作者在灰色森林土上做田间试验,并似盆栽试验作配合。供试作物有春小麦、燕麦、大麦、荞麦、马铃署、玉米。利用~(15)N标记硫酸铵,研究上述作物对氮肥的利用率及氮在土壤中残留和损失。试验查明,按每100克土施氮8、16、32毫克计,马铃署对肥料氮利用率为77.1％,小麦为40.8％,其余作物为50％。当采用中等的施氮定额,即 The authors did field trials on gray forest soil and worked with pot experiments. The test crops are spring wheat, oats, barley, buckwheat, horse department, corn. The ~ (15) N-labeled ammonium sulfate was used to study the above-mentioned crop nitrogen use efficiency and nitrogen residual in the soil and loss. According to the test, at a rate of 8, 16 and 32 milligrams of nitrogen per 100 grams of soil, the utilization rate of nitrogen fertilizer by Fertilizers was 77.1%, that of wheat was 40.8% and that of the remaining crops was 50%. When using a medium nitrogen quota, that is