【目的】秸秆还田不仅可改良土壤和增加土壤有机质,还能提高作物产量和品质。但秸秆还田后,土壤有机酸积累和微生物固氮,抑制水稻前期生长。在长江流域稻麦两熟地区,当地农户往往通过增加施氮量来解决秸秆还田的负效应,造成肥料浪费和氮污染。因此,探索研究秸秆还田条件下水稻优化的氮肥运筹措施,阐明水稻产量形成和氮素吸收与利用对氮素响应特征,对于提高水稻产量和氮素利用效率具有重要意义。【方法】2012 2013年,以超级粳稻武运粳24号和宁粳3号为材料,在江苏省兴化市进行大田试验,在秸秆全量还田条件下,设置常规施氮300 kg/hm2(N1)、增加施氮量345 kg/hm2(N2)和常规施氮运筹(CFP,基肥∶分蘖肥∶穗肥=3∶3∶4)、改进施氮运筹(MFP,基肥∶分蘖肥∶穗肥=4∶3∶3),以无氮处理为对照,研究施氮量和氮肥运筹措施对水稻产量及其产量构成、干物质积累、氮素积累、氮素吸收速率和氮肥利用效率的影响。【结果】随着氮肥水平提高,水稻穗数显著增加,每穗粒数、结实率和千粒重下降,最终增产不显著。与常规施氮运筹比较,改进氮肥运筹显著增加穗数,显著提高群体颖花量并增产,在N1水平下,改进施氮运筹增产幅度为5.18%7.10%,高于N2水平的2.70%4.29%。随着施氮量增加,水稻分蘖中期、拔节期、移栽期至分蘖中期、分蘖中期至拔节期干物质积累量、氮素积累量显著增加,最终成熟期干物质积累量和氮素积累量有所增加,但差异不显著,而氮肥农学利用率、氮肥吸收利用率和氮偏肥生产力显著下降。与常规氮运筹处理相比,改进氮运筹显著增加水稻移栽期至分蘖中期干物质积累量、氮素积累量和氮素吸收速率,增加成熟期干物质积累量和氮素积累量,提高氮肥农学利用率、氮肥吸收利用率、氮肥生理利用率和氮偏肥生产力,在N1水平下成熟期干物质积累量和氮素积累量分别增加6.52%和5.55%,氮肥农学利用率、氮肥吸收利用率、氮肥生理利用率和氮偏肥生产力分别提高13.36%、8.55%、4.44%和5.29%,差异均达显著水平。【结论】秸秆全量还田条件下,增加氮肥用量水稻增产不显著,且氮肥利用效率低。不增加氮肥用量,通过适当提高基肥比例(基肥∶分蘖肥∶穗肥=4∶3∶3),可实现提高水稻产量、干物质积累量、氮素积累量和氮肥利用效率。 【Objective】 Straw returning can not only improve soil and increase soil organic matter, but also improve crop yield and quality. However, after returning straw to soil, the organic acid accumulation in soil and nitrogen fixation by microorganisms inhibited the growth of rice in the early stage. In the rice-wheat two-cropping areas in the Yangtze River basin, local farmers often solve the negative effect of returning straw to soil by increasing the amount of nitrogen applied, causing fertilizer waste and nitrogen pollution. Therefore, it is of great significance to explore the optimum nitrogen application strategy for rice under straw mulching condition, to elucidate the response of nitrogen production to rice yield formation and nitrogen uptake and utilization, and to improve the rice yield and nitrogen use efficiency. 【Method】 In 2013 and 2013, the super japonica rice Wuyunjing 24 and Ningjing 3 were used as materials in the field experiment in Xinghua City, Jiangsu Province. Under the conditions of total straw returning to soil, conventional nitrogen application rate of 300 kg / hm2 N1, nitrogen application rate 345 kg / hm2 (N2) and conventional nitrogen application (CFP, basal fertilizer: tillering fertilizer: panicle fertilizer = 3: 3: 4) Fertilizer = 4: 3: 3). The effects of nitrogen application rate and nitrogen fertilizer application on rice yield, yield components, dry matter accumulation, nitrogen accumulation, nitrogen uptake and nitrogen use efficiency . 【Result】 With the increase of nitrogen fertilizer level, the panicle number of rice significantly increased, the number of grains per panicle, seed setting rate and grain weight per panicle decreased, but the yield was not significant. Compared with the conventional nitrogen application, improved nitrogen fertilizer application significantly increased the spike number, significantly increased the population spikelet yield and increased yield. Under the N1 level, the improved nitrogen fertilizer application yield was 5.18% 7.10%, higher than the N2 level of 2.70% 4.29% . With the increase of nitrogen application rate, dry matter accumulation and nitrogen accumulation at mid tillering stage, jointing stage, transplanting stage to tillering stage, middle tillering stage to jointing stage were significantly increased, dry matter accumulation and nitrogen accumulation However, the difference was not significant, but the agronomic efficiency of nitrogen fertilizer application, N fertilizer use efficiency and nitrogen partial fertilizer productivity decreased significantly. Compared with the conventional nitrogen management, improved nitrogen application significantly increased the dry matter accumulation, nitrogen accumulation and nitrogen absorption rate during the transplanting to the tillering stages, increased the dry matter accumulation and nitrogen accumulation in maturity, and increased nitrogen fertilizer Agricultural utilization, nitrogen absorption and utilization, nitrogen utilization efficiency and nitrogen partial fertilizer productivity, dry matter accumulation and nitrogen accumulation increased by 6.52% and 5.55% respectively at the N1 level, N fertilizer use efficiency, N fertilizer use efficiency The rates of physiological nitrogen use efficiency and nitrogen partial fertilizer productivity increased by 13.36%, 8.55%, 4.44% and 5.29%, respectively, with significant differences. 【Conclusion】 Under the condition of straw returning to full field, the yield increase of nitrogen fertilizer was not significant, and the nitrogen use efficiency was low. Without increasing the amount of nitrogen fertilizer, the yield, dry matter accumulation, nitrogen accumulation and nitrogen use efficiency can be increased by appropriately increasing the ratio of basal fertilizer (basal fertilizer: tillering fertilizer: panicle fertilizer = 4: 3: 3)