广东省粮食供需时空格局

粮食供需差真实反映粮食供需的状况,对于保障粮食安全有着重要意义.研究以广东省为例,利用1994-2009年粮食生产及常住人口数据,构建空间集聚-扩散度和贡献指标,分析粮食供需差的空间分异,并采用格兰杰因果检验探析城市化与粮食供需差的因果关系.研究结果表明,1994-2009年,广东省的粮食供需差总体呈现上升的趋势和扩散的特征,粮食短缺从局部现象转变为普遍现象;21个地级市的粮食供需差趋于平稳、缓慢增长,且增长差异呈现变小的趋势.主导粮食需求和高贡献率地级市的空间分布特征分别是集聚→扩散→集聚与扩散;粮食供需差贡献存在显著的空间差异性,可以将所有的地级市划分为高增长指数、高贡献率,高增长指数、低贡献率,低增长指数、高贡献率,低增长指数、低贡献率4种不同的类型;而格兰杰因果检验表明,在城市化水平较低地区,城市化水平的提升将直接引起人均粮食供需差的变大.

Spatial-temporal Analysis of Grain Supply and Demand in Rapid Urbanization Regions in Eastern China: A Case Study of Guangdong Province

The balance of grain supply and demand accurately reflects the condition of grain supply and demand. It is of great significance to ensure grain security. Existing studies usually focus on single factor of grain supply and demand, however, the spatial-temporal changes of the relationship between grain supply and demand, especially how urbanization influences them are rarely involved. Basing on the statistic data concerning grain production and population of Guangdong Province from 1994 to 2009, and taking Guangdong Province as the research object, the space differentiation is analyzed through constructing space cluster-diffusion and contribution index and the relationship between urbanization level and the balance of grain supply and demand is analyzed with Granger causality test. Since 1994, the balance of grain supply and demand of Guangdong Province appears rise and diffusion and grain shortages change to common phenomenon. The balance of grain supply and demand of the 21 cities tends to slow down growth and the difference among them appears smaller. The spatial distribution characteristic of cities leading grain needs is cluster→diffusion→cluster, and for cities with high contribution rate is diffusion. The balance of grain supply and demand has significant spatial differences. All the 21 cities can be divided into four types as high growth index with high contribution rate, high growth index with low contribution rate, low growth index with high contribution rate and low growth index with low contribution rate. Granger causality test indicates the improvement of urbanization level can enlarge the per capita share of the balance of grain supply and demand in low urbanization regions.