Effects Of Mowing On The Plant Community And Its Control Factor In A Stipa Krylovii Steppe Of Inner Mongolia

Mowing is a common practice in grassland management and play an important role in maintaining biodiversity, structure and functioning of grassland ecosystems. However, the effect of mowing on grassland ecosystem is not consistent. I conducted an8-year field experiment to examine the effect of mowing on a Stipa krylovii steppe in Inner Mongolia, China. The experiment consist of five treatments in terms of mowing height, i.e., control (non-mowing, Mck), extremely (2cm, M02), heavy (5cm, M05), moderate (10cm, M10) and light (15cm, M15), with five replicates. And all of the treatments were applied once a year in mid-August. Our result show that,1) The plant species responded differently to the mowing treatments. Extremely and heavy mowing significantly decreased the aboveground biomass of the dominant species of Stipa krylovii. and resulted in a decrease in the contribution of Stipa krylovii to aboveground net primary productivity (ANPP) of the community. For another dominant species, Artemisia frigida, its growth was negatively affected only by the extremely mowing but promoted by heavy and moderate mowing.2) At functional group level, extremely and heavy mowing have a detrimental impact on the performance of erect plants, while moderate mowing height favored growth of prostrate plants.3) The treatments decreased plant species richness over the period of the experiment except extremely mowing. Extremely and heavy mowing decreased the ANPP of the community. Overall, the community had a higher stability with the light mowing while it had a less stability with the extremely mowing.4) A correlationship analysis suggested that both ANPP and plant species richness are positively correlated with interannual variation in available precipitation.5) The stability of the plant community and Stipa krylovii population and Artemisia frigida population are positively correlated with interannual variation in available precipitation in moderate plots. In heavy plots there is a negative relationship between coefficients of variation in species richness and available precipitation.In conclusion, these findings reveal that a minimum mowing height of10-cm should be applied in order to maintain a high productivity and stability of the grassland.