Spatiotemporal differences and influencing factors of multiple cropping index in China during 1998-2012

Raising the level of the multiple cropping index (MCI) plays a critical role in food production of China. Therefore, exploring the spatiotemporal differences and factors of the MCI in China is of important practical significance. This paper examines the trend of multiple cropping index (MCI) changes in China at the national, regional and provincial levels during 1998-2012. Based on the Theil index, this paper explores the spatiotemporal differences of the MCI in China. Additionally, a spatial econometric model is used to identify the determinants of the spatiotemporal differences of the MCI from a behavioral perspective. The results are summarized as follows: (1) From the national perspective, the MCI shows an increasing trend year by year, rising from 120.1% in 1998 to 134.26% in 2012; (2) at the regional level, the northeastern region is the fastest growing area in terms of MCI, whereas the central region is the slowest growing area. The central region has the highest MCI level, whereas the northeastern region is connected to the lowest MCI level; (3) according to the Theil index value, the differences in the MCI show a narrowing trend from 0.11 in 1998 to 0.03 in 2012, which is primarily attributed to the differences among the four regions; (4) the MCI shows differences among China's 31 provinces, and the gap that it shows is great; and (5) the proportion of non-agricultural population has a significant negative effect on the MCI. However, the proportions of non-agricultural industry, agricultural policy, per capita operating arable land area and rural household per capita net income have a significant positive impact on the MCI. Therefore, the following policies are suggested to increase the level of China's cultivated land MCI: transferring rural surplus labor, increasing the farmers' income, accelerating the transfer of the use rights of arable land, developing the scale effect of land use, providing further support and benefits to farmers in less developed regions and major grain-producing areas, and strengthening the role of the national agricultural policy.