The Effect Of Mowing Systems On The Community Characteristics And Restoration Succession Of Different Improvement Measures On Degraded Grassland

In the research, Chinese Academy of Science Inner Mongolia Grassland Ecosystem Research Station took the recovered grassland that was conducted fencing enclosure and shallow plowing meliorative treatment in 1983 and has not been conducted other human disturbance for 22 years (from 1983 to 2005)as the research objective. In 2005, the Station arranged the mowing system research experiment of mowing measures, and had carried out 11-year (from 2005 to 2015) field located monitoring of mowing process of different mowing system, and conducted statistical analysis of plant community density, biomass, community function composition, community succession pattern, community structure changes and other aspects, drawing the following conclusions:1. Shallow plowing improvement measure is benefit for the rapid recovery of forage yield, but in the perspective of long-term ecological restoration, the shallow plowing is not the best method for improving degraded grassland. In a larger time scale, the hysteresis of fencing enclosure disappears.2.The community densities of three mowing systems on the basis of shallow plowing improvement measures show a trend of rising at the early stage of mowing, declining at the medium stage and rising again at the later stage; compared with the control treatment (not mowing), the community density of early stage of mowing treatment is higher. The density of rhizome grass begins to decline after 4 to 5 year’s mowing treatment, and then the living space of Leymus chinensis start to expand and appears recovery of different degrees when the density of rhizome grass declining to a certain extent; compared with the control treatment (not mowing), the community density of mowing treatment is higher, indicating that mowing is conductive to the maintenance of rhizome grass.3 The community densities of three mowing systems on the basis of shallow plowing improvement measures biomass shows a trend of increasing at the medium stage and declining at the later stage. Compared with the control group, biomass of mowing treatment shows the trend of overall declination except several years at medium stage, in which the density of bunch grass declines significantly.4. The community densities of three mowing systems on the basis of fencing enclosure recovering measures shows a trend of rising, but lower than the control treatment of not mowing. The density of rhizome grass reflects a rising trend, but still lower than the control treatment.5. On the basis of fencing enclosure recovering measures, total community biomass and biomass of rhizome grass reflect a rising trend, respectively, and compared with control treatment (not mowing); with the increase of mowing density, the biomass of rhizome grass shows declining of different degree compared to the control, yet the declining is not significant. With respect to shallow plowing, the anti-mowing interference ability of fencing enclosure is much stronger.6. Upon the treatment of shallow plowing, the sort of grass damage rate is "two-year cutting with one year internal< one year cutting with one year internal< cutting once a year7.Different mowing regime mowing process 11, changed the shallow plowing and fencing improvements inherent natural restoration succession direction, and demonstrated by the succession is not the same trajectory.8. The two kinds of improved recovery measures, the similarity coefficients are cutting other year> cut two years off year> cut once a year. The community showed less interference, and not mowing mowing community control community composition more similar.