基于GIS的市级耕地地力评价——以张掖市为例

EVALUATION OF CITY-LEVEL CULTIVATED LAND FERTILITIES BASED ON "GIS" TECHNOLOGY——TAKING ZHANGYE CITY AS AN EXAMPLE

关键词:  GIS 市级耕地地力评价 张掖市

Key words:  GIS  municipal evaluation of cultivated land fertilities  Zhang Ye City

摘要:

对于省市高级决策者而言，更加注重更大区域内的耕地质量分布情况，从而迅速、客观地做出符合区域内的决策部署。张掖市是甘肃省主要商品粮基地，全国蔬菜基地之一，全国杂交玉米种子生产基地，全国绿洲农业基地和旱作农业基地。辖一区五县，因耕地灌溉条件优越，属于典型的绿洲农业和生态农业区。全市境内各县区土壤类型差异小，耕地利用现状类型类同，土壤管理等相似，开展市级耕地地力评价比县级更有区分性、必要性和全局性。该文以张掖市12 232个耕地资源管理单元为评价单元，选取海拔、灌溉保证率、质地、pH、有效磷、有机质、质地构型和有效土层厚度作为评价指标，采用层次分析法和模糊数学方法建立层次分析模型和隶属函数模型，应用综合指数法通过GIS软件计算耕地综合自然要素的指数来表示和区分耕地地力，根据指数值的大小把张掖市耕地划分为一等地、二等地、三等地、四等地和五等地五个等级；并获取了10%管理单元上近3年主要粮食产量和其对应各单元的综合指数进行回归模拟，把张掖市耕地地力评价结果依次对应到国家等级体系中为五等地、六等地、七等地、八等地和九等地。

Abstract:

The distribution situation of arable land in large area is important for policymakers. However, it is difficult to evaluate the land fertility distribution. Zhangye city, as a main area of food production in Gansu province, is one of country vegetable produce base, hybridization corn seed produce base, nationwide oasis agricultural base and dry farming experiment base. There are five counties and one district in Zhangye, i.e., Linze, Shandan, Minle, Sunan and Gaotai county, Ganzhou district, and Shandan racecourse. Because of the advantage of irrigation, this area belongs to oasis agriculture and ecological agricultural area. Soil types, arable land use types, and the soil management are all similar in these counties. It is distinguished, necessary, and overall to conduct the evaluation of cultivated land fertility at city-level that that at county-level. Taking 12232 units of land resources management as evaluation units, this paper selected altitude, irrigation guaranteed rate, soil texture, pH, available phosphorus, organic matter, soil texture configuration and effective soil depth as evaluation indexes, applied AHP and Fuzzy Mathematics to establish the AHP model and the membership function model, used comprehensive index method based on GIS software to calculate the index of arable integrated natural elements to represent and distinguish farmland fertility, and divided the arable land into five levels according to the value of index, i.e., first level land, second level land, third level land, fourth level land and fifth level land. Simultaneously, it got the main yields of above 10% units in recent 3 years and its corresponding index of each unit regression simulation. According to the relationship between grain yield and soil fertility levels, the results of farmland evaluation of Zhangye City were fifth level land, sixth level land, seventh level land, eighth land and ninth level land corresponding to the national land hierarchy system.