氮肥减量后移对华南双季稻产量和氮肥利用率的影响

Grain Yield and Nitrogen Utilization Efficiency of Double-cropping Rice in Response to Reduced and Delayed Application of Nitrogen in South China

【目的】通过氮肥减量和后移提高水稻的产量和氮肥利用率。【方法】2014年早季、晚季,设置不施氮肥(T1)、习惯施肥法(对照,T2)和2个氮肥减量后移处理〔三控施肥法(T3)、氮肥重度后移(T4)〕共4个处理,测定水稻群体动态、物质生产、产量和氮肥吸收利用等指标。【结果】与T2处理相比,早季T3、T4处理稻谷产量分别增加8.8%和12.0%,晚季分别增加12.7%和18.4%。早晚两季,T3、T4处理总吸氮量、氮肥吸收利用率、农学利用率和氮肥偏肥生产力均较T2处理显著提高。T3、T4处理水稻生长和氮素吸收在穗分化前比T2处理缓慢,此后则大幅加快。T3、T4处理分蘖成穗率较T2处理分别提高5.5~6.8、18.3~19.4个百分点。与T2处理相比,抽穗期T3、T4处理叶面积指数分别增加11.5%和35.4%,叶片含氮量分别提高27.7%和50.8%;早季库容分别扩大12.7%和19.4%,晚季库容分别扩大18.3%和47.6%。与T3处理相比,T4处理产量早季、晚季分别增加3.0%和5.0%,分蘖成穗率分别提高11.5、13.9个百分点,抽穗期叶面积指数和叶片含氮量分别增加21.5%和18.1%,库容分别扩大6.0%和24.8%,但结实率和千粒质量都下降,氮肥农学利用率分别提高8.0%和26.0%。【结论】氮肥减量后移使水稻源和库显著扩大,产量和氮肥利用率显著提高。

【Objective】The amount of nitrogen(N)application was reduced and topdressing was delayed to further enhance N utilization efficiency and grain yield of rice.【Method】In the early and late cropping seasons of 2014,comparison trials were conducted with 4 treatments,including zero applied N(T1),farmer’s practice(T2),“Three-Control”technology with moderate-delayed N topdressing(T3),and highly-delayed N topdressing(T4).Tillering dynamics, growth,grain yield and N utilization efficiency of rice were determined.【Result】In comparison to that under T2,the grain yields under T3 and T4 were increased by 8.8%and 12.0%in early season(ES)or by 12.7%and 18.4%in late season(LS),respectively.In both seasons,the total N uptake amount,N utilization efficiency,agronomic utilization efficiency and partial fertilizer productivity of T3 and T4 were increased significantly compared with those of T2.The nitrogen uptake and growth of plants under T3 and T4 were roughly slower than those under T2 before panicle initiation and they were both getting faster afterwards.Compared with T2,leaf area index(source size)under T3 and T4 was increased by 11.5%and 35.4%and leaf nitrogen content was enhanced by 27.7%and 50.8%at heading.The productive tiller rate(in absolute term)was enhanced by 6.8%and 18.3%in ES or by 5.5%and 19.4%in LS.Sink size was enlarged by 12.7%and 19.4%in ES or by 18.3%and 47.6%in LS.In comparison to that under T3,the grain yield under T4 was increased by 3.0%and 5.0%in ES and LS,the productive tiller rate was enhanced by 11.5%and 13.9%,the leaf area index and leaf nitrogen content were enhanced by 21.5%and 18.1%at heading stage and sink size was enlarged by 6.0%and 24.8%,respectively,but both grain filling rate and 1000-grain weight were reduced moderately.The agronomicl efficiency of nitrogen was enhanced by 8.0%and 26.0%,respectively.【Conclusion】Under the reduced and delayed N applications,both source and sink of rice were enlarged dramatically,and the grain yield and nitrogen utilization efficiency were enhanced substantially.