Effects Of Different Mowing Methods On Plant Community Succession And Interspecific Relationship In Restored Degraded Grassland

Unreasonable mowing is one of the main causes of grassland degradation.In order to study the effect of different mowing methods on restoration succession of restored degraded grassland.After 22 years of fenced restoration,a mowing experiment was carried out in the Inner Mongolia Steppe Ecosystem Positioning Station of the Chinese Academy of Sciences in 2005 with four mowing methods: two-year cutting with one year internal,cuting once a year with stubble height of 6cm,cuting once a year with stubble height of 10 cm,one year cutting with one year internal,natural recovery as a control.To study the dynamics of community characteristics of basically restored degraded grassland under mowing and reuse,the effects of mowing utilization on natural succession and interspecific relationship of grassland were discussed.The results were as follows:(1)The succession stage of natural recovery can be divided into dominant stage of Artemisia frigida(degenerate community variation),the dominant stage of Artemisia frigida + Agrophylla miltifolia,the dominant stage of Agropyron michnoi and the dominant stage of Leymus Chinensis.Different Mowing methods changed the original inherent direction of succession.The plant community eventually became Carex korshinskyi + hybrid grass + Achnatherum sibiricum.Mowing resulted in different degrees of redegradation of the recovered plant community.The degree of degradation increased with the increase of mowing intensity.(2)Mowing changed the relationship between species pairs in the community,and the number of main species pairs that attracted or repelled each other increased with the increasing mowing intensity,leading to the weakening of community stability.Compared with other mowing methods,the relationship between the same species was weaker,and the community was more stable due to the lower sensitivity of community species to resource utilization.(3)Compared with control,all the four mowing methods significantly(P<0.01)reduced the standing biomass of the community.The standing biomass of perennial tufted grass was significantly(P<0.05)higher than that of the control.The standing biomass of other perennials was significantly(P<0.01)lower than that of the control.The standing biomass of rhizomes,shrubs and subshrubs was lower than that of the control,but there was no significant difference among different cutting methods.Mowing resulted in some complementarity between the standing biomass of perennial tufted grass and other perennials.(4)The mowing method with two-year cutting with one year internal had the highest yield,Shortterm mowing with two-year cutting with one year internal was beneficial to the rapid increase of grass yield,but long-term and intensive mowing will lead to premature drought and gradual degradation of plant communities.Cutting once a year with stubble height of 10 cm has better ecological and economic benefits.