Integrated indicators-based gradation of cultivated land quality in mountainous region of Southwestern China

The gradation of cultivated land is to assess the suitability of cultivated land for agricultural production in terms of natural and economic properties of land. It can be used to evaluate sustainability of land use and soil management practices. Formal and informal surveys, Delphi and comprehensive index method are adopted to identify appropriate integrated indicators, and measure the gradation of cultivated land quality. The determination of integrated indicators presents three basic features of cultivated land quality: stable plant productivity, social acceptability and maintenance of environmental quality. Pronounced concentration-dissipation law of total function score value occurs in paddy field units, with three ranges, i.e., 79∼68.5, 68.5∼59 and 59∼51. Total function score value in dryland units mainly ranges from 40 to 70, but slight concentration-dissipation law of each unit is still observed, with four ranges, i.e., 79∼68, 68∼51, 51∼37 and 37∼15. Paddy field quality is divided into three gradations, and the scales are 18 220.9 ha, 5410.6 ha and 2890.9 ha. Dryland quality is classified into four gradations, and the scales are 1548.6 ha, 8153.8 ha, 3316.3 ha and 685.2 ha. The total function score value of every gradation unit is conformed to the results of farmers’ assessment. Research results meet with the needs of accurate degree of the gradation of cultivated land quality. Integrated indicators-based gradation of cultivated land assessment accords with the characteristics of land resources and human preference in the mountains of southwestern China. This study will be useful to promote the monitoring of cultivated land quality, and to supply fine ground and knowledge for establishing appropriate cultivated land management practices in Southwestern China.