The Effect Of Different Improving Measures On Degenerated Steppe Of Leymus Chinensis

Making comparisons of community characteristic after different improving measures (seeding Leymus chinensis,ploughing,harrowing,fencing ) on Degenerated Steppe of Leymus chinensis,in 1983.By comparing to evaluate the different measures,providing a scientific basis for the restoration of degraded grassland and improving productivity of grassland,to seek a best way to restoration of degraded grassland.1.The physical and chemical properties of soil have improved,although after 23 years restoration.The soil conditions are different.The soil bulk density after seeding Leymus chinensis,ploughing,harrowing,fencing are reducing by 10.81%,22.30%,21.62%,11.49%,compared with the outside fence respectively,but ploughing and harrowing are obviously higher than seeding Leymus chinensis and fencing.Moisture water content after seeding Leymus chinensis.Ploughing,harrowing,fencing are improving by81.68%,93.71%,91.36%,86.39%,there existed no significant difference between different improving measures.2.The number of bacteria in L1 soils after ploughing,harrowing,seeding Leymus chinensis.,fencing are increasing by 91.56%,89.66%,87.36%,73.56%,compared with the outside fence respectively,but there existed no significant difference between different improving measures.The number of fungi are increasing by 53.06%,50.34%,50.34%,22.45%,but the fence is obviously lower than the other measures;The number of actinomycetes are increasing by 53.06%,50.34%,50.34%,22.45%,but ploughing and harrowing are obviously higher than seeding Leymus chinensis and fencing.So ploughing and harrowing is more advantageous to increase the quantity of microorganism.3.The community biomass after ploughing,harrowing,seeding Leymus chinensis.,fencing are increasing by 127.30%,146.64%,138.04%,compared with the outside fence respectively;but the community biomass after seeding Leymus chinensis,are obviously lower than the other improving measures.The different improving measures have different influence to community function group composition.Rhizome grasses biomass is highest after ploughing 51.88g/m~2,occupying the community total biomass 34.47%;Bunch grasses biomass is highest after fence 50.04 g/m~2, occupying the community total biomass 30.27%.4.The seasonal dynamics of aboveground biomass is a growth curve with single apex,and the forms of the curve were similar under different treatment;The rate of dry weight had obviously changed with season and was higher at the initial and later stages;There were negative correlation between The rate of dry weight and soil moisture water content. It comes to a conclusion the effects of ploughing and harrowing last the longest time,but other measures still exist aftereffects.