The effect of cultivation on the availability of soil nitrogen in some Manitoba soils

Abstract

Samples were taken from virgin and cultivated sites in each of three soil associations in the Black earth zone to study the effect of cultivation on available soil nitrogen. The investigations have shown that cultivation affected the organic matter, nitrogen content and nitrogen distribution in one of the soils to such and extent that rate of nitrification was reduced considerably. In the other two soils cultivation caused a smaller loss in organic matter and nitrogen content and even appeared to increase nitrification of the remaining nitrogen fraction. Field trials were conducted with ammonium sulphate and ammonium nitrate fertilizers on barley, wheat and oats. In some cases the ammonium sulphate and ammonium nitrate was supplemented with ammonium phosphate fertilizer. Significant yield increases were obtained with ammonium sulphate fertilizer. When applied in the fall, ammonium sulphate was more effective that ammonium nitrate as a nitrogen carrier.