Grassland Degradation, Construction and the Economic-technological Strategies of Sustainable Development of Grassland-agriculture

摘要

Natural grassland in the West of Northeastern China is located in 40° 0′ - 43° 5′ N latitude and 117° 0′ -127° 5′ Elongitude. It lies in the Lisp River Valley, the Songhua River Valley and Nen River Valley. About 130 years ago, this region had rich natural grassland resources, was numerically 26.67 millions in hectare of grasslands.Since the last stage of Qing Dynasty, the grassland has been destroyed seriously in 3 times. Up to now, this region only preserved about 2 millions in hectare of the grasslands. In addition, 3.33 millions in hectare of the grasslands have changed from primary grassland to desertification, salinizatio-nalkalinization and degeneration grasslands in the form of patches of bare soil (their simple form of a name is "3 kinds of degeneration grasslands"). This paper indicaed that in any period both grasslands destruction and its restoration were relevant to economic changes and economic systems,particularly to market economy in that time. The following agricultural economic-technological strategies have been production bases of concentrated feed crops and coarse herbage crops.