2000—2020年非洲耕地资源时空格局变化分析

Spatial-temporal pattern changes of cultivated land resources in Africa from 2000 to 2020

非洲地区面临严重的粮食安全问题,研究其耕地资源时空格局变化对于保障非洲粮食安全具有重要意义.基于2000—2020年间联合国粮农组织的统计数据,通过重心迁移、标准差椭圆及局部空间自相关等方法对非洲耕地资源时空格局的变化特征进行了分析.结果表明:1)非洲耕地整体数量呈稳定上升趋势,20年间耕地面积增加了6321.92万hm^(2),增长率为53.44%,但不同国家间存在差异;2)非洲耕地在几何中心以北区域分布较多,耕地重心迁移方向先向东北后转向偏西方向,移动总距离为111.86 km,偏移速率先快后慢,从前5年的平均10.27 km/a降至后15年的平均4.00 km/a左右;3)非洲耕地分布呈西北—东南向,20年来标准差椭圆转角有向水平方向倒伏趋势,椭圆面积不断缩小,向心性不断增强;4)非洲耕地分布集聚主要出现在西非的尼日尔和尼日利亚,异常区为南非及贝宁.

Africa was facing serious food security problems,and it was of great significance to study the temporal and spatial pattern of cultivated land resources to ensure food security in Africa.Based on the statistical data of Food and Agriculture Organization of the United Nations(FAO)from 2000 to 2020,the spatial-temporal pattern of cultivated land resources in Africa was explored by means of center of gravity transfer model,standard deviation ellipse,and local spatial autocorrelation.The results showed that:1)The overall number of cultivated lands in Africa showed a steady upward trend,with an increase of 6.32×10^(7)hm^(2)in the past 20 years,with a growth rate of 53.44%,but there were differences among different countries;2)The cultivated land in Africa was widely distributed in the north of the geometric center.The gravity center of cultivated land generally moved to the northeast and then turned to the west,with a total distance of 111.86 km.The migration rate was first fast and then slow,from 10.27 km/a in the previous 5 years to about 4.00 km/a in the next 15 years;3)The cultivated land in Africa was distributed in the northwest southeast direction.In the past 20 years,the standard deviation ellipse angle had a trend of lodging in the horizontal direction.The ellipse area was shrinking,and the centripetalism was increasing;4)The distribution and concentration of cultivated land in Africa mainly situated in Niger and Nigeria in West Africa,and the abnormal areas were the Republic of South Africa and Benin.