秸秆全量还田对冬小麦不同小穗位和粒位结实粒数和粒重的影响

 【目的】研究小麦玉米秸秆连续全量还田对小麦穗部不同小穗位和粒位结实粒数及粒重变化的影响。【方法】通过设置3年定位试验研究小麦玉米秸秆全量还田对小麦不同小穗位结实粒数、粒重的小穗位和粒位的影响效应。【结果】小麦玉米秸秆连续全量还田提高了小麦的公顷穗数、穗粒数、千粒重和产量。各处理小麦不同小穗位结实粒数、小穗重、小穗平均单粒重均呈现二次曲线变化趋势，不同粒位的粒重也随小穗位的变化呈二次曲线形式。结实小穗越多、各小穗结实粒数或单粒重差异越小，空间分布模拟曲线的弧度越平缓。秸秆还田提高了小麦主茎穗和分蘖穗的结实小穗数与小穗结实粒数，降低了不孕小穗数，且下部小穗的结实粒数增加幅度较大；秸秆还田还提高了小麦不同粒位的单粒重，以第3、4粒位提高幅度较大。【结论】小麦玉米秸秆连续全量还田提高了小麦不同小穗位的结实粒数和粒重，进而提高了籽粒产量。

Effects of All Straw Returned to the Field on Grain Number and Grain Weight at Different Spikelets and Grain Positions in Winter Wheat

【Objective】 The objectives of this study were to research the change of gain number and grain weight of wheat with spikelet and grain position in main stem and tiller spike under the condition of straw returned to the field. 【Method】 A location field experiment was conducted from 2008 to 2010, single maize straw returned to the field, single wheat straw returned to the field, wheat and maize straw returned to the field were conducted to study the effects of straw returned to the field on grain number and grain weight at different spikelets and grain positions in winter wheat. 【Result】Results showed that, the spike per hectare, grain number per spike, 1 000-grain weight and yield were increased in treatment of straw returned to the field. The distribution of grain number, spikelet weight, and grain weight with the spikelets positions showed parabolic changes, so as the grain weight at 1st, 2nd, 3rd in each treatment and 4th in treatment of straw returned to the field. The more fertile spikelet number and less difference in spikelet grain number and single grain weight, the smoother the parabola was. The fertile spikelet number and spikelet grain number in main stem and tiller spike were increased in treatment of straw returned to the field, the increase range of fertile spikelet number in the bottom spikelet were bigger. There were different increasing effects of straw returned to the field on single grain weight at different grain positions, especially for at of 3rd and 4th grain position. 【Conclusion】 Therefore, under the condition of wheat and maize straw returned to the field, grain yield and yield components, spikelet grain number and grain weight at different spikelets of wheat were enbanced.