高台县耕地地力评价

EVALUATION OF CULTIVATED LAND FORCE IN GAOTAI COUNTY

关键词:  耕地地力评价改良高台

Key words:  arable land  soil fertility  evaluation  improved  Gaotai

摘要:

［目的］根据高台县耕地地力评价结果和不同地力等级统计结果，分析耕地质量存在的问题，并为高台县耕地地力保护和耕地质量提升提出建议对策。［方法］把甘肃省张掖市高台县土壤图、土地利用现状和行政区划图叠加求交，得到3309 3万个评价单元。利用特尔斐法选取耕层盐化、质地构型、有机质、质地、有效磷、耕层厚度、海拔、CEC(土壤阳离子交换量，下同)、速效钾和坡度作为高台县耕地地力评价指标体系并建立层次分析模型和隶属函数模型，由专家打分取平均值给出各层次权重和评价指标的隶属度。再使用GIS软件根据公式计算耕地地力综合指数IFI值。［结果］IFI值＞0850 5的划为一等地，IFI值在0850 5～0720 0的划为二等地，IFI值在0720 0～0662 6的划为三等地，IFI值在0662 6～0630 0的划为四等地，IFI值＜0630 0的划为五等地。［结论］当前耕地存在的主要问题是因化肥过量使用造成的面源污染和灌溉造成的盐渍化，建议从改良耕作制度、轮作休耕、化肥减量增效、增施有机肥、节水灌溉技术和秸秆还田等措施加以改良。

Abstract:

According to the evaluation of the cultivated land productivity in Gaotai county and the statistical results of different levels of the cultivated land, the main problems and main obstacles in the current cultivated land quality were analyzed. And then, this paper puts forward some suggestions and countermeasures for the protection of cultivated land and the improvement of cultivated land quality in Gaotai county. Based on the soil type map, land use status and administrative zoning map superposition intersection, it received 33 093 valid evaluation unit and gave each unit the evaluation index to carry on the corresponding assignments. Delphi method was used to select top layer saline, texture configuration, organic matter, texture, effective phosphorus, top layer thickness, elevation, CEC, phosphorus and potassium and slope 10 indexes as farmland productivity evaluation index system, the hierarchical analysis model and subordinate function model was set up by the expert scoring average level weights. Then the GIS software was used to calculate the IFI value of the cultivated land comprehensive index according to the calculation formula of the cultivated land comprehensive index IFI value, i.e., IFI value > 0.8505 as a first-class, IFI values between 0.8505 ~ 0.7200 is divided into second class, IFI values between 0.7200 ~ 0.6626 is divided into three classes, IFI values between 0.6626 ~ 0.6300 is divided into four grades, IFI values < 0.6300 between is divided into five, etc. The current main problems of cultivated land were non-point source pollution caused by excessive fertilizer use and irrigation cause of salinization, the main obstacle factors included low content of soil organic matter, soil thin, high soil salinity, soil harden and so on. It put forward some suggestions to ensure the sustainable utilization of cultivated land resource from improving fallow cropping system, crop rotation, and tillage, reducing fertilizer efficiency, increasing organic fertilizer application, and other new type fertilizer and water-saving irrigation techniques.