AnnAGNPS模型数据库的建立——以黄土丘陵沟壑区砖窑沟流域为例

Database Construction for AnnAGNPS Model--Case Study of Zhuanyaogou Watershed in Hilly-gully Loess Plateau

年农业非点源污染模型(AnnAGNPS)是一个由美国农业部农业研究局和自然资源保护局联合开发的连续模拟来自流域的地表径流、沉积物、污染负荷的分布式参数模型,以位于黄土丘陵沟壑区的晋西北河曲县砖窑沟流域为例,建立了AnnAGNPS模型数据库,包括气候、地形、土壤、土地利用等相关参数的确定过程,充分使用了GIS、RS、农田调查等技术和方法,重点分析了降雨特征、模拟单元的划分、土壤相关参数的转换、农田操作措施、地表粗糙度、施肥、径流曲线值等因子,为该模型在中国的合理使用奠定了基础。

This paper describes the database construction for the Annualized Agricultural Non-Point Source model, AnnAGNPS, using the Zhuanyaogou Watershed in Hilly-gully Loess Plateau as a case. AnnAGNPS is a tool for comparing the effects of implementing various conservation alternatives within the watershed. Cropping systems, fertilizer application rates, water and dissolved nutrients from point sources, sediment with attached chemicals from gullies, soluble nutrient contributions from feedlots, and the effect of terraced fields can be modeled. Version 1 of AnnAGNPS was released in February 1998. In this paper, AnnAGNPS model database are constructed including weather, topography, soil and land use in Zhuanyaogou watershed （29.16 km^2） on the Loess Plateau, China. The average annual rainfall erosivity is 1 439.8 MJ·mm·hm^-2·h^-1·a^-1, and the seasonal distribution is very centralized. The percentage of the sum of continual six semi-month rainfall erosivity to annual rainfall erosivity is 79.3%. Based on Digital Elevation Models （DEMs） and TopAGNPS module, a CSA of 1 ha and a MSCL of 50 m werc chosen to represent the existing stream network for the watershed, and 2021 cells and 864 reaches were defined to delineate the watershed. According to the available soil particle-size data assuming a lognormal distribution, Kachinsky classification system of soil texture, was interpolated or extrapolated into the USDA triangle one. Land use maps were interpreted from aerial photos and the field survey The field rotation sequence, typical cropland field operations, fertilizing type, and random roughness were, analyzed. The average runoff curve numbers of land use types were identified. The study has laid foundation for application of AnnAGNPS model in China.