Study On Carbon Dynamics Of Reclaimed Soil In Coal Mining Subsidence Area With High Groundwater Level

Dynamic changes of soil carbon pool research has always been the hot spot of the academic research. The characteristics of soil carbon pool for us to understand the status of the soil development and the status of soil quality has important significance. The environmental change of reclaimed soil in coal mining subsidence area is huge. These man-made factors have a great disturbance on soil environment, which deeply influenced reclamation area soil carbon pool features. Study of dynamic properties of reclamation soil carbon pool, for us to understand the development situation of soil after reclamation, the evolution of soil quality characteristics and the stability of soil carbon pool mechanism has important significance.(1)Analyze the evolution of soil physical and chemical properties of reclaimed soil.After reclamation, the maximum soil conductivity is 609 us/cm. The phenomenon of soil salinization won’t happen. But it has a tendency that with increasing reclamation time the soil conductivity increasing towards to the direction of groundwater. After reclaimed for 13 years, soil organic matter and total nitrogen content is up to the level of the normal farmland. Compared to the soil nutrient index in forest land and abandoned land, it is higher in arable land.(2)Research the evolution of soil carbon library of reclaimed soil. The total carbon content of reclaimed soil is higher than it in control soil. Up to 95.29%, soil inorganic carbon takes the largest part of soil total carbon.With time went on, total soil inorganic carbon had been decreased and total soil organic carbon ratio had been increased. After reclaimed for 12~13 years, soil organic carbon content of arable land reached to the control level. After the reclamation, there had a tendency that soil microbial biomass carbon content increase year by year. 10 years later, reclaimed arable land soil microbial biomass carbon can reach to the normal level. Soil microbial entropy has been increasing, and it proved that soil microbial living environment is improving. The soil microbial biomass carbon and soil microbial entropy are higher compared to forest land and abandoned land.(3)Discuss the evolution of the foundation soil respiration of the reclaimed soil.After the reclamation, the based breathing flux due to the differences between the soil characteristics exist significant differences. During the early period of reclamation, soil environment were more conducive to soil microbial respiration.Along with the increasing length of reclamation, the soil microbial metabolism entropy decreases gradually. After 12~13 years reclamation, there was no significant difference between reclaimed arable land and normal farmland(P < 0.05).It was significantly lower than that of forest land and abandoned land.