黄土丘陵区坡耕地与撂荒地土壤水分对降雨的响应特征

Abstract

为了揭示黄土丘陵区不同土地覆被方式下土壤含水量对不同强度降雨的响应过程，选取山西省冯家沟小流域农耕地和撂荒地为研究对象，基于2019年4-10月降雨和土壤含水量以小时为单位的观测数据，分析了土壤含水量对不同强度降雨的响应规律。结果表明：（1）小雨、中雨、大雨和暴雨对土层的影响深度分别为20、20、60 cm和60 cm，研究区降雨最主要的形式-小雨对土壤水分的补给作用较小。（2）各强度降雨过程中，除0-10 cm土层外，农耕地土壤含水量均大于撂荒地，且大雨条件下农耕地各土层土壤含水量变化较显著，而撂荒地仅0-10 cm和10-20 cm土层土壤含水量有所增加。（3）不同土层土壤含水量对降雨的响应不同，表层响应相对明显而深层相对减弱；农耕地土壤平均含水量最大值出现在50-60 cm土层，而撂荒地出现在30-40 cm土层。（4）本地区农耕地土壤含水量高于撂荒地，表明在该地区适当的作物种植有较好的储存土壤水分的作用。本研究的结果对地区水资源的高效利用和水土流失防控提供了一定的科学依据。;In order to reveal the response process of soil water content to different rainfall intensities under different land cover modes in Loess hilly region. This study selected the cultivated land and abandoned land in Fengjiagou small watershed of Shanxi Province as the research objects. Based on the observation data of rainfall and soil water content in hours from April to October 2019, the response of soil water content to different rainfall intensities was analyzed. The results showed that:(1) The influence depths of light rainfall, moderate rainfall, heavy rainfall and torrential rainfall on soil layer were 20, 20, 60 cm and 60 cm, respectively. The main form of rainfall-light rainfall had little effect on soil moisture in the study area. (2) During each rainfall intensity, except 0-10 cm soil layer, the soil water content of the cultivated land was higher than that of abandoned land, and the soil water content of each soil layer in the cultivated land changed significantly under heavy rainfall conditions, while the soil water content of abandoned land was only increased in 0-10 cm and 10-20 cm soil layers. (3) The content of soil water among soil layers had different response to rainfall, and the response of surface soil moisture was more responsive than that of the deep soil water content. The maximum average soil water content appeared in 50-60 cm soil layer in the cultivated land, while the abandoned land appeared in the 30-40 cm soil layer. (4) The soil water content of the cultivated land was higher than that of the abandoned land, indicating that appropriate crop planting in this region had a better role in storing soil moisture. The results of this study provide a scientific basis for the efficient utilization of regional water resources and the prevention and control of soil erosion.