通过综合80年代初以来的农作物面积与产量统计、耕地分布、农业灌溉分布以及作物生长适宜性分布等多源数据,利用基于交叉信息熵原理的作物空间分配模型(Spatial Production Allocation Model,SPAM),获得了我国10km像元尺度的水稻分布信息。在此基础上,重点分析了80年代初以来水稻种植面积与产量的时空变化特征。总体来看,在全国水稻种植区域内发生变化的地区中有超过50%的地区水稻种植面积出现缩减态势,但仍有近70%的地区水稻产量在增加。空间变化来看,种植面积缩减主要发生在东南沿海的广东、福建和浙江等省,而增加主要出现在东北地区的吉林和黑龙江等省,我国水稻种植重心因此向东北方向迁移约230km,产量重心向东北迁移约320km。同时,研究还发现我国水稻种植面积变化对产量增减具有重要影响,其中产量增加表现为面积与非面积因素的共同作用,数据显示种植面积扩展对水稻增产的平均贡献率约54.5%,而在产量减少的区域,面积缩减对减产的贡献率高达80%以上。
Rice is one of the most important staples in China. Rice's spatial-temporal distributions, which are vital to agricultural, environmental and food security research, are affected by natural conditions as well as social-economic developments. In recent years, most of agricultural land use change studies are focused on cultivated land change and its impact, while few are focused on arable crop area change because crop sown area estimates are based on statistics by administrative units, and such data lack accurate information on spatial and temporal variations. Other estimates are based on remote sensing, such data limited by spatial resolution which is difficult to capture the finer information of crops. Thus, multi-source data integration has become an effective way to determine spatial distributions of crops. Spatial Production Allocation Model (SPAM) is a multi-source data integration model that integrated arable land distribution, administrative unit statistics of crop data, agricultural irrigation data,and crop suitable data. It applied a cross-entropy method to allocate the statistics data of crop area and production down to such a fine spatial location, such as a pixel. This research uses the SPAM-China model to get a series of spatial distributions of rice area and production with a 10-km pixel at national scale, based on long-term county- and province-level agricultural statistics since the early 1980s, and then, analyzes the pattern of spatial and temporal changes. The results show that there are significant changes in rice in China during 1980-2010. Overall, more than 50% of rice area decreased, while nearly 70% of rice production increased in the change region during 1980-2010. Spatially, most of the increased area and production were in Northeast China, especially, in Jilin and Heilongjiang, most of the decreased area and production were located in southeastern China, especially, in rapidly urbanized provinces of Guangdong, Fujian and Zhejiang. Thus, the centroid of rice area was moved to northea