Influence of grazing intensity on the aboveground biomass and nutrient dynamics of community

Three grazing intensities were applied on Zhaosu Army-Horse Farm to compare variations of aboveground biomass and nutrient contents of plant community from 2011 to 2012. The results showed that aboveground biomass decreased under each treatment with extension of grazing time. For aboveground biomass, there were significant differences between different grazing treatments and the control area with the extension of grazing time in every year (P＜0.05). The crude protein contents of Thymus asiaticus, Medicago falcate, Carex liparocarpos, Stipa capillata and Festuca ovina decreased with the extension of grazing time, whereas there was no significant difference among different treatments. The dry matter contents of these 5 dominant species decreased and then slightly increased followed by further decrease during the whole grazing period although the fluctuation rate was 0.01%～2.00%. The neutral detergent fiber and the acid detergent fiber of these 5 dominant species increased with slightly decreased in the middle of grazing time. These observed variation of aboveground biomass and nutrient content showed that moderate grazing had less influence which was better for sustainable development of grassland. The effects of different grazing intensity on aboveground biomass and nutrient were far less than the effects of Inter-annual climate change.