Effects Of Different Cutting Frequency On Community Characteristics And Compensatory Growth Of Stipa Grandis Steppe In Inner Mongolia

The research object of this research is the Stipa grandis steppe in Inner Mongolia XilinGol League, made research about the community characteristics、soil physicochemical properties、compensatory growth of the dominant species of the Stipa grandis steppe responseing to different cutting systems. Results indicated that:1.The community total density in fencing S. grandis community was significantly lower than in cutting S. grandis community, the community total height and the community total biomass in fencing S. grandis community was significantly higher than in cutting S. grandis community; the important value of Stipa grandis would reduce and the important value of Leymus chinensis and Anemarrhena asphodeloides would escalate in the community with higher frequency cutting; the different cutting systems had no significantly affect to Shannon-wiener index and no affect to Pielou index.2. The influence of the different cutting systems to the density and biomass of Stipa grandis、Leymus chinensis and Anemarrhena asphodeloides and to the height of Leymus chinensis and Anemarrhena asphodeloides in the community was not significantly, but there had significantly influence that the different cutting systems to the height of Stipa grandis in the community. The individual biomass of Stipa grandis and Anemarrhena asphodeloides in fencing was significantly higher than in cutting at the early growing season and the individual biomass of Leymus chinensis in fencing was significantly higher than in cutting at the whole growing season.3. The soil organic matter content in the underground20-30cm and30-40cm and the soil total nitrogen in the twice one year cutting was significantly higher than other cutting systems and fencing. The soil available nitrogen and soil available phosphorus content had no significantly different to different cutting systems and fencing.4. There was significantly difference of the community soil respiration rate to different cutting systems, cutting interval year and fencing was significantly higher than other systems, and the soil respiration rate was the lowest in early July for all systems. The soil bacteria and soil microbial in fencing was significantly higher than cutting systems, once one year was significantly higher than other systems; the soil actinomycete in cutting interval of two years was significantly higher than others in June, once one year was significantly higher than others in July, the fencing was significantly higher than cutting systems in August.5. The growth height of Stipa grandis、Leymus chinensis and Anemarrhena asphodeloides in fencing and cutting was nearly highest after60days; after90days, the growth height was founded to reduce. After different growth time, the growth height of Stipa grandis、Leymus chinensis and Anemarrhena asphodeloides in fencing and cutting interval year was significantly higher than other cutting systems. The CH of. Stipa grandis、Leymus chinensis and Anemarrhena asphodeloides in fencing was significantly higher than other cutting systems and in once one year was significantly higher than the other cutting two systems; the RGR and the compensatory biomass had no significantly difference to different cutting systems.6. The constructive species could grow better and occupy more resources. Enduring fence had significantly beneficial to soil microbial, soil nutrients and soil respiration, but not conducive to the growth of dominant species, the community species diversity and increasing of the community density. Combining the actual production and Long-term using, the cutting interval year is the most reasonable use type.