在世界许多地方,陆地旱化面积不断扩大已成为一个严重的问题。土壤干旱导致养份流失,肥力下降,再也不能种植庄稼、树木和牧草。联合国环境规划署称,生活在干旱地区的9亿人口正受到陆地旱化问题的威胁。人口增长、动物太多、过度放牧、水蚀风化和滥伐森林等,都是使土地生产能力日益下降的原因。在过去50年中,人类活动破坏了相当于中国和印度两国国土面积之和的土地,全球约有1/4的陆地面临沙漠化的危险。非洲2/3的人口生活在干旱地区,而这些地区70％以上用于耕种 In many parts of the world, the expanding area of ​​dry land on land has become a serious problem. Droughts in the soil lead to loss of nutrients and fertility, and can no longer grow crops, trees and pastures. According to the United Nations Environment Program, the 900 million people living in arid areas are threatened by the problem of dry land on the land. Population growth, too many animals, overgrazing, water erosion and deforestation are the reasons for the declining production capacity of the land. For the past 50 years, human activities have destroyed land equivalent to the sum of the land areas of China and India. About a quarter of the world’s land is at risk of desertification. Two-thirds of Africa’s population lives in arid areas, while more than 70% of these areas are used for farming