水稻植株对氮的回收率是相当低的。施用标记氮肥作基肥表施的回收率最低为7—38％。采用分期施氮的回收率可达35—61％,而迟施或深施氮肥的回收率分别是27—77％与18—68％。在氮素平衡试验中,可以间接计算土壤——作物体系中氮的损失。氮肥表施损失可达16—51％;深施损失为7—37％。其损失系由以下原因所引起: 挥发:所施氮素由于挥发的损失可达 Rice plant nitrogen recovery is quite low. The lowest rate of application of labeled nitrogen fertilizer for basal application was 7-38%. The recovery of nitrogen by staging can reach 35-61%, while the recovery rate of late or deep application of nitrogen fertilizer is 27-77% and 18-68% respectively. In the nitrogen balance test, the loss of nitrogen in the soil-crop system can be calculated indirectly. Topdressing nitrogen fertilizer up to 16-51%; deep facilities for the loss of 7-37%. Its loss is caused by the following reasons: Volatilization: The applied nitrogen is up to the loss due to volatilization