Research On The Effect Of Different Restoration Measures On Degenerated Leymus Chinensis Steppe

The long-term human interference caused by the grassland degenerated extensive, serious, resulting in poor production and ecological consequences. So people try to take measures to improve the variety of rehabilitation, including natural restoration and agricultural measures (harrowing, shallow ploughing, irrigation, fertilization and so on), different measures have played a positive effect. But the past research has focused on the single factor effect, this experiment for the first time by combining multiple measures, designed root cutting+irrigation+fertilization, root cutting+irrigation, root cutting+irrigation, root cutting, shallow ploughing and contrast. In addition to the experimental studies not only the different restoration measures in production and community structure of community restoration succession, also study the effects of different treatments on soil organic carbon density. The plant root cutting treatments in this experiment and the1983harrowing processing community succession pattern similarity, so as to build long-term artificial processing Degenerated Steppe of Leymus chinensis restoration succession model of a special30years of research on the plant community restoration succession.The main results are as follows:1、The five measures can be in two years ago to improve community aboveground biomass, but the increase is not the same; When the root cutting, irrigation, fertilization three combined increase production effect is best, compared to2012,2013two years community yield available: precipitation is still a typical steppe community aboveground biomass determinants;2、Shallow tillage layer (0-10,10-20cm) bulk density values were significantly lower than those of control, and the layers of the20-100cm is overall slightly higher than the control, indicating that the shallow ploughing can decrease soil bulk density, but the decrease was deep in the bulk density increased costs; root cutting treatments can reduce soil bulk density0-10cm, to loose soil the objective, but this effect is increased to10-20cm bulk density values for conditions;3、The soil organic carbon density in0-30cm layer, shallow tillage was decreased11.09%,14.17%and12.27%respectively, each layer of30-100cm were no significant change; the rest of the each layer0-10cm and the photo was slightly lower but not significantly, each layer of the20-100cm no significant difference with the control;4、30years of community restoration succession process, which show a downward change obviously increased after the first species, the rise in treatment of invasive plants one or two years earlier, from decline in free competition a biennial plant was gradually replaced by more competitive perennial grasses;5、In30years the community density appear first wave rise after severe decline gradually stabilized, the rise in Gramineae plants through proliferation and occupy more niche, stable source to after fierce competition after the community succession of stationary; change from30years of community species diversity and evenness of increased first and decreased and then gradually stable, the decline stemmed from dominant grasses growing degree, stable source in population pattern tends to be stable after full competition;6、Degenerated steppe of Leymus chinensis restoration succession progress of30years can be divided into four stages:The first stage was a community of A. frigid+L.chinensis+Lower bunch grass (1year after harrowing).The second stage was a community of L.chinensis+A.cristatum+annual or biennal forbs (2-3years after harrowing).The third stage was a community of L.chinensis+.crstatum+perennial forbs transitional (4-22years after harrowing). The forth stage was a community of L.chinensis+S. grandis+bunch grass (23-30years after harrowing).