| In order to evaluate the distribution characteristics of the arable lands in Northwest China and its status in the whole country, based on the accomplishments of cultivated land classification at the national level for the five provinces in Northwest China, the quantitative and grade and spatial distribution characteristics of the arable lands were analyzed in Northwest China, as well as the influential factors on land qualities. The results showed that medium and low grade lands were broadly distributed, up to 93.04% of the area. The average arable grade was 11.9, 2.1 lower than the national average level (9.8). The distribution of arable land natural quality and utilization grade were roughly the same in Northwest China. High-grade arable lands were mainly in Shaanxi, medium-grade arable lands were mainly in Xinjiang, and low-grade arable lands were mainly in Gansu and Shaanxi. Arable land area in Qinghai and Ningxia were small, majority of which was medium or low-grade. In addition, the distributions of arable land economic grade were slightly different. High-grade arable lands were mainly in Xinjiang, medium-grade arable lands were mainly in Xinjiang and Shaanxi, and low-grade arable lands were mainly in Gansu and Shaanxi. Qinghai had large area of low-grade arable lands, and Ningxia had large area of lower-grade lands. The arable land quality of Northwest China was mainly influenced by geomorphological structure, soil conditions and basic farmland constructions. Factors that influenced the variations in spatial distributions in different provinces were mainly determined by different dominant factors of the provinces, which further controlled the spatial distribution characteristics of the arable land quality in Northwest China. |