改革开放以来中国粮食生产空间重构

The grain production space reconstruction in China since the reform and opening up

粮食生产空间重构不仅事关我国粮食安全,而且深刻影响着区域经济发展与生态保护。从数量、生产潜力和空间格局三个维度出发,采用GAEZ模型、景观格局指数与重心迁移模型探讨了1980—2018年中国粮食生产空间重构。研究表明:(1)就数量来看,南减北增,总量基本持衡,但其内部转换频繁。粮食生产空间转出面积约达6458万hm^(2),其中退耕还林还草与建设用地扩张占到90%左右;粮食生产空间转入面积为6680万hm^(2),毁林垦草占到75%。(2)从生产潜力上看,其总量整体呈下降趋势,同时表现出由东向西降低的梯度差异。生产潜力总量减少主要是由退耕还林还草与城市扩张所导致,使得中低潜力、中潜力与中高潜力等级的粮食生产空间减少。而增加的主要原因是毁林垦草,使得中潜力与中高潜力等级的粮食生产空间大量增加。(3)由于人类活动的加剧,空间格局发生了显著变化。粮食生产空间的规模逐渐变小,形状趋于复杂,相隔距离逐渐变远。同时,粮食生产空间的数量重心整体向南运动,但迁移距离不大。而生产潜力重心不断向东北移动,迁移幅度相对较大。研究结果丰富了土地系统研究体系,为保障粮食安全及实现粮食生产空间的可持续集约化发展提供依据。

Grain production space reconstruction not only concerns China’s food security,but also has a profound impact on regional economic development and ecological protection.From three dimensions of quantity,production potential and spatial pattern,the paper employs GAEZ(Global Agro-Ecological Zones)model,landscape pattern index and gravity center model to discuss the grain production space reconstruction of China from 1980 to 2018.Studies have shown that:(1)In terms of quantity,grain production space gradually decreases from south to north,and the total area remains almost unchanged,but it has frequent internal conversion.The grain production space has been transformed into other land use types,amounting to about64.58 million hm^(2),of which the Grain for Green and construction land expansion account for roughly 90%.The other land use types have been converted into grain production space,reaching 66.8 million hm^(2),of which deforestation and grassland reclamation account for 75%.(2)From production potential,the total amount showed decreasing trends in the past 40 years,while the spatial distribution presents a pattern of"high in the east and low in the west",showing an obvious gradient difference from east to west.The decrease of total production potential of grain production space was mainly caused by the Grain for Green and construction land expansion,resulting in the decrease of grain production space with medium-low,medium and medium-high potential levels;However,its total increase was mainly attributed to the deforestation and grassland reclamation,leading to an increase of grain production space with medium and medium-high potential levels.(3)Due to the aggravation of human activities,the landscape pattern of China’s grain production space has undergone significant changes since the 1980 s.Its scale gradually decreased,the shape tended to be complex,and the distance gradually became far.Meanwhile,the quantity gravity center has moved southward,but not too far.The gravity center of its production potential has been moving to the northeast,with a distance of 82.74 km.This paper enriches the research setup of land system,and provides the basis for guaranteeing food security and realizing food production space’s sustainable and intensive use.