基于市域尺度的中国化肥施用与粮食产量的时空耦合关系

化肥施用是一把双刃剑,在促进粮食产量增加、保障粮食安全的同时,导致了生态环境退化,当前亟需辨明化肥施用与粮食生产之间的时空耦合关系,以便为维护粮食安全与生态安全提供有效的对策。以中国336个地级行政区为研究单元,分析2005-2015年中国粮食产量与化肥施用量的时空格局变化特征、化肥施用量与粮食产量的时空耦合关系及其动态变化过程。研究发现:(1)2005-2015年中国化肥施用量与粮食产量均呈上升趋势,化肥施用量的区内差异呈"粮食主产区-产销平衡区-粮食主销区"递减态势;而粮食产量的区域差异总体趋于增大,且呈"粮食主产区-产销平衡区-粮食主销区"递增态势。(2)化肥施用量增幅大致呈"东-中-西"阶梯式递增的趋势,而粮食产量增幅呈明显的南北分异特征。(3)从空间分布来看,胡焕庸线以东地区以"双高区"为主,胡焕庸线以西地区以"双低区"为主,且"低效施肥区"收缩,"他因素影响区"扩张。(4)期间,粮肥耦合关系以"双增型"为主,其他类型为辅,粮肥耦合关系主要向"双增型"与"他因素影响型"转变。

Spatial-temporal coupling relationship between chemical fertilizer application and grain yield in China at city scale

Fertilizer application is viewed as a double-edged sword, for it can increase grain production and ensures food security, at the same time, it can lead to degradation of eco-environment. At present, it is urgent to explore the spatial-temporal coupling relationship between fertilizer application and grain production, so as to provide effective measures and references to maintain food security and ecological safety. Selecting 336 administrative regions at the prefecture level as study units, the paper analyzes the changing features of China's grain production and fertilizer application in the spatial-temporal pattern, and the coupling relationship between fertilizer application and grain production as well as its dynamic process from 2005 to 2015. The findings are obtained as follows. (1) Both fertilizer application and grain production showed upward trends from 2005 to 2015, and regional differences in fertilizer application presents a decreasing trend from "main production areas, production-and-sales balancing areas to main sales areas". Meanwhile, the overall trend of grain production among different regions tends to increase from "main production areas, production-and-sales balancing areas to main sales areas". (2) Fertilizer application roughly presents a stepwise increase from "East-Centre-West", while grain production growth apparently shows north-south differential characteristics. (3) From the perspective of spatial distribution, the areas east of Aihui-Tengchong line were featured as "double-high areas" compared with "double-low areas" west of the line; moreover, "inefficiently-fertilized" areas were shrinking and "other-factor-influenced" areas expanding. (4) In the course, the coupling relationship between grain and fertilizer was dominated by "double-increase type" with other types positioning secondarily; and the relationship was mainly transforming towards "double-increase type" and "other-factors-affected type".