Spatial distribution characteristics of arable land grade in Western China

Understanding the distribution characteristics of arable land grade in the Western China is significant to make the scientific decision base for the use and improvement in arable land quality. In this study, the distribution characteristics of the arable land grade in the Western China including 12 provinces were analyzed based on the accomplishments of cultivated land classification in China. The results showed that the average arable grade was 11.2 and ranged from 4 to 15, compared with the national level, which was relatively lower. There was a great gap for arable land grade among the different provinces. The arable land grade in the southern provinces such as Guangxi, Sichuan, Chongqing, etc, had a higher quality, which ranged from 6 to 10, however, that in northern provinces such as Gansu, Neimeng, Qinghai etc, had a lower grade and that ranged from 10 to 15. According to the land utilization zone in China, arable land grade in southwest zone was higher than that in northwest zone and Qinghai-Tibet zone. The arable land grade was significant different with the different agricultural grading zones. Arable land grade was higher in such agricultural grading zones as south China, the southern Yangzi river, and Sichuan basin than that in Tibet plateau, Inter- Mongolia region, and the northeast of China. Arable land grades were increased with the increasing in cropping indicator, and the available degree of irrigation. The arable land grade was higher in low altitude than that in high altitude within the same agricultural grading zone. The results indicated that the arable land use and policy making for improvement in arable land quality should be formulated in accord with the distribution characteristics of the arable land. This research provides a reference for policy making about space arrangement optimization and quality improvement for arable land in Western China.