氮肥基追比和追氮时期对超高产冬小麦生育及产量形成的影响

Effects of basal-topdressing ratio and topdressing time of nitrogenon the growth and development and grain yield formation in superhigh yielding winter wheat

为明确氮肥运筹对超高产冬小麦生育特性和产量形成的影响,2010-2011年度在河北省藁城市以冬小麦品种‘石新828’为材料,在总施N 240kg/hm2条件下进行了氮肥基追比(3∶7、5∶5和7∶3)和春季追氮叶龄(春4、5和6叶期)的二因素裂区试验。结果表明:小麦各生育时期的LAI均随氮肥基追比增大而增大,尤其是拔节期不同基追比的LAI差异显著。随春季追氮时期后延,拔节到开花期的LAI减小,而开花20d以后的LAI显著增大。小麦旗叶总物质生产力在灌浆前期随氮肥基追比的减小和追氮时期的后延而下降,但在灌浆后期却随追氮时期的后延而增大。氮肥基追比对小麦产量和产量构成因素的影响均不显著。每公顷穗数随追氮时期后延显著减少,而每穗粒数和千粒重随追氮时期后延显著增加。籽粒产量也随追氮时期后延显著提高。综合研究结果,在总施氮量为240kg/hm2左右的条件下,河北省超高产冬小麦(9 000kg/hm2以上)的氮肥运筹以基追比5∶5～7∶3,春生6叶期追施氮肥最为适宜。

In order to clarify the effects of nitrogen regime on the growth and development and grain yield formation of winter wheat, a field experiment was conducted during 2010--2011 in Gaocheng county, Hebei province, China, with the winter wheat cultivar ＇Shixin 8287. The experiment was designed as split plot arrangement, with nitrogen basal-topdressing ratio as the main plots （including 3 ： 7, 5 ： 5 and 7 ： 3）, and nitrogen topdressing time as the split plots （at the 4th, 5th and 6th spring-born leaf stage, respectively） with total N 240 kg/hm2 applied. The results showed that, the LAI at all growth stages of winter wheat increased with the increasing of basal-topdressing ratio, especially the LAI at jointing stage was significantly different among the three basal-topdressing ratios. With the delay of nitrogen topdressing in spring, the LAI from jointing to anthesis decreased, but that after 20 days post-anthesis increased signifi- cantly. The biomass productivity of flag leaves reduced with the decrease of nitrogen basal-top- dressing ratio and the delay of nitrogen topdressing, but increased with delaying nitrogen top- dressing during the late grain filling period. The effects of nitrogen hasal-topdressing ratio on grain yield formation and yield components were all insignificant. The spikes per hectare de- creased insignificantly, but the grains per spike and 1 O00-grain weight of wheat increased with delaying nitrogen topdressing. Also, the grain yield of wheat increased with delaying nitrogen topdressing as a result of the interaction of the three yield components. According to the results, the optimum nitrogen regime for superhigh yielding winter wheat in Hebei province is the basal-topdressing ratio 5 ： 5 to 7 ： 3 and topdressing at the 6th spring leaf stage with total N 240 kg/hm2 applied.