Study On Soil Respiration And Carbon Balance In Reclamation Area Of Coal Mine

Soil respiration rates and related environmental factors, soil microbial quantity, and soil enzyme activity for four types of vegetation (grassland, bushes, small arbors, arbors) were measured with Li-8100automated soil CO2flux system at reclamation district of coal mine located in Datong District Huainan City in January, march, July and October. The change law of release amount of CO2and its influencing factors were analyzed, and soil respiration intensity of different vegetation was also compared. At the same time, the fluxes of carbon fixation and carbon release for different vegetation were estimated using biomass inventory method and relative growth model. In order to maximize the carbon sequestration capacity in vegetation reclamation area, the net carbon fixation fluxes of different soil-vegetation system were calculated. The main results are as follows.1. The diurnal variation of soil respiration for four types of vegetation at reclamation-area showed a mode of single peak curve with the maximum value appearing in summer between12:00and16:00and the minimum value appearing in winter around4:00AM. Seasonal change was significant (p<0.05). The maximum appeared in July2012, the minimum appeared in January2012. The trend of soil respiration density under different types of vegetation was similar to the temperature of soil10cm and air temperature. The difference of the soil respiration intensity ratio of day and night is very small when compared with each other with an average of1.34.2. Soil respiration was extremely significant correlation only with soil temperature of10cm (p<0.05), and the effects of other environment factors were not significant (p>0.05). Exponential equation between soil respiration and soil temperature could explain more than88%of the soil respiration. The temperature sensitivity of soil respiration of the arbor forest was higher than the grassland.3. Rainfall had great impact on the soil respiration intensity of different types of vegetation. The first day after rain, soil respiration increased exponentially, then gradually decreased. The disturbance lasted about4days. Effect of Cinnamomum camphora was the largest of the four vegetation 4. The soil bacteria, fungi and actinomyces had the maximum in October2012, and had the minimum in January2012. All the soil enzyme activity was strongest in July, except for catalase, whose activity was strongest in October.5. The correlations of Soil respiration and soil bacteria, fungi, actinomycetes were not significant (p>0.05). The soil respiration of arbor forest was significantly correlated with the soil cellulase activity (P<0.05), and The soil respiration of small arbor forest was significantly correlated with the soil invertase activity and soil catalase activity (p<0.05). The soil respiration of bushes was not significant related to various enzymes(p>0.05), and the soil respiration of grassland was significantly correlated with catalase(p<0.05). The grassland at the reclamation had higher invertase and polyphenol oxidase activity than other types of vegetation. The soil invertase and cellulase showed high activity in bushes.6. The soil respiration under different vegetation types in the reclamation areas had significant difference (P<0.05), and followed a decreasing order of grassland, shrubs, small arbors and arbors. The soil respiration in arbor forest followed a decreasing order of Ligustrum lucidum Aiton, Ailanthus altissima, Cinnamomum camphora and Metasequoia glyptostroboides. The soil respiration in grassland followed a decreasing order of Amorpha fruticosa, Llex ciliospinosa, Buxus megistophylla and Pittosporum tobira. The soil respiration in arbor forest followed a decreasing order of Ophiopogon japonicas, Paspalum distichum, Cynodon dactylon and Eremochloa ophiuroides.7. Different filling did not cause differences in soil respiration, whether it was the reclaimed soil was the cause of differences in soil respiration intensity.8. The net annual carbon fixation of the arbor forest ecosystem is2.37t C·hm-2·a-1, the net annual carbon fixation of the small arbor forest ecosystem is1.68tC·hm-2·a-1, the net annual carbon fixation of bushes ecosystem is1.31tC·hm-2·a-1, the net annual carbon fixation of grassland ecosystem is0.38t C·hm-2·a-1. They all show Carbon Sink capability.