1990～2015年长江流域县域粮食生产与粮食安全时空格局演变及影响因素分析

长江流域粮食生产与经济发展在全国均占据重要地位，研究近25年长江流域粮食生产与粮食安全时空格局演变及影响因素，可为我国粮食安全及流域可持续发展提供科学依据。基于1990、1995、2000、2005、2010和2015年长江流域县域粮食产量、户籍人口数据、农业化肥使用量和粮食播种面积（740个区县），运用粮食变化指数、探索性空间数据分析（ESDA）、重心转移模型和空间误差模型(SEM)研究其时空格局演变特征及影响因素。研究结果表明：（1）1990～2015年长江流域粮食产量总体呈增长趋势，东西差异显著，年均增长率为0.5%，上中下游依次为0.6%、0.8%和 -0.7%；上游为劣势区，中游为优势增长区，下游为减弱区。（2）粮食产量冷点聚类一直分布在上游地区，聚类格局在2000年左右由西南边界的“L”型转变为西北倒“L”型；下游江淮地区与太湖平原的热点集聚在2000年后消失，且长期处于减产状态；人均粮食占有量与粮食产量时空格局演变呈较高的空间相似性，2000年为流域粮食生产与粮食安全格局发生变化的转折点。（3）1990～2015年长江流域一般余粮县和重要余粮县重心呈现出“南下西移”态势，缺粮县和供需紧平衡县重心发生了“从南向北、从西向东”迁移变化。（4）粮食播种面积和农业化肥施用量对粮食生产均具显著性正向效益。

Spatial-temporal Pattern and Influencing Factors of Grain Production and Food Security at County Level in the Yangtze River Basin from 1990 to 2015

Grain production in the Yangtze River Basin plays an important role in China. Rapid growth in population and economic development in the Yangtze River Basin over the past 30 years has occurred at the cost of encroaching croplands, resulting into the changes in grain production and food security. This paper presented a study on spatial-temporal pattern and influencing factors of grain production and food security at county level in the Yangtze River Basin in the recent 25 years, based on the statistics of grain production, household registration population, agricultural fertilizer use and grain crops sown areas in 1990, 1995, 2000, 2005, 2010 and 2015. The spatial-temporal characteristics and influencing factors of grain production and food security were analyzed and identified by using grain change index, exploratory spatial data analysis (ESDA), gravity centers transfer model and spatial error model (SEM). The results showed: (1) Average annual changing rate of grain production was 0.5%, respectively for 0.6% of the upstream, 0.8% of the middle and -0.7% of the lower reaches. There was a significant spatial heterogeneity in grain production. The upstream area was inferior area and the middle area was dominant growth area, Lower reaches was the weakening area. (2) The cold point clustering of grain yield distributed in the upstream area. The year of 2000 was the turning point for the pattern change in grain production and food security. The cold points clustering pattern of grain production changed from “L” type in southwest boundary to inverted “L” type in northwest boundary after 2000 in the upstream of the basin. The hot spots clustering in the JiangHuai area and the TaiHu Lake Plain disappeared after 2000 and kept gong-term decline in production grain. The changes in spatial-temporal pattern of total grain production and per capital grain were similar. (3) The gravity centers of general surplus-grain counties and important surplus-grain counties were both expressed as moving to southern and western regions. And the gravity centers of grain shortage counties and tight balance of supply-demand counties were both expressed as moving to northern and eastern regions. (4) The sown areas of grain crops and agricultural fertilizer use all had significant positive effects on grain production.