SOIL DEGRADATION:A GLOBAL PROBLEM OF ENDANGERING SUSTAINABLE DEVELOPMENT

Soil degradation, defined as lowing and losing of soil functions, is becoming more and more serious worldwide in the last decades, and exerts a thread to agricultural production and terrestrial ecosystem. It is estimated that nearly 2 billion hectares of soil resources of the world have been degraded, namely around 22 percent of all cropland, pasture, forest, and woodland. Globally, soil erosion, chemical deterioration and physical degradation are the important forms amongst various types of soil degradation. As a natural process, soil degradation can be enhanced or dampened by a variety of human activities such as inappropriate agricultural management, overgrazing and deforestation, etc. Degraded soil means less food. As a result of soil degradation, it is estimated that about 11.9 ～13.4 percent of the global agricultural supply has been lost in the past five decades. Besides, soil degradation is also associated with off site problems of sedimentation, climate change, watershed functions, and changes in natural habitats leading to loss of genetic stock and biodiversity. Therefore, it is quite essential to combat soil degradation at different levels and scales worldwide, not only for food security and ecological health, but also for guarantee of global sustainable development.