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~(15)N-尿素施于杂交稻的微区试验结果表明,施肥时间是影响尿素氮去向的一个重要因素。保花肥尿素氮回收率高达70.2％,残留率和亏缺率则仅为7.29％和22.6％。反之,基肥尿素氮的回收率、残留率和亏缺率分别为33.4％、22.7％和43.9％。在进入杂交稻地上部的尿素氮中约有72.1—85.1％分配在谷粒中。在本试验条件下,此比例有随尿素施用时间推迟而上升的趋势。残留氮中有94.1％保持在0—10cm土层中,这表明土壤对尿素有较强的吸附力,淋洗作用可能不是尿素损失的主要途径。在杂交稻生育期间,尿素激发效应引起土壤氮矿化增加量高于尿素氮残留量。后作小麦对于残留尿素氮的回收率仅5.6—18.7％。
~ (15) N-urea applied to hybrid rice in the micro-zone test results show that fertilization time is an important factor that affects the fate of urea nitrogen. Fertilizer urea nitrogen recovery rate as high as 70.2%, the residual rate and the deficit rate was only 7.29% and 22.6%. On the contrary, the recovery, residual rate and deficit rate of basal urea nitrogen were 33.4%, 22.7% and 43.9% respectively. About 72.1-85.1% of the urea nitrogen entering the upper part of the hybrid rice is distributed in the grain. Under the experimental conditions, this ratio tends to increase with the delay of urea application. 94.1% of the remaining nitrogen remained in the 0-10 cm layer, indicating that the soil has a strong adsorption capacity for urea, and the leaching action may not be the main route of urea loss. During the growth of hybrid rice, the effect of urea excitation caused soil nitrogen mineralization to increase more than urea nitrogen. After the wheat for residual urea nitrogen recovery of only 5.6-18.7%.