基于MODIS数据的中国耕地高中低产田空间分布格局

A MODIS data derived spatial distribution of high-, mediumand low-yield cropland in China

人口的持续增长和食物消费水平的快速提升使得中国粮食自给问题越发受到关注。后备土地资源补给能力的不足和城市化过程对优质耕地的占用使得耕地资源"开源"和"节流"均存在一定困难,因此,提高耕地资源利用效率、提升耕地生产能力成为当前中国农业发展的根本策略,清晰地掌握全国高中低产田在空间上的分布区域成为国家中低产田改造与高标准农田建设规划的必要前提。本研究应用空间分辨率500 m的MODIS遥感数据和光能利用率模型,在空间上清晰地估算现实农田生产力的基础上,结合高分辨率的耕地分布数据和耕作制度区划信息,探索新的高中低产田划分方法,掌握中国高中低产田的空间分布格局。该方法既能够体现耕地资源条件的区域分异规律,也能表达耕地现实生产能力的空间差异性,并且有效克服了利用统计数据进行高中低产田划分时以县为统计单元导致的县内高中低产田格局不明确的问题。基于该方法划分的高中低产田分别占全国耕地面积的20.66%、39.56%以及39.78%。其中,低产田约有3/4分布于丘陵山地区;高产田则53%分布于平原区。高产田面积最大的五个省均位于黄淮海区域内,其面积总和占全国高产田面积的41.75%。耕地面积位列全国前三的黑龙江省、四川省和内蒙古自治区其高产田面积占比均不足15%。

With the population increase and food consumption upgrade in China, the issue of food self- sufficiency attracts much attention from both Chinese government and international society. Under the circumstances of inadequate cropland resources supply and plenty of cropland occupied by urban construction, improving the utilization efficiency of arable land resources and increasing the cropland productivity have become the fundamental strategies of agricultural development in China. Since 1988, cropland improvement projects（medium-yield and low-yield field improvement and high-standard cropland construction） have been launched and implemented on a large scale, therefore a spatially explicit map for the distribution of high-, medium- and low- yield cropland was essential for cropland improvement planning. In this study, a new method for recognizing high-, medium- and low- yield field is developed based on cropland productivity, which is calculated by using a light use efficiency model and MODIS data with a 500- m resolution. This method can not only reflect the regional heterogeneity of cropland condition, but also express the spatial differences on a grid scale. At the same time, it effectively overcomes the shortage of statistical data based method in a county unit. The results show that the proportion of high-yield, medium-yield and low-yield cropland in China is 20.66%, 39.56% and 39.78%, respectively. About 3/4 of low- yield cropland is located in the hilly and mountainous regions, while 53% of the high-yield cropland is located in plain area. The five provinces with the largest area of high- yield cropland are Henan,Shandong, Jiangsu, Hebei and Anhui, which are all located in the Huang-Huai-Hai region. The sum of the high-yield cropland area in these five provinces accounts for 41.75% of the national total high-yield cropland area. In Heilongjiang province, Sichuan province and Inner Mongolia autonomous region, where the cropland area ranks the top three of China, the proportion of high-yield cropland area in each province only accounts for not more than 15%.