Effects Of Different Improving Measureson Degeneration Grassland Soil Carbon And Nitrogen Mineralization

In 2014-2015,this study to degraded Leymus chinensis grassland in Xilinhot Mao Deng as the research object, by the indoor thermostatic culture method and the cover of the in situ incubation method, the effects of different improvement measures （fencing, root-pruning, shallow plowing） on Degraded grassland soil organic carbon and nitrogen mineralization.We can draw the conclusion that:1. Root-pruning and shallow ploughing improvement compared with fencing, The mineralization rate of soil organic carbon in grassland was decreased.The variation trends:the earlier stage of cultivation maintained a high level, then it decreased rapidly, the end stage of cultivation remained relatively stable or rose slightly.2. Soil organic carbon mineralization decreased with the increase of soil depth, and mineralization of organic carbon in different soil layers were different. Different improvement measures,0-10cm soil carbon accumulation mineralization sequence:fencing> root-pruning> shallow plowing,10-20cm soil carbon accumulation mineralization sequence:root-pruning>shallow plowing>fencing.3. The relationship between soil carbon mineralization rate and organic matter is positively correlated. The order between the different improvement measures:fencing>root-pruning>shallow plowing.4.The various improvement measures cumulative mineralization of soil carbon with aboveground biomass was negatively correlated. In0-10cm, the cumulative mineralization of soil carbon with underground biomass was positively correlated, In10-20cm, he cumulative mineralization of soil carbon with underground biomass was negatively correlated.5. June to September, compared with fencing, root-pruning treatment increases soil net nitrogen mineralization rate, shallow plowing reduces the soil net nitrogen mineralization rate; The trends are gradually reduced. In June, the soil net nitrogen mineralization rate is the highest Respectively:0.38±0.11、0.23± 0.08mg.kg^-1.d^-1; the september is the lowest, Respectively:-0.01±0.03、-0.03± 0.04mg.kg^-1.d^-1.