The Effect Of Different Restoration Measures On Degraded Grassland In Songnen Plain

At present,Songnen grassland degraded severely,rebuilding and restoring of these degraded grassland is an urgent need.Basing on the situation of Songnen degraded grassland,in 2002,we carried out a series of restoration measures , including harrowing and seeding Hordeum brevisubularum(Trin.)Link,splitting and seeding Echinochloa crusgalli,inserting corn stalk and enclosure. For learning about the effects of theses measures on different degraded grassland and making proper restoration way for Songnen degraded grassland,we perform three surveys in this paper,including the effects of different restoration measures on highly degraded grassland in Songnen plain,the effects of enclosure for some years on three dominant species communities of degraded grassland in Songnen plain,the effects of different time enclosure on Aneurolepidium chinensis community of degraded grassland in Songnen plain. The major conclusions are as below:1. Every restoration measure has effect on checking future degradation and restoring highly degraded grassland,in which the most effective method is enclosure,this way can improve the community and soil characteristics largely,then is splitting and seeding Echinochloa crusgalli measures. Enclosure improved effectively the vegetation cover,vegetation height,aboveground biomass in three degraded grassland communities,the Leymus chinensis community had best representation to enclosure. Enclosure promoted degraded Leymus chinensis community development to maturation and stabilization. from 4 years to 6 years for enclosure,enclosure improved vegetation of Leymus chinensis grassland,especially after 6 years for enclosure,the vegetation characteristics had come or reached the level of healthy grassland.2. The soil chemical and physical characters of three communities inside and outside the fence were not different markedly after enclosure. Except for soil pH and total N content,the enclosure for different time had not positive effect on other soil chemical and physical characters of degraded Leymus chinensis community in this experiment. Regarding the soil condition,the restoration of degraded grassland in Songnen plain need much time.3. In this region,as a result of good climate condition and precipitation compared with arid environment,even if when grassland degrades severity,enclosure is the best restoration method.4. As the factors which have common contact with other indexes,aboveground biomass of community,surface soil pH and conductivity rate can be used to evaluate the situation of degradation or restoration of Leymus chinensis grassland.