基于土壤水分分布的土地利用空间优化方法——以黄土高原杏子河流域为例

选择具有黄土丘陵沟壑区典型特征的杏子河流域为研究区域,在分析流域土地利用现状的基础上,基于GIS的栅格模型将累积土壤水分补给量模型、土壤侵蚀模型和多目标非线性优化模型结合起来,建立了黄土丘陵沟壑区土地利用空间优化模型,并应用此模型探讨了杏子河流域在综合治理过程中的一些特点和规律。研究表明,经济效益随着治理程度的增加而持续增加,生态效益在治理程度达到30%后明显减小。由于综合考虑了土壤水分的空间分布,优化后的经济效益明显增加,生态效益差别不大,但是退耕还林的效果更好。

Spatial Optimization of Land Use Based on Soil Water Distribution in the Hill-gully Areas of the Loess Plateau - A Case Study of the Xingzihe Watershed

Based on the cumulate soil water replenishment model,soil erosion mode l,and multiple objective nonlinear optimum models,an allocation model for spatia l optimization of land resource was established.The method includes four steps.T he first step,with the objective of making spatial distribution of water resourc e suitable for crop growth in the study area,is to establish the water distribut ion models based on grid data model,SCS discharge model and the principle of wat er content equilibrium.The second step is to establish a soil water prediction model to analyze watershed soil and water loss situation.In this step,Digital El evation Model(DEM),land use map,soil type distribution map,climate,meteorologica l and hydraulic data are required.The third step is to integrate the water conte nt distribution model,soil and water loss model,and a multiple objective model f or land use optimization in order to get the quantitive structure of land use.Th e last step is to allocate the optimized land use structure spatially based upon the current land use patterns and the principles of ecology.To test the model,a typical watershed,Xingzihe watershed,on the Loess Plateau in northern Shaanxi p rovince was selected as the study area.As a result,land resources at the watersh ed were allocated based on the local integrated regulation programming.The ecolo gical and economic benefits of the optimum land use structures were discussed.It is indicated that the eco,environment of the study area would be apparently imp roved after watershed regulation.Moreover,the local farmers' income would be gre atly increased,and the major source of agricultural income would be shifted to w oods and fruits.At the same time,the case study also revealed that both of the e conomic benefit and the ecological benefit will increase until the management de gree reaches 30%.When the degree exceeds 30%, the economic benefit will continue to increase but the ecological benefit will remain almost unchanged.The propose d method can produce better result for local land use structural regulation.