模拟降雨条件下谷子和冬小麦植株对降雨再分配过程的影响

Effect of millet and winter wheat planting on the redistribution of rainfall under simulated rainfall conditions

以谷子(Setaria italica)、冬小麦(Triticum aestivum Linn.)为研究对象,利用人工模拟降雨测定了不同降雨强度和生长阶段两种作物植株的穿透雨,采用人工喷雾法测定了不同生长阶段的冠层截留,根据水量平衡法计算了不同观测阶段的茎秆流。结果表明:谷子、冬小麦冠层对降雨的再分配作用显著,谷子冠下穿透雨率平均约为79%,茎秆流率平均约为20%,冠层截留率平均约占1%;冬小麦冠下穿透雨率平均约为79%,茎秆流率平均约为19%,冠层截留率平均约占2%。在其全生育期内,两种作物冠下穿透雨与茎秆流呈彼此消长趋势。穿透雨量和茎秆流量与降雨强度呈显著正相关关系,但是穿透雨率和茎秆流率与降雨强度的关系不显著。茎秆流量和冠层截留量及其二者占总降雨量的比率均与作物叶面积指数呈显著正相关关系,但穿透雨量及穿透雨率随叶面积指数增加呈显著下降趋势。

Effect of crop canopies on the reallocation of rainfall plays an important role in exploring the influence of crops on the formation and development of soil erosion in sloping fields ,which has important significance for revealing the mechanism of crops affecting soil erosion as well as using agricultural water reasonably and effectively .The study aims to determine the through fall of two crops ,millet and winter wheat ,during different growth periods under different rainfall intensity .Based on the rainfall simulation experiment ,canopy interception in different growth periods was determined with the artificial spray method ,and stem flow was calculated by water balance .The results showed that rainfall realloca-tion was significantly affected by canopies of millet ,with the mean through fall rate of 79% ,the mean stem flow rate 20% ,and the mean canopy interception rate 1% .Winter wheat showed the similar trend ,with the mean through fall rate being 79% ,the mean stem flow rate 19% ,and the mean canopy interception rate being 2% .For the whole growth period ,there was a opposite trend between the through fall and flow of stem of two crops under canopies .There was a significant positive correlation between through fall capacity or stem flow capacity and rainfall intensity ,but there was no significant correlation between through fall rate or stem flow rate and the rainfall intensity .There was a positive correla-tion among stem flow and canopy interception as well as the proportion of both in the total rainfall capacity ,but through fall capacity and through fall rate both decreased with the leaf area index increased .This finding could lay the foundation of improving water use efficiency and reducing soil erosion .