基于GIS的县域耕地资源数据库建立及耕地地力评价

用现代耕地资源管理理论和方法，结合GIS技术，在第二次土壤普查资料基础上，通过实地调查对大量数据进行补充，用GIS软件建立了定安县1:50000耕地资源数据库。并在此基础上选取排涝能力、轮作制度、成土母质、土壤侵蚀类型、pH、有机质、全氮、有效磷、速效钾、交换性镁、耕层厚度、障碍层状况12个要素作为评价指标。叠加土壤图、基本农田保护块图或土地利用现状图，得到2411个评价单元。根据模糊数学理论，采用特尔菲法、层次分析法和加法模型计算出耕地地力综合指数，运用等距分级法形成耕地地力等级。在此次以水稻土为主的定安县耕地调查中，查出耕地总面积66729.47hm2，按综合指数分级方案划分的地力等级结果表明，二级地2241.60hm2、三级地27261.27hm2、四级地26065.93hm2、五级地11160.67hm2，分别占定安县耕地总面积的3.36%、40.85%、39.06%、16.73%，没有一级、六级、七级和八级耕地，面积较大的耕地属于三级和四级地，将其归入全国耕地地力体系后，定安耕地整体在全国处于中等级水平。

Establishment of GIS-based County Land Resources Database and Its Application on evaluate arable land productivity

Ding'an county's arable land resources database in 1:50000 scale was established with the modern management theory and method of arable land resource and GIS technology,based on the second general survey soil and mass data from field investigation in the paper.With these databases,12 essential evaluation factors was decided,such as drainage capability,crop rotation system,parent material,soil erosion type,soil acidity,organic matter,total nitrogen,available phosphorus,available potassium,exchangeable magnesium,plow layer depth,obstacle layer type.Also 2411 evaluation units was obtained by laying over soil map and fundamental farmland protection plot map or current landuse map.The grade of arable land productivity was formed according to the theory of Fuzzy Mathematics,adopting Telphi Principle,Analytic Hierarchy Program and Addition Model,and applying the principle of equidistant grading to form.According to the field survey of arable land in Ding'an county,it is found that the total arable land area was 66729.47hm2.With the aggregate index,the arable land was graded as follows:the grade two land area was 2241.60hm2,the grade three was 27261.27hm2,the grade four was 26065.93hm2 and the grade five was 11160.67hm2,sharing each percentage as 3.36%,40.85%,39.06% and 16.73% respectively.The grade one,grade six,grade seven and grade eight arable land was not found this time.In total,the grade three and grade four arable land occupied the most portion and the arable land productivity was medium level in term of the production class system of nation-wide arable land in China.