Present Research Status on Methods to Prevent Desertification

抄録

Arid and semi-arid lands account for one third of all land on earth. Desertification is now prevailing and is occasionally linked to the decrease of rainfall due to climatic change, however, it is mainly linked to the adverse human impact i. e., over-cultivation, grazing, deforestation and consumption of water resources.
The United Nations Conference on Desertification (UNCOD) was held at Nairobi, Kenya in 1977, and the Plan of Action to Combat Desertification (PACD) was adopted. Countermeasures against desertification have been carried out in many countries since the conference. However, the effects have not yet met expectations. It is a fact that desertification is still growing significantly.
There are various prevention methods against desertification. They are divided into two countermeasures, i. e., one is social countermeasures with political, economical and educational procedures and the other is technical countermeasures using physical, chemical, biological and ecological techniques. The author presents the research situation regarding the latter cases, prevention methods using (a) windbreaks, (b) covering or mulching by vegetation, films and chemicals (e) irrigation and so on. A concrete prevention technique is introduced as a case study of environmental control or meteorological improvement in China, particularly at Turfan.