Abstract:

Quantity and spatial pattern of farmland has changed, which leads to significant change of farmland potential productivity under the influence of national ecological environmental protection project and the rapidly increased economic growth during the last two decades. In this study, farmland potential productivity in China was calculated based on meteorological data, terrain elevation data, soil data and land use data in 1990, 2000 and 2010 by using the Globe Agricultural Ecology Zone model (GAEZ). Then, the changes in farmland potential productivity in response to farmland change from 1990 to 2000 were subsequently analyzed. (1) In 2010, total farmland potential productivity is 1.055 billion tons in China, and the average farmland potential productivity is 7614 kg/hm², which shows tremendous heterogeneity in spatial pattern. The productivity in eastern China is high, while that of northwestern China is low. High value region of farmland potential productivity is mainly distributed in South China and the middle and lower reaches of the Yangtze River. (2) The obvious tempo-spatial heterogeneity of farmland change from 1990 to 2010 has a significant influence on the farmland potential productivity in China. The trend shows the farmland potential productivity decreased in southern China and increased in northern China. Furthermore, the gravity of the growth of farmland potential productivity moves gradually from northeastern to northwestern China. The net decrease of farmland potential productivity is 2.97 billion tons, which occupies 0.29% of the national total productivity. (3) There is a huge difference of the farmland potential productivity in response to farmland change between two periods from 1990 to 2000 and from 2000 to 2010. During the first decade, net increase in the cultivated land areas is 10.11 billion tons, which primarily spread across Northeast China Plain and arid and semiarid regions of North China. During the next decade, net decrease in the cultivated land areas is 13.08 billion tons, primarily distributed in the middle and lower Yangtze River region and the Huang-Huai-Hai Plain. In general, during the last two decades, the reason for the increase of the farmland potential productivity may contribute to the reclamation of grassland, woodland and unused land, and the reason for the decrease of the farmland potential productivity may result from the urbanization that occupies the cultivated land and Green for Grain Project that returns farmland to forests and grasslands.

Key words: farmland, production potential, GAEZ model, China