| To explore the urban lawn ecosystem carbon sequestration-source balance characteristics in Jianghuai Area. In Hefei City area growth one year, three years, five years and five years in depression and under forests of Zoysia Marcella grass were studied through field experiments one year of determination, results show that:1The average soil organic carbon and soil carbon density increased with growth years of Zoysia Marcella grass in0-20cm soil layer. The soil organic carbon(SOC) under1year,3years,5years lawn was5.83、6.42、10.25g/kg and the mean density of SOC was1.60,1.54,3.12kg/m2. The SOC and the mean density of SOC under five year forest land, depression land and blank space land were5.02、5.77、11.22g/kg and1.42、1.80、2.55kg/m2in0～20cm soil layer. Comparison shows that the Soil organic carbon and organic carbon density maximum forest-lined lawn, in addition, all soil SOC content and density increased with soil thickness decreased.2The vegetation biomass of1year,3years,5years Zoysia Marcella lawn was0.50、0.97、1.53kg/m2, and vegetation carbon storage was0.23、0.50、0.74kg/m2. The vegetation biomass and vegetation carbon storage of depression land, forest land, grass land were1.22n、0.86、1.53kg/m2and0.67、0.58、0.74kg/m2. Vegetation biomass and carbon storage with lawn planting years increasing obviously. The underground part and the total vegetation carbon storage difference between grass land, depression land and forest land is not significant, and the ground vegetation carbon storage difference is significant. Variety of lawn between carbon storage is grass land> forest land> depression land in turn.3Through determination of lawn soil respiration rate throughout the whole year, confirmed that the seasonal variations of soil respiration rate was obviously, the lawn soil respiration rate maximizing in summer and autumn and difference is significant, while is not significant in spring and winter, the lowest values occurred in winter. Soil respiration of the highest daily mean rate appeared in summer five years grassland (14.40μmol·m-2·s-1), the lowest rate was one year grass land (0.64μmol·m-2·s-1), the respiratory rate under year daily showed a single-peak curve change. There was a significant correlation between soil respiration rate and surface temperature. The relative humidity of the soil pores and surface temperature has a synergistic effect with soil respiration, the correlation coefficient of soil respiration and relative humidity decreased with years of growth, soil respiration rate was mainly controlled by soil void the influence of relative humidity in the initial growth, is mainly affected by the soil surface temperature after growth period.4The CO2emissions of Zoysia Marcella have certain differences in each month throughout year, the maximum rate was five years grass land in July (0.402kg/m2), and the minimum value was February blank space (0.006kg/m2). The CO2emissions of every land showing a high in summer and autumn, and low in spring and winter. The emission under depression land was less than the forest land in the rainy season and other months was more than the forest land. The maximum emissions land was five years grass land (0.13kg/m2) and the minimum value was blank soil. The net amount of carbon under grass land, forest land, depression land was respectively0.13、0.55、0.83kg/m2. Zoysia Marcella lawn exercise the carbon sink function of the city in the carbon cycle system but with the carbon sequestration capacity of planting years growth uncertainty. |
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