遮雨棚模拟黄土旱塬区降水变化对冬小麦生长及产量的影响

Influence of Shelter Simulated Precipitation Change on Growth and Yield of Winter Wheat in Loess Plateau in China

为了解降水变化对黄土旱塬区冬小麦生长及产量的影响,通过遮雨棚模拟冬小麦生长季减少30%降水(R-30%)、正常降水(CK)和增加30%降水(R+30%)情景,于2016-2018年研究了黄土旱塬区两季冬小麦土壤相对有效含水量、LAI、NDVI、生物量、产量及其构成的动态变化特征。结果表明,在降水正常的2016-2017年(降水距平百分率位于±15%以内),与CK相比,R-30%处理的土壤相对有效含水量在返青至抽穗期显著下降,冬小麦冠层NDVI显著降低,LAI和干物质增长速率明显变缓,冬小麦的穗数和千粒重显著降低,而R+30%处理下冬小麦LAI和干物质保持稳定增长优势。R+30%、CK和R-30%三种降水条件下冬小麦产量分别为4.66、3.12和2.43 t·hm-2,处理间差异显著。在降水偏多的2017-2018年(降水距平百分率超过30%),不同降水处理间土壤相对有效含水量、冬小麦LAI、冠层NDVI、生物量、产量及其构成等指标均未表现出显著差异。R+30%、CK和R-30%三个处理下冬小麦的产量分别为3.70、3.39和3.14t·hm-2,处理间差异亦不显著。因此,在正常降水年份,生长季增加30%降水可使冬小麦显著增产44.2%,减少30%降水可使冬小麦显著减产28.4%;在降水偏多年份,生长季降水增加30%或减少30%对冬小麦的生长及产量没有显著影响。

By using shelters to simulate 30% rainfall reduction(R-30%), normal rainfall(CK) and 30% rainfall increase(R+30%), we studied the changes of soil relative available water content, LAI, NDVI, biomass and yield for winter wheat within two growing seasons in Loess Plateau in China from 2016 to 2018. The results showed that the soil relative available water content declined rapidly;the NDVI decreased significantly;the LAI and biomass growth rate slowed down significantly, and wheat spike and 1 000-grain weight decreased significantly under R-30% treatment, in comparison with the CK treatment, in the normal precipitation of 2016-2017. Under R+30% treatment, LAI and biomass of winter wheat remained a steady growth advantage. Finally, the yield of winter wheat under R+30%, CK and R-30% treatments was 4.66, 3.12 and 2.43 t·hm-2, respectively. There were significant differences among all treatments. However, in wet year of 2017-2018, there was no significant changes in the soil relative available water content, LAI, canopy NDVI, biomass, yield and its components under different treatments. The yield of winter wheat under R+30%, CK and R-30% treatments were 3.70, 3.39 and 3.14 t·hm-2, respectively. Therefore, in normal precipitation year(530.2 mm precipitation), increasing precipitation by 30% can increase the yield of winter wheat by 44.2%, and decreasing precipitation by 30% can reduce the yield of winter wheat by 28.4%. In the wet years(713.9 mm precipitation), increasing 30% or decreasing 30% precipitation has no significant effect on growth and yield of winter wheat.