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1995~2000年间淮河上游山丘区实施了国家退耕还林(草)工程和水土保持重点县工程。基于研究区1995年和2000年两期土壤侵蚀强度分级数据,利用地理信息系统(G IS)技术,采用网格和插值法,分析研究区单位面积土壤侵蚀量变化以及土壤保持功能经济价值的变化。结果表明:(1)淮河上游山丘区总面积约2.6×104km2,其中农田、森林和草地3种生态系统类型仍然是研究区土壤侵蚀量的主要贡献者。(2)研究区5年间土壤侵蚀总量下降了152.85万t。(3)土壤侵蚀模数高值主要分布于研究区的东南部,这种分布趋势与地形因子和气候的关系极为密切。(4)1995~2000年淮河上游山丘区土壤保持功能经济价值呈现增加的区域的面积和价值增幅均大于呈现减少的区域的面积和价值减幅。(5)研究区土壤保持功能总经济价值净增加1 001.86万元,绝大部分市县的土壤保持功能经济价值都发生了不同程度的增加。
From 1995 to 2000, the national project of returning farmland to forest (grassland) and key counties for soil and water conservation implemented the project in the upper reaches of the Huaihe River. Based on the grading data of soil erosion intensity in 1995 and 2000 in the study area, using GIS (Geographic Information System) technology and grid and interpolation method, the change of soil erosion per unit area and the change of economic value of soil conservation function were analyzed . The results show that: (1) The total area of the upper reaches of the Huaihe River is about 2.6 × 104 km2, and the three types of ecosystem of farmland, forest and grassland are still the major contributors to the soil erosion in the study area. (2) The total amount of soil erosion in the study area decreased by 1.5285 million tons in five years. (3) The high values of soil erosion modulus are mainly distributed in the southeast of the study area. The distribution trend is closely related to the topography factors and climate. (4) From 1995 to 2000, the area and value increase of the increasing economic value of soil conservation function in the upper reaches of the Huaihe River was greater than that of the decreasing area. (5) The total net economic value of soil conservation function in the study area increased by 10.8186 million yuan, and the economic value of soil conservation function in most cities and counties had increased in varying degrees.