节水灌溉条件下氮肥对粳稻稻米产量和品质及氮素利用的影响

 以常规粳稻品种9325为材料，研究了大田条件下不同灌溉方式和氮素水平对水稻氮素利用及稻米产量和品质的影响。节水灌溉显著降低了单位面积有效穗数、整精米率、粗蛋白含量以及胶稠度，提高了垩白性状指标和直链淀粉含量，中高氮水平对产量影响不显著；同一灌溉方式下增施氮肥，显著提高了稻米整精米率、粗蛋白含量、垩白米率及垩白度，增加了胶稠度，减少了直链淀粉含量。节水灌溉下氮素干物质生产效率和氮素运转效率提高，氮素产谷效率则对水分反应不敏感；施氮量增加，水稻氮素积累总量及氮素转运效率与施氮量呈单峰曲线关系，随施氮量提高，氮素干物质生产效率、氮素产谷效率及氮素收获指数下降。

Effects of Nitrogen Application on Nitrogen Utilization and Grain Yield and Quality in Rice under Water Saving Irrigation

The effects of nitrogen fertilization levels on rice grain yield and quality were studied under different irrigation methods by using japonica rice cultivar 9325 as material. Under water saving irrigation, number of panicles per hectare, head rice rate, protein content and gel consistency of rice decreased, while chalkiness values and amylose content of rice increased. As the increase of N level, head rice rate, protein content, chalky grain rate, chalkiness and gel consistency improved, and amylose content decreased under the same water management. Under water saving irrigation, the efficiency of N utilization and translocation after heading increased, while N productivity insensitive to water. It was found that parabolic relationship existed between N applied rates and plant accumulation and translocation in rice. Increasing of N applied rates and N utilization resulted in decreasing N productivity and N harvest index. In addition, grain yield and rice quality were significantly related to variations of N absorption and utilization in respect to water management and N applied rates.