Abstract: A series of comparative sampling plots were selected to study the effects of different grazing intensities on the biodiversity and productivity of a  Leymus chinensis meadow steppe in Inner Mongolia. It was shown that with the increase of grazing intensity, α diversity index decreased after an initial increase, and had the highest value in light grazing areas, which supported the ‘medium disturbance theory’, while β diversity index had an increasing trend. Lesser similarity of plant species was observed under different grazing intensities. There was a significant linear relationship between aboveground net primary productivity (ANPP) and Alatalo evenness index (P<0.05). Grazing and climate had larger effects on the ANPP, but their interactive effect was not significant. No grazing could not maintain grassland health, but healthy grassland could effectively buffer the disturbances of grazing and climate, and maintain its higher productivity and biodiversity.

Key words: Colloid minerals, Adsorption, Acetic acid, Acid phosphatase