人工柠条林地土壤水分补给和消耗动态变化规律

Dynamics of Soil Water Supply and Consumption in Artificial Caragana Shrub Land

黄土高原地区水资源缺乏，水资源，特别是土壤水资源的适度开发和合理利用势在必行。在黄土丘陵半干旱区的上黄生态试验站对多年生人工柠条林林冠截留，地表径流，土壤水分和植物生长等进行了定位观测，对林地土壤水分补给和消耗动态变化规律进行分析。结果表明，人工柠条林次降雨林冠截留随降水量增加而逐渐增加，地表径流与林外降雨量为直线关系。影响土壤水分补给的主要因素为天然降水，其次为林冠截留。土壤水分补给量与降雨量为线性关系；降水对土壤水分的影响程度随深度的增加而减弱，土壤水分最大入渗深度为170～270cm。偏早年随着柠条林生长并进入速生期，柠条林地耗水量加大，土壤早化加剧。丰水年土壤补给量剧增，但柠条林依然生长不良，储存在土壤中的水分只能等到来年被植物吸收利用。

The water resource is short, and rational utilization of water resource, especially soil water resource is imperative on the Loess Plateau. The canopy interception, runoff, soil water and plant growth was measured and soil water supply and soil water consumption was analysed in the perennial artificial Caragana shrub land in the Shangshong eco-experiment station of Loess Plateau. The results showed that canopies＇ interception increase with rainfall. The runoff relation of rainfall outside forest is linear. The first factor influencing soil water is precipitation, second is canopy interception. The relationship between rainfall and soil water supply is linear. The impact of rainfall on soil water was reduced with depth decrease. The largest depth of wetting by rainfall is 170 cm in 270 cm in 2004. Along with Caragana forest start to bud and fall into fast growth period, soil water consumption was increased gradually, and soil drying was intensitied in light drought year. The soil supply increase fast and soil water storage increased, but the soil water would be used by plant by the next year in rainy year.