| The open-pit coal mining results in a decrease in soil carbon sequestration capacity,and the reclamation work can significantly increase the soil carbon storage,nutrient contents and enzyme activities in the mining area.The effects of different reclamation modes on soil carbon sequestration capacity and fertility recovery are inconsistent with the time of reclamation.This paper selects six plots under the reclamation pattern of grassland and farmland as the research object.At the same time,the soil under nature restoration and original landform plots were collected as control soils.The profile characteristics of soil organic carbon fractions,soil nutrient and soil enzyme activities in different reclamation models of different years were studied.In order to obtain scientific data and provide the basis for selecting reasonable reclamation mode in the mining area.The results of the study are as follows:(1)The contents of total carbon and organic carbon fractions in the 6 plots of grassland and farmland reclamation patterns generally decreased with the increase of soil depth.The 0-10cm carbon contents in the surface layer of the reclaimed 20 years was significantly different from that of the bottom layer.Compared samples of different reclamation time from the same soil layer found that the contents of total carbon and organic carbon fractions in the reclaimed land for 20 years is higher than that of 8 years and 3 years.The carbon contents of the reclaimed land for 3 years is generally higher than that of spontaneous recovery plots.The plots after 20 years reclamation in the grassland pattern,the contents of other organic carbon fractions in the surface soil 0?10cm were higher than those in the original plots.However,The plots reclaimed for 20 years in the cultivated pattern,except for the easily oxidized organic carbon,the contents of other organic carbon did not reach the original plots' in the surface 0-10 cm.(2)Selection of typical plots and soil layers of reclaimed soil for analysis of DOC three-dimensional fluorescence and UV spectral characteristics.Calculate the values of fluorescence index(FI),freshness index(?/?),and humic index(HI)of the three-dimensional fluorescence spectrum,and the SUVA 280,SUVA 254,E 250/365,and E 253/203 in the UV spectrum.It was found that the aromatization and humification degree of DOC in 0?10cm soil layer were higher in alfalfa land that has reclaimed for 20 years.At the same time,the complexity of the DOC structure was increased.And improve the soil organic matter content and carbon sequestration capacity.The soil surface is more carbon sequestration than the bottom layer,and the longer the reclamation time is,the more the soil carbon accumulation is.(3)Soil nutrient content and soil enzyme activity were consistent with the results of soil carbon studies.Except for the content of total phosphorus,available phosphorus and the activity of catalase,the other indexes were decreasing with the increase of soil depth.However,with the reclamation time increasing,the available K and total K decreased first and then increased in grassland reclamation model,while the reclamation pattern of cultivated land gradually increases with the reclaimed years.The value of the 0?10cm soil layer in the 20 years of reclaimed land was significantly higher than that of the remaining soil layers.(4)Based on a comprehensive analysis,in the Antaibao Opencast Mine,grassland and farmland reclamation models have a certain effect on soil carbon sequestration and fertility recovery.In particular,20 years of grassland reclamation can significantly increase the soil carbon accumulation and nutrient contents,and the reclamation effect is better,which is better than the farmland reclamation model. |
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