降雨对秸秆还田玉米地土壤水分空间变异性的影响

Influence of Rainfall on Spatial Variability of Soil Moisture in Corn Farmland Under Straw Return Condition

基于TDR测量的黑土区玉米地土壤水分,应用多重分形等理论研究土壤水分空间变异特征对降雨的响应.结果表明:降雨前后土壤水分均为中等变异;相对于降雨前,降雨后不同土层土壤水分空间相关范围、空间相关程度和空间变异程度随时间的变化特征有所差异;降雨前后0~20cm土层空间变异性主要由其低值造成,其他土层主要由其高值引起;降雨前与降雨后第一天土壤水分的多尺度相关程度,小于与降雨后第二天的多尺度相关程度;与降雨前土壤水分空间相关范围、空间相关程度、空间变异程度及相邻土层土壤水分多尺度相关程度随土层深度增加的变化特征相比,除降雨后第一天空间变异程度、第二天空间相关范围的变化特征与降雨前不同外,降雨后第一天和第二天其他上述特征参数的变化特征与降雨前相同.

Based on soil moisture measured with TDR,influence of rainfall on spatial variability of soil moisture in corn field was studied with multifractal and other methods.The results showed that soil moisture before and after rainfall had moderate variability;compared to spatial correlation range,spatial correlation degree and spatial variability degree of soil moisture before rainfall,after rainfall,change characteristics of above parameters in different soil layers were different with time;spatial variability of soil moisture in the 0-20 cm soil layer before and after rainfall were mainly brought about by its low values,and those in the other soil layers were mainly caused by its high values;multi-scale relationship degrees between soil moisture before rainfall and on the first day after rainfall were less than the ones before rainfall and on the second day after rainfall;compared to the trends of spatial correlation range,spatial correlation degree,spatial variability degree and multi-scale relationship degree between soil moisture in adjacent soil layers before rainfall with the increasing of soil layer depth,except the trends of spatial variability degree on the first day and spatial correlation range on the second day after rainfall were different from the ones before rainfall,and the trends of other aforementioned parameters on the first and second days after rainfall were identical to the ones before rainfall.