黄土高塬沟壑区两种乔木林土壤水分平衡的模拟

Simulations of Soil Water Balance in Two Arbor Forests Grown in Gully Region of the Loess Plateau

为了了解黄土高塬沟壑区不同乔木林的耗水规律,利用长期定位试验资料和Hydrus-1D模型详细研究了两种乔木林（侧柏林,刺槐林）的土壤水分动态变化及水量平衡各要素的差异。结果表明：结合优化的水力参数,Hydrus-1D模型能准确地模拟两种乔木林地土壤水分动态,模拟值与实测值均方根误差在0.018~0.029cm3/cm3之间,相对平均绝对误差在9.8%~12.5%之间;水分平衡各要素受气候和植物类型影响,蒸散量是水平衡中的主要支出项,侧柏林蒸散量占同期降水量的83.4%~108.4%,刺槐林蒸散量占同期降水量的75.9%~96.2%,生长季内刺槐林土壤储水量始终大于侧柏林。

In order to investigate the differences in water consumption of two arbor forests grown in the gully region of the Loess Plateau, Hydrus-1 D model coupling the long-term experimental data was used to simu- late the dynamics of soil water and soil water balance components in the sites grown Platyclatus orientalis and Robinia pseudoacacia. With the calibrated and validated hydraulic parameters, the Hydrus-1 D could be used to simulate soil water dynamics in two arbor forests. The root mean square errores between the simula- ted and measured water contents ranged from 0. 018 cma/cm3 to 0. 029 cma/cm3 , while the mean absolute rel- ative errores varied from 9.8% to 12.5%. The components of soil water balance were impacted by climatic conditions and tree species. Evapotranspiration was the largest one among all components of soil water bal- ance, which varied from 83.4% to 108.4% of total precipitation for Platyclatus oriental, and from 75.9% to 96.2% of total precipitation for Robinia pseudoacacia. With regard to the two trees, Robinia pseudoaca- cia had the larger soil water storage than Platyclatus orientalis during the study period from 2011 to 2013.