氮硫配施对冬小麦籽粒灌浆特性及产量的影响

采用二元二次正交旋转组合设计，通过田间试验研究了关中地区氮硫配施条件下冬小麦籽粒灌浆特性及产量效应.结果表明：在氮硫配施条件下，小麦籽粒灌浆进程呈“慢 快 慢”的S型曲线.在N₂（108 kg·hm^-2）和N₄（267 kg·hm^-2）水平下，籽粒灌浆持续期、理论最大粒重和平均灌浆速率等籽粒灌浆参数均随施硫量的增加而下降；在S₂（97.5 kg·hm^-2）和S₄（202.5 kg·hm^-2）水平下，增加氮肥用量可以提高籽粒灌浆参数；而在N₃（187.5 kg·hm^-2）或S₃（150 kg·hm^-2）水平下，各灌浆参数随施硫量或施氮量的增加先升高后降低.花后25 d之前，各处理灌浆速率上升趋势相同；开花25 d后，各处理灌浆速率呈现不同的下降趋势.在N₃或S₃水平下，灌浆速率下降趋势随施硫量或施氮量的增加先减缓后加速.可见，适宜的氮硫配施水平能提高穗密度、延长有效灌浆时间、提高灌浆速率，从而增加籽粒产量.从肥料效应函数可得，在高施氮量（178.31～256.36 kg·hm^-2）和中等施硫量（131.95～167.65 kg·hm^-2）条件下，冬小麦产量可超过平均产量（3753 kg·hm^-2）.

Effects of N and S application on grain filling characteristics and yield of winter wheat.

A field experiment was conducted on the Guanzhong Plain, China, to evaluate the effects of N and S application on characteristics of winter wheat (cv. Xiaoyan 22) grain filling and yield, using a central composite rotatable design with two factors nitrogen (N) and sulfur (S). The results showed that, with the combined application of N and S, grain filling followed a “S” curve which increased slowly at first, then quickly, and then slowly again. With 108 and 267 kg N·hm^-2, the grain fill duration, theoretical maximum grain yield, and average filling rate decreased as the S application rate increased. With 97.5 and 202.5 kg S·hm^-2, N application improved grain filling parameter values. With 187.5 kg N·hm^-2 or 150 kg S·hm^-2, the parameters firstly increased, reached a maximum, and then decreased as the S or N input increased. Grain filling rate increased for 25 days following anthesis, and then declined at a rate that varied among treatments. When the N input was >187.5 kg·hm^-2 or the S input was >150 kg·hm^-2, the grain filling rate decreased with increasing the S or N input. The results also indicated that combined application of N and S fertilizers at appropriate rates could increase the head density and grain yield. Using the regression equations, highest grain yields estimates (≥3753 kg·hm^-2) were achieved with the combination of a high N rate (178.31-256.36 kg·hm^-2) and a moderate S rate (131.95-167.65 kg·hm^-2).