Physical suitability evaluation of reserve resources of cultivated land in China based on SOTER

Physical suitability evaluation of reserve resources of cultivated land provides a scientific basis for reasonable exploitation and utilization of these lands aiming to ensure food supplies of China. Taking the whole reserve resources of cultivated land in China as the evaluation object based on 1:1000000 scale SOTER of China, nine factors of climate, landform and soil were adopted, fuzzy analysis combined with the Delphi method were used to quantify the membership functions of the selected factors and the weight contributions of individual factors were determined using the Delphi method and an analytic hierarchy process (AHP). Physical suitability indices of each evaluation unit were calculated by using the combination method of critical conditions with integrated index model, and then the suitability grades were classified. Evaluation results showed that about 56.6 × 104 km2 reserve resources of cultivated land had suitable physical quality, among which grade 1, 2, 3, 4, 5 accounted for 15.9%, 19.5%, 25.8%, 19.1% and 19.7%, respectively. Heilongjiang, Jilin, Liaoning, Shanxi. Hebei, Guizhou, Guangxi, Shandong and Jiangxi provinces could be the main areas for exploitation of reserve resources of cultivated land. With the decrease of suitability grade of reserve resources of cultivated land, the most serious limited factor changed from soil condition to climate and landform conditions. Fuzzy functions and the combination of critical conditions with integrated index model can improve effectively the rationality of evaluation result.