2000～2015年中国地级市化肥使用量的时空变化特征

Spatial and Temporal Variations in Fertilizer Use Across Prefecture-level Cities in China from 2000 to 2015

化肥在农业生产中对粮食增产起到至关重要作用,但过量使用也带来诸如地表水富营养化、土壤结构恶化及农业承载力下降等一系列环境问题.目前对于化肥的研究多集中于利用效率方面,而空间变化特征的研究很少,充分认识化肥使用量空间上的变化对我国农业的可持续发展同样具有重要意义.基于2000~2015年全国地级市化肥折纯使用量和播种面积、粮食产量等数据,采用空间自相关分析、冷热点分析、核密度分析和标准差椭圆分析等方法,比较了2000、2005、2010和2015年这4年全国尺度各地区化肥使用总量及单位面积化肥使用负荷的时空变化特征.结果表明:①2000~2015年我国的化肥折纯使用量呈直线增加趋势,而在区域内一直处于比较高的集聚状态.化肥折纯使用量经历2000~2005年区域聚集状态增强,2005~2010年聚集状态减弱,2010~2015年又增加的过程.②从全国化肥使用的空间分布来看,2000~2015化肥使用总量呈现增加趋势,主要表现在化肥使用量超标的地级市变多,区域变广.东部经济发展较快的地区,如广东省和福建省由于播种面积减少比例大于化肥使用量的增长比例,导致超标地级市较为密集.③2000~2015年我国粮食重心的移动轨迹和化肥使用量的移动轨迹不相符,粮食重心往东北地区移动,而化肥使用量的重心往西部移动.一是表明东北地区的商品粮地位越来越重要,二是表明我国西部地区化肥使用量逐渐增加,有超标的趋势,应加以重视.

Chemical fertilizer plays an important role in increasing grain production in agricultural systems but overuse also brings a series of environmental problems,such as eutrophication of surface water,deterioration of soil structure,and the decline of agricultural carrying capacity.At present,research on chemical fertilizer use mainly focuses on utilization efficiency while studies on the spatial characteristics of its use are limited.It is also of great significance for the sustainable development of agriculture in China to fully understand the spatial changes in the use of chemical fertilizers.Based on data of pure chemical fertilizer use,sown area,and grain yield in prefecture-level cities from 2000 to 2015,spatial autocorrelation analysis,cold and hot spot analysis,nuclear density analysis,and standard deviation ellipse analysis were applied.The temporal and spatial variations in total fertilizer use and fertilizer load per unit area in 2000,2005,2010,and 2015 were compared.The results showed that:①The use of chemical fertilizer in China increased linearly from 2000 to 2015 but it has been in a relatively high agglomeration state in the region.The pure use of chemical fertilizer experienced a process of increasing regional aggregation from 2000 to 2005,weakening from 2005 to 2010,and increasing from 2010 to2015.②From a spatial perspective,the total amount of chemical fertilizer applied between 2000 and 2015 showed an increasing trend,shown by an increase in the number of prefecture-level cities and regions in which the use of chemical fertilizer exceeded the standard.The eastern regions of China,which have experienced rapid economic development,such as Guangdong Province and Fujian Province,are over the critical load of chemical fertilizer more and denser than other prefecture-level cities because the proportional reduction in sown area is greater than the increase in chemical fertilizer use.③The movement track of the grain production center in China from 2000 to 2015 was not consistent with the movement track of chemical fertilizer usage.Specifically,the center of grain production moves to the northeast,while the center of chemical fertilizer use moves to the west.This demonstrates that the status of commercial grain production in Northeast China is becoming more and more important,and that the use of chemical fertilizer in the western regions of China is gradually increasing.Here,there is a trend for exceeding the standard,which required further attention.