The Effects Of Different Management Regimes On The ANPP、Belowground Biomass And Grassland Communities In Steppe Region Of Inner Mongolia, China

Grassland ecosystem is highly influenced by human activity, and sensitivity to global climate change. Reasonable grassland management regime plays an important role in maintaining grassland ecosystem function and service. Effects of different grassland use regimes on the aboveground net primary production and belowground biomass of a typical steppe community were studied in Inner Mongolia,2012-2014. The results showed no significant difference in ANPP among the enclosure, mowing and whole-season grazing grassland, but the composition of vegetation changed: Leymus chinensis expand its dominant position under enclosure, Stipa krylovii taken over Leymus chinensis gradually under mowing, and highly diversity of community showed under grazing pressure. Effects of different grazing regimes on the aboveground net primary production showed different results under different precipitation patterns. In a normal weather-year, start grazing in June led to a high ANPP; whereas in a drought year, deferring the grazing time to July resulted in a high ANPP. The results also show that plant belowground biomass showed no a significant difference among the grazing treatments as the grazing intensity was controlled by the residual height of grassland after each grazing, although the belowground biomass was more concentrated in the shallow soil layers. These results suggest that seasonal grazing at an appropriate grazing intensity has a positive effect on grassland production, and that residual height can be used as good criteria to control the grazing intensity. The time of initiating a grazing could be managed according to the current-year rainfall pattern for achieving a best sustainable grassland production.