林地土壤水分模型SWUF在晋西黄土高原的适用性

采用EnviroSMART土壤水分定位监测系统于2008-05-14至2008-10-11及2009-05-05至2009-08-05对晋西黄土区刺槐人工林、油松人工林(水平条整地)、天然次生林0～150cm土层的土壤水分进行实时监测。以这些监测数据为基础,分析SWUF模型参数的敏感性,进行参数率定,验证SWUF模型在晋西黄土高原水土保持林地的适用性。结果表明:SWUF模型中的蒸发参数、产流参数、非饱和水流参数属于高度敏感性参数,使用SWUF时必须对这些参数进行率定;SWUF模型对刺槐人工林20～150cm各土层、油松人工林和次生林0～150cm各土层土壤水分动态模拟效果较好,模拟值与实测值相对误差在20%以内;SWUF适用于模拟油松人工林和天然次生林各土层每日土壤含水量,也能够比较充分地模拟3种林地不同深度土壤层土壤水分的日变化趋势,但在模拟耗水量大的刺槐林表层土壤水分方面还需要改进。

Applicability of the SWUF Model on the Hilly Loess Plateau in Western Shanxi Province

Study on soil water is crucial to construction and management of the water and soil conservation forests on the Loess Plateau. Dynamics of soil water from the 0-150 cm layers in three types of forests (Robinia pseudoacacia and Pinus tabulaeformis (on a terraced field) plantations, and a naturally regenerated secondary forest) were monitored in this study with an EnviroSMART monitoring system (from 2008-05-14 to 2008-10-11 and from 2009-05-09 to 2009-08-08). The collected data were used to analyze the sensitivity and calibrate parameters of SWUF model, and this paper evaluated the applicability of SWUF model on hilly Loess Plateau in western of Shanxi Province. The results revealed that the simulated soil moisture was considerably sensitive to evaporation parameter, runoff parameter, and unsaturated flow parameters. Calibration of these parameters is necessary to apply SWUF model in this study area. The SWUF well simulated the daily average soil water content of each layer from 20-150 cm depth in R. pseudoacacia plantation and from 0-150 cm depth in P. tabulaeformis plantation and the secondary forest and the absolute relative error (ARE) of the simulated values was lower than 20%.The results indicated that SWUF could be used to simulate the daily soil water dynamics in P. tabulaeformis plantation and the secondary forest. However, modification is needed to model soil water of 0-40 cm layers in R. pseudoacacia plantation due to rapid depletion in the soil water.