1978年以来,我们对水稻的吸肥动态以及不同时期追施氮肥对籽粒的作用进行了研究,同时也分析了穗肥施用时期对作物产量及品质的影响。应用示踪法研究这些课题,可以获得一般方法难于得到的有价值的材料,有助于阐明上述问题。1978年,我们在河北省芦台农场进行了水稻吸肥动态的研究;1978年及1979年,我们又在中国农科院原 Since 1978, we have studied the dynamics of rice absorption and the effects of topdressing nitrogen fertilizer on grains in different periods. We also analyzed the effects of top-dressing application on crop yield and quality. The use of tracer method to study these topics, can be obtained by the general method of valuable materials, help to clarify the above problems. In 1978, we conducted a study on the dynamics of rice absorption in Lutai Farm, Hebei Province. In 1978 and 1979, we again conducted research on the original Chinese Academy of Agricultural Sciences