次降雨后不同时段坡地表层土壤水分和容重的空间变异特征

Spatial Variability of Surface Soil Moisture and Bulk Density in a Slope-land at Different Stages After a Rainfall

采用经典统计学方法,通过网格布点,研究黄土高原坡地表层土壤水分和容重在降雨后不同时段的空间变异特征。结果表明:(1)降雨后第1天,表层土壤水分和容重的变异程度分别为中等、弱变异性;在各坡向间土壤水分呈阴坡>阳坡>山脊的变化趋势,容重为阴坡>山脊>阳坡;(2)降雨后第20天,土壤水分和容重的变异程度均保持不变,但土壤水分在不同坡向间的数量特征发生改变(阴坡>山顶>阳坡),而容重的变化趋势保持不变;(3)表层土壤水分具有弱的时间稳定性,而容重的时间稳定性较强。(4)相关分析表明,降雨后第1天,山脊上的土壤水分与容重具有极显著的负相关关系(P<0.01),而降雨后第20天,阴坡土壤水分(容重)与山顶土壤水分呈显著正(负)相关(P<0.05)。相关结果可为黄土高原坡地水分管理、水土过程调控提供参考。

Spatial variation characteristics of surface soil moisture（SSM） and bulk density（BD） at different stages after a rainfall were studied in a typical slope-land of the Loess Plateau,by means of classical statistics with grid sampling strategy（10 m ×10 m）.SSM and BD were measured using oven-drying and ring knife method,respectively.Results showed that（1）At the first day after the rainfall,SSM and BD indicated a medium and weak variation extent,respectively.Among different slope aspects,the sequence of SSM and BD were： Lunar slopesunshine sloperidge,and lunar sloperidgesunshine slope,respectively.（2）At the 20th day after the rainfall,the variation extent of SSM and BD did not change.However,among the slope aspects,the distribution of SSM became as lunar sloperidgesunshine slope,while BD kept stability.（3）The spatial distribution of SSM demonstrated weak time stability,while BD played relative strong time stability.（4）Correlation analysis showed that SSM negatively correlated with BD（P0.01） on the ridge at first day after rainfall.While,SSM（BD） in lunar slope were positively（negatively） correlated with SSM in mountaintop（P0.05）.A better understanding of these results was benefit to the soil water management and mediation of slope-land on the Loess Plateau.