陕北黄土区陡坡微地形土壤水分对降雨的响应

Response of soil moisture of steep slope micro-topography to rainfall in loess region of northern Shaanxi

土壤水分是制约陕北黄土区陡坡林草植被建设的主要因素,降雨是该区域土壤水分的主要来源,微地形可对降雨进行二次分配影响土壤水分,因此,研究陡坡微地形土壤水分对降雨的响应,可为该地区林草植被建设植物群落结构配置提供理论依据。以原状坡作为对照,采用聚类分析法对微地形土壤水分垂直变化进行分层以及Pearson相关系数分析各微地形不同剖面土壤水分与降雨的相关关系,揭示各微地形土壤含水量对降雨的响应差异。结果表明:0~20cm缓台和切沟土壤水分对降雨的响应达到极显著水平(P<0.01),浅沟达到显著水平(P<0.05);40~100cm切沟达到显著水平(P<0.05);100~120cm切沟达到极显著水平(P<0.01);120~140cm切沟达到极显著水平(P<0.01),塌陷达到显著水平(P<0.05);140~160cm塌陷和陡坎达到极显著水平(P<0.01),切沟达到显著水平(P<0.05)。

Soil moisture is the main factor restricting the steep slope vegetation construction of northern Shaanxi loess area,rainfall is the main source of soil moisture in this area,while micro topography affects soil moisture through secondary distribution of rainfall.Therefore,the study of the response of tiny terrain steep slope soil moisture to rainfall could provide theory basis for plant community structure configuration in the regional vegetation construction.Taking the undisturbed slope as the control,the vertical variation of soil moisture in the micro-topography was stratified by cluster analysis method,and the correlation coefficient of Pearson was used to analyze the correlation between soil moisture and rainfall in different sections of the micro-topography,so as to reveal the response difference of soil moisture in each micro-topography to rainfall.The results showed that the response of soil moisture to rainfall was as follows:the response of that of 0-20 cm in platform and gully reached extremely significant level(P<0.01),while that in shallow gully reached significant level(P<0.05).Gully of 40~100 cm reached a significant level(P<0.05).Gully of 100~120 cm reached extremely significant level(P<0.01).The collapse of 120-140 cm reached significant level(P<0.05),and the gully reached extremely significant level(P<0.01).Collapse and scarp of 140~160 cm reached extremely significant level(P<0.01),and gully reached significant level(P<0.05).