关键词: 气候因子, 皖南花母猪, Am基因型, 繁殖性能

Abstract: Grasalands under various exploitation stages in the Yellow River Delta were examined quantitatively, and three equations were established between the variations of height, coverage and biomass of plant community and the accumulative development years. It was concluded that the height, coverage and biomass of plant community were reduced with time under the influences of over-grazing and excessive cutting. Corresponding measures should be adopted for protecting the grassland resources, e.g., separating grazing-and cutting areas, controlling the time and intensity of grazing and cutting, and reducing the amount of livestocks in the grassland.