利用￣（１５）Ｎ同位素示踪技术，研究了稻草和尿素配施时水稻对肥料和土壤氮的吸收。结果表明，稻草单施导致土壤速效氮的生物固定，氨素供应不足是影响水稻分蘖成穗的限制因子。稻草配合尿素施用，明显改善肥料氨和土壤氮的供应，既有利于当季水稻增产，也有利于培养土壤肥力，还有利于后茬作物产量的提高。 Using  (15) N isotope tracing technique, the nitrogen uptake by fertilizers and soil was studied when rice straw and urea were applied. The results showed that the single straw application resulted in the bioassay of soil available N, and the shortage of ammonia supply was the limiting factor that affected the tillering of rice. The combination of straw and urea significantly improved the supply of fertilizer ammonia and soil nitrogen, which is not only conducive to the increase of rice yield in the current season, but also to the cultivation of soil fertility, as well as to the improvement of the crop yield of the following crop.