黄土高原水蚀风蚀复合区人工植被土壤水分状况

采用烘干法及WP4水势仪对黄土高原水蚀风蚀复合区人工林下土壤重量含水量及水势进行测定,从土壤水分数量和能量两方面分析该区土壤水分时空分布和动态变化特征,并且通过实测数据对不同树种土壤水分特征曲线进行拟合,旨在为该区今后植被建设及生态用水提供理论参考。结果表明,各树种在0-300 cm土层土壤含水量随深度增加而逐渐降低,并趋于稳定。0-30 cm土层土壤含水量变化剧烈,30 cm以下土层土壤含水量逐渐降低,并趋于稳定在3.00%~5.00%。土壤水分受降雨量及其分配影响显著,观测期内土壤储水量盈余26.7 mm。土壤水势与土壤含水量变化规律一致,土壤水分特征曲线拟合结果较好。在丰水年,降雨只对浅层土壤水分起到补给作用,深层土壤水分亏缺严重,存在土壤干层。在特殊降水年份对该区土壤水分进行研究具有重要意义。

Soil Moisture of Artificial Vegetation in Mixed Area with Water and Wind Erosion of Loess Plateau

The soil moisture and water potential of artificial vegetation in the mixed area with water and wind erosion of the Loess Plateau has being measured by the stove method using WP4 Dewpoint Potential Meter.The research analyzed the characters of spatial and temporal distribution and dynamic change of soil moisture from both volume and energy side,calculated the soil water retention curve of different species trees based on real data.The results would provide the necessary theoretical reference for the vegetation construction and ecological water requirement.The result indicated that,with the depth increasing,the soil moisture decreased to stabilization in 0-300 cm soil layer.Soil moisture markedly changed in 0-30 cm soil layers,but soil moisture gradually decreased to stabilization at the 3.00%~5.00% below 30 cm soil layer.Soil moisture was significantly affected by the precipitation and its distribution,and in the observation period soil water reserved 26.7 mm.Soil water potential and soil moisture changed consistently,all correlation coefficients were over 0.95,and the results of soil water retention curve fitting were better.In the high-flow year,rainfall supplied moisture to the soil of shallow layer,but the soil of deep layer was seriously short of moisture.There were dried earth layers in the deep soil layer.It is of great significance to pay more attention to the soil moisture in the special rainfall years.