The impact of cultivated land spatial shift on food crop production in China, 1990–2010

Abstract

Abstract Cultivated land has been undergoing significant spatial shift during the last 2 decades in China, according to land‐use data derived from the Landsat Thematic Mapper. Based on soil organic matter data and yield data at county level, we developed a constant crop yield dataset at pixel level with a resolution of 1 km. Using this dataset, this paper quantitatively evaluates average crop yield change due to cultivated land spatial shift at national and regional levels. The results show that (a) at national level, the average crop yield per unit area decreased by 1.99% during the period 1990–2010. The main reason for this is that built‐up areas occupied a significant amount of high‐yield cultivated land whereas low‐yield land converted in ecologically vulnerable areas. (b) In spite of 77.2 thousand km 2 cultivated land was converted to built‐up areas, especially in areas with high economic value, such as Huang–Huai–Hai Plain, 329.4 thousand km 2 land was converted to cultivated land, especially in Northeastern and Northwestern China. (c) The quality gap between cultivated land converted to built‐up areas nationally and new cultivated land regionally suggests that the loss of 1 km 2 of cultivated land converted to built‐up area would, to achieve equivalency, need to be compensated by 1.54 km 2 of new land in Xinjiang, or more in Northeastern China. However, cultivated land expansion in these areas may cause land degradation and a series of ecological environment problems.