黄丘区典型灌木和荒草地土壤含水量变化对降雨的响应

为了研究不同土地利用方式下土壤水分的变化特征及其对降雨的响应,以黄丘区辛店沟流域坡面径流小区灌木和荒草地为研究对象,利用多探头土壤水分监测仪对研究对象0—50 cm土层土壤水分进行了连续定位观测,对不同下垫面下土壤水分的变化特征进行了系统的分析和研究。结果表明:(1)不同土地利用方式土壤水分表现出明显的季节变化特征,观测期内荒草地的平均土壤含水量为0.099,大于灌木地0.091,荒草地的土壤含水量总体要高于灌木地。(2)不同土地利用方式土壤含水量垂直变化趋势相似,总体上随着土层深度的增加而减少,具有明显的垂直变异性,灌木地对深层土壤含水量的消耗比荒草地多。(3)土壤含水量在垂直方向上对降雨的响应程度随着土层深度的增加而减小,灌木地和荒草地垂直方向上0—30 cm土层与30—50 cm土层对降雨响应表现为相反的规律。研究认为相比荒草地,灌木地土壤水分消耗更严重,且深层土壤水分受降雨补给有限,易引发土壤干层。

Response of Soil Moisture of Typical Shrubland and Waste Grassland to Precipitation in the Loess Hilly-Gully Region

In order to study the variation characteristics of soil moisture and its response to precipitation in different land use patterns, the EM50 soil moisture data collector was used to continuously measure soil moisture in 0—50 cm soil layers of shrubland and barren grassland in slope runoff plot of the Xindiangou watershed in the loess hilly-gully region, and the variation characteristics of soil moisture in different underlying surfaces were systematically analyzed and studied. The results showed that:(1)the soil moisture of different land use patterns showed obvious seasonal variation characteristics; during the observation period, the average soil moisture of the barren grassland was 0.099, the average soil moisture of the shrubland was 0.091, and the soil moisture of the barren grassland was generally higher than that of the shrubland;(2)the vertical change trends of soil moisture in different land use patterns were similar, and generally decreased with the increase of soil depth, with obvious vertical variability; shrubland consumed more deep soil water content than barren grassland;(3)the vertical response of soil moisture to precipitation decreased with the increase of soil depth; the response of the 0—30 cm soil layer and 30—50 cm soil layer in the vertical direction of shrubland and waste grassland to precipitation was opposite. This research suggests that compared with waste grassland, shrubland consumes more soil moisture, and the deep soil moisture is limited by precipitation, which can easily lead to dry soil layers.