The influences of spatiotemporal change of cultivated land on food crop production potential in China

The impact of changes in cultivated land on the production potential of food crops in China during the period of 1990–2010 was studied using land use data and the Global Agro-ecological Zones (GAEZ) model. The contribution of crop production potential per unit cultivated land area (PPCLA) to the total food-energy based production potential (TPP) of food crops was further investigated. From 1990 to 2010, China has experienced a net increase of cultivated land, resulting from a net increase in northern China and a smaller net decrease in the south. However, the TPP reduced by 9.64 × 1012 kcal despite an overall cultivated land increase for crops. This was attributed to the spatial heterogeneity of PPCLA in the cultivated land, whereby the average PPCLA of the newly cultivated land was much lower than that of the lost land. The PPCLA gap between the newly developed land and the lost cultivated land expanded from 3.16 × 106 kcal/ha in the first decade (1990–2000) to 6.49 × 106 kcal/ha in 2000–2010. Contributions of PPCLA to TPP varied among regions, and the regions with the largest contributions were consistent with those with the largest PPCLA gaps. Such regions included the Sichuan Basin and surrounding region in 1990–2000, and the Huang-Huai-Hai Plain during 2000–2010. Based on these research findings, key implications for land use policies in relation to major food crops in China are discussed.