Abstract: The study on the plant diversity and aboveground biomass of Stipa baicalensis grassland under different grazing intensity showed that with increasing intensity of grazing, the plant cluster of S. baicalensis population fragmented and miniaturized; while Leymus chinensis had stronger capability in enduring grazing, and its aboveground biomass was the highest under moderate grazing. The primary biomass of the grassland community decreased with increasing grazing intensity. Under higher grazing intensity, the weeds worse for feeding and with higher capability in enduring grazing increased. When the grazing intensity increased continuously, the population would be replaced by the weeds. The stability of the grassland population also decreased with increasing grazing intensity, but the effects on the population diversity, aboveground biomass, and stability were not synchronous and symmetry. There was a rapid and intensive response of the primary biomass of the grassland community to grazing disturbance.

Key words: Rice straw, Quick decomposing, Chemical biological combined decomposing technique, FTIR spectroscopy