Cultivated land quality evaluation among hills and mountains of Chongqing City based on GIS

Natural quality grade index model of agricultural land classification, coupled with module-control method, was adopted to evaluate the cultivated land quality in 4 counties located in hills and mountains, in Chongqing, in order to acquire accurate evaluation results inter-districts. Firstly, with the aid of MapGIS, the multi-map superimposition method was used to define evaluation units and to extract unit attribute data. Secondly, comprehensive evaluation model of natural quality of agricultural land classification was built up which was comparable in 4 secondary districts in Chongqing. Thirdly, additional method of photo-thermal productivity index was ameliorated by adopting ratio of energy to standardize yield, and introducing harmonizing photo-thermal productivity coefficient. The results indicate that cultivated land quality gives priority to middling and high quality grade in Dazu located in hills region and Liangping located in low mountains and hills region, to middling and low quality grade in Pengshui located in low and medium mountains region, and to low and middling quality grade in Wuxi located in medium mountains region, which shows low or high hypsography gives significant effects on total quality of cultivated land in hills and mountains region. The evaluation method can acquire accurate evaluation results inter-districts and inter-farming systems.