黑河下游额济纳绿洲土地生产潜力的动态变化及影响因素分析

The Land Potential Productivity in Ejina Oasis in the Lower Reaches of the Heihe River: Dynamic Change and Driving Factors

在通过Visual MODFLOW软件模拟地下水位的基础上,采用GIS技术进行栅格运算,把影响土地生产潜力的各个因子作为"修正"系数,运用逆向因子修正法分析黑河下游土地生产潜力的变化.在计算不同影响因素组合条件下土地生产潜力的同时,结合不同的分水方案,对各影响因素进行分析.结果表明:在狼心山来水量为7.5×108 m3.a-1时,区域的水分有效系数整体增加,植被覆盖度增大,土地生产潜力大幅度提高,能有效改善当地的生态环境.与现状相比,在来水量为2.5×108 m3.a-1时,东河下游的水分有效系数出现降低的情形;在来水量为5.0×108 m3.a-1和7.5×108 m3.a-1时,其水分有效系数均显著增加.通过对影响因素的剖析有利于预警当地荒漠化发展的趋势,进一步建立土地沙漠化的判别指标体系,从而为黑河流域的土地生产服务.

Land potential productivity change in the lower reaches of the Heihe River was analyzed by using the method of limiting factor conversed modification,which took various factors affecting the land potential productivity as correction coefficients,with the support of Visual MODFLOW used for modeling groundwater level and GIS platform used for grid calculation.In the research,driving factors were analyzed in the processes of calculating land potential productivity under different water-diversion schemes.Analytical results show that when water input in Langxinshan is 7.5×108 m^3·a^-1the effective coefficient of water,vegetation coverage and land potential productivity will increase,and the ecological environment will improve.Compared with the status quo,the effective coefficient of water will decrease when water input is 2.5×108 m^3·a^-1in the lower reaches of the Donghe River,However,the effective coefficient will increase significantly when the water input is 5.0×108 m^3·a^-1or 7.5×108 m^3·a^-1The analysis of driving factors will be applied in early warning the local desertification trend,establishing evaluation index system,and providing theory basis for the land utilization of the Heihe River basin.