基于能值理论的中国耕地利用集约度时空变化分析

为揭示1990－2011年中国耕地利用集约度的时空变化特征，采用能值理论的研究方法，将耕地利用集约度分解为生产要素集约度和复种指数2个指标的乘积，剖析了中国农业机械、化肥、农药、农膜、劳动力等五大生产要素集约度和复种指数的时空变化规律。结果表明：1990－2011年，包括农业机械、化肥、农药和农膜 4种生产要素的工业辅助能集约度呈线性增长趋势，而劳动集约度则呈现显著的线性下降趋势，1996年工业辅助能集约度在生产要素集约度中所占比例首次超过50%，表明20世纪90年代中期中国开始进入现代农业发展阶段；期间复种指数增长率为0.1794，其对于耕地利用集约度的提高起到了关键性作用；1996年劳动集约度高的主要是处于传统农业生产阶段中的西部农业省份，而工业辅助能集约度高的大都是初步或基本进入现代农业发展阶段的经济发展水平高或工业基础好的省份；1996－2008年，沿海经济发达区、西部地区和部分粮食主产区劳动集约度下降幅度较大而工业辅助能集约度上升幅度大；1996－2008年，复种指数下降是导致南方水稻主产区耕地利用集约度下降的主要原因，而绝大多数北方地区耕地利用集约度增长也主要是由于复种指数的增长。

Temporal and spatial change of cultivated land use intensity in China based on emergy theory

Limited cultivated land has become one of the major restrictions for China's social and economic development, and how to use it intensively is the focus of the Chinese government and research scholars. Based on emergy theory and methods, the cultivated land use intensity (I) was composed of production factors intensity (P) and multiples the multiple cropping index (M). On this basis, the paper analyzed the temporal and spatial change law of all the five production factor intensities, which are farm machinery, fertilizer, pesticide, agricultural film and labor, and the multiple cropping index in China from 1990 to 2011. The results showed: Firstly, during the past 22 years, the farm machinery intensity, fertilizer intensity, pesticide intensity, and agricultural film intensity were all in a linear growth trend, and their annual growth rates were 6.59%, 2.89%, 3.88% and 7.42% respectively; while the labor intensity was in a linear decreasing trend, and its decreasing rate was 5.10 percent. In 1996, the possession of industrial supplementary energy intensity, including farm machinery, fertilizer, pesticide, and agricultural film, in the total production factors intensity first exceeded 50 percent, which meant that China had entered the modern agriculture stage in the middle of 1990s. During the study period, multiple cropping index was also in a linear growth, and the annual growth rate is 0.79%; its total increasing rate was 0.1794 in the past 22 years, and was the major driving force of the increase of land use intensity. Secondly, in 1996, the provinces with high labor intensity and low development of modern agriculture were mainly located in the western part of China, and the typical characteristics of these provinces were that they were all rated with a relatively low level of social and economic development; While in the provinces with high development of economic levels and a good industrial foundation, the labor intensity was low and development of modern agriculture was high. From 1996 to 2008, most provinces in the western part of China and some of the coastal provinces in the eastern part of China, labor intensity decreased a lot; while in the provinces with high economic development and the provinces with more land and fewer persons, labor intensity decreased only a little. In the provinces with high economic development in the eastern coastal part of China and some major grain producing areas, industrial supplementary energy intensity increased a lot; In the provinces with high development of modern agriculture, industrial supplementary energy intensity increased only a little. Thirdly, from 1996 to 2008, in the major rice producing areas in southern part of China, the multiple cropping index decreased a lot, which was the major reason that contributed to the decreasing of their land use intensity; In most provinces in the northern part of China, the multiple cropping index increased a lot, which was the major reason that improved their land use intensity.