基于GlobeLand30数据的中国耕地与粮食生产的时空变化分析

21世纪初期,中国耕地与粮食产量变化区域差异明显,为了解21世纪初期中国耕地与粮食生产的时空变化及粮食生产对耕地面积变化的响应,该文利用2000年和2010年两期30 m分辨率的全球地表覆盖数据(Globe Land30),借助统计分析手段对2000-2010年中国耕地和粮食生产的时空变化和粮食生产对耕地面积的依赖程度进行分析。结果表明:1)中国耕地主要分布在东部地区,研究时段内,耕地与林地、草地和人工表面之间的转换最多,耕地变化的特点是"西增东减,总量减少",面积净减少了104.03万hm2,年均减少10.4万hm2。2)中国的粮食生产主要集中在东北、华北和南方地区。粮食产量变化的特点是"北增南减,总量增加"。3)中国耕地分布的集中程度会影响粮食生产的集中程度,且粮食生产分布的集中程度普遍高于耕地。中国耕地分布重心和粮食生产分布重心的移动方向相反,耕地面积的分布表现出了"南退西移"的趋势,粮食生产的重心则是"北上东移",中国的粮食生产格局已转变为"北粮南调"。4)全国有32.24%县(市)的粮食生产都表现出了对耕地数量的依赖,主要分布在东北、华北、西部、长城沿线、西南和东南沿海地区。中国耕地保护政策的制定和粮食生产的可持续发展应该遵循因地制宜的原则,在粮食生产对耕地变化敏感性高的地区,应该加强对耕地数量、质量的保护和农户种粮积极性的提高,更要重视不敏感地区耕地地力的保护和单产水平的提高,以保障中国的粮食安全。

Spatial-temporal variations of cultivated land and grain production in China based on GlobeLand30

Abstract: To understand the spatial-temporal variations of cultivated land and grain production and the sensitivity of grain production in counties to cultivated land variation in China during 2000-2010, this paper analyzed the distribution, variation and the shifting of barycenter of cultivated land and grain production, and the response of grain production to the change of cultivated land by means of statistical analysis using the 30 m resolution global land cover data (GlobeLand30) in the year of 2000 and 2010. The results showed that: 1) Cultivated land was mainly distributed in the eastern region of China, and the variation of cultivated land was characterized by the increase in the west, the decrease in the east and the decline of total amount of cultivated land. And the net decreased area of cultivated land was 1 040 000 hm2, and the average annual decrease area was 104 000 hm2. In the conversion of other land types to cultivated land, the conversion of forest land, grassland and artificial surface to cultivated land was the most. The conversion between cultivated land and forest land was mainly concentrated in the southern region; the conversion between cultivated land and grassland was mainly distributed in the northeast, Inner Mongolia, Qinghai-Tibet area and the area along the Great Wall, and the ecological construction projects in these areas have achieved remarkable results; the conversion between cultivated land and construction land was mainly distributed in the North China Plain; and the reserve cultivated land resources in Xinjiang were rich, and the conversion between cultivated land and bare land was the most. 2) Grain production was mainly concentrated in Northeast, North China and South China, and the variation of grain yield was characterized by the reduction in the south, the increase in the north and the increase of the total grain output. 3) From the concentration degree of cultivated land and grain production, the concentration degree of cultivated land distribution affected the concentration degree of grain production distribution, and the concentration degree of grain production was generally higher than that of cultivated land. With the opposition of the direction that the barycenter of cultivated land moved, the barycenter of grain production moved toward the north and the east. The contradiction between grain supply and demand in China has increased, and the pattern of grain production in China has changed to "north-to-south grain diversion". 4) The grain production of 32.24% of counties showed the dependence on the quantity of cultivated land, which was mainly distributed in the northeast, North China, western region, the area along the Great Wall, southwest area and southeast coastal area. Grain output is not only affected by the quantity of cultivated land, but also affected by the sown area and the intensity of grain planting. In the areas with high sensitivity of grain production to cultivated land variation, we should strengthen the protection of the quantity and the quality of cultivated land and improve farmers'' enthusiasm of grain planting, and in the areas with less sensitivity, more attention should be paid to the protection of cultivated land fertility and the improvement of grain yield per unit area, so as to ensure food security in China. At the same time, the rotation and fallow can be implemented in less sensitive areas, to recover the land fertility without losing the grain production. This study also did the exploring work for the selection and allocation of rotation and fallow areas in China.