不同施氮水平下缓释氮肥配施对机插稻氮素利用特征及产量的影响

【目的】在高施氮水平和常规施氮水平下,研究缓释氮肥配施对机插稻氮素利用和产量的影响及其生理机制,为机插稻的氮肥高效利用提供依据。【方法】以中迟熟杂交籼稻川谷优7329为材料,采用二因素裂区设计,设置不同的施氮水平及5种缓释氮肥与常规氮肥(尿素)配施处理,并设置不施氮处理,分析不同施氮水平下缓释氮肥与常规氮肥配施对机插稻氮素利用和产量的影响及其生理机制,并探讨氮素利用和产量与生理响应之间的关系。【结果】结果表明,施氮水平、缓释氮肥与常规氮肥配施对机插稻氮素利用特征及产量均存在显著或极显著的影响,机插稻拔节、抽穗及结实期对氮素的吸收利用以及结实期茎鞘的氮素转运量与干物质量、氮素积累量、氮肥表观利用率、每穗实粒数及最终产量显著或极显著正相关(r=0.38*~0.69**)。与常规氮肥运筹相比,缓释氮肥与常规氮肥配施、全缓释氮肥施用处理的机插稻成熟期干物质积累量、氮素积累总量、光合势、叶面积指数、氮肥表观利用率及穗部氮素增加量均显著提高,进而促进增产。【结论】据产量及氮素利用效率表现,机插稻产量在180 kg/hm2施氮水平下较高,且在缓释氮肥与常规氮肥配施比例为7∶3一次性施用时产量最高,较其他氮肥运筹产量高0.84%~26.59%,氮肥表观利用率高0.28%~47.02%,为最优氮肥运筹模式。但不同施氮水平下,随着缓释氮肥配施比例的降低,群体叶面积指数、光合势及物质积累等指标也降低,且在施氮处理为全常规氮肥时最低,均不利于机插稻氮肥利用效率及最终产量的提高。

Effects of Slow release Urea on Nitrogen Utilization and Yield in Mechanically transplanted Rice under Different Nitrogen Application Rates

【Objective】Effects of different nitrogen (N) application rates (150 kg/hm2 and 180 kg/hm2) and slow release urea on N utilization and grain yield and its physiological characteristics in mechanical transplanted rice were studied to lay a scientific base for high efficient N utilization in mechanical transplanted rice.【Method】 Hybrid rice Chuanguyou 7329 was used to investigate the effects of nitrogen (N) application rates and various slow release urea ratios to conventional urea, (10∶0, 7∶3, 5∶5, 3∶7 and 0∶10, respectively) on N utilization efficiency (NUE), grain yield and its physiological characteristics of mechanical transplanted rice, as well as the correlation between N utilization， grain yield and physiological characteristics. 【Result】The results showed that N application rates and slow release urea combined with conventional urea had significant effects on NUE and grain yield. The N utilization at jointing, heading, and filling stage, and the N translation amount of stem sheath during filling stage had a significant positive correlation with dry matter weight, N accumulation, N apparent use efficiency, spikelet number per panicle and grain yield. Compared with conventional urea, slow release urea or slow release urea combined with conventional urea could significantly increase dry matter accumulation, N accumulation, photosynthetic potential, leaf area index (LAI), N apparent use efficiency, and N increment of panicle in mechanical transplanted rice. 【Conclusion】According to grain yield and NUE, the higher grain yield and NUE were obtained at the N application rate of 180 kg/hm2, especially at the ratio of slow release urea to conventional urea 7∶3, 0.84%-26.59% and 0.28%-47.02% higher than that of other treatments, respectively. This treatment could also enhance the NUE and grain yield, which was the optimum N management in this experiment. Moreover, LAI, photosynthetic potential and dry matter accumulation decreased with the decline of the proportion of slow release urea, and these indexes were the lowest in the treatment of whole conventional urea, which were not conducive to NUE and grain yield of mechanical transplanted rice.