Sandy Soil Evaporation beneath the Canopy of Poplar Plantation in Yongding River Basin | 永定河沿河沙地杨树人工林林下土壤蒸发研究

صينى. 【目的】探讨沙地杨树人工林林下土壤蒸发的变化特征及规律。【方法】以永定河沿河沙地杨树人工林为研究对象，通过称重法测定其林下土壤蒸发量，同时应用主成分法和回归分析法分析各环境因子对土壤蒸发的影响。【结果】2010～2011年生长季内土壤蒸发量分别为155.4mm和209.8mm，分别占同期降雨量的42.4%和41.5%。影响土壤蒸发的主要因子为土壤水分、土壤温度、大气因子，当土壤水分条件较差时，土壤蒸发与土壤温度和大气因子之间的关系不显著。【结论】沙地杨树人工林林下土壤蒸发作用较强，并且主要受到土壤水分的限制，同时大气因子和土壤温度对其也有不同程度的影响。

إنجليزي. 【Objective】 The objective of this study was to find out the trends and properties of sandy soil evaporation beneath the canopy of poplar plantation. 【Method】 A weighing method was used to measure daily soil evaporation in a poplar plantation on the flood plain of Yongding river. The relationships between soil evaporation and environmental factors were detected through statistic methods including principal components and regression analysis. 【Results】 Soil evaporation during the growing season in 2010 and 2011 were 155.4mm and 209.8mm respectively, consuming 41.5%～42.4% of precipitation in the corresponding period. Soil water content, soil temperature, and atmosphere factor were the major factors that affected the change of soil evaporation. But the coupling relationship between atmosphere and soil evaporation was weaken when the soil water was poor. 【Conclusion】 Sandy soil evaporation beneath canopy was relatively strong. It was mainly affected by soil water condition, but also reacted to the changes of atmosphere factor and soil temperature.