitoba, incorporation of straw into the soil did not generally induce a nitrogen deficiency in the succeeding cereal crop. When soil samples with straw were incubated in the laboratory, and when straw was applied in fallow fields, nitrate release was reduced markedly. Presumably low temperatures and lack of moisture in the fall and spring reduced the rate of straw decomposition. In this case, the level of available nitrogen would not be reduced appreciably by saprophytic microorganisms. In the area cereal crops are seeded before soil temperatures are high enough for rapid straw decomposition in the spring and the crop competes successfully with the microorganisms for nitrogen.