Effects Of Plant Planting On Soil Aggregates And Organic Carbon In Reclaimed Soil

In the process of large-scale coal mining in China,the ecological damage is more serious,causing a series of problems such as farmland damage and soil degradation,etc,therefore the land reclamation and vegetation restoration had become one of the most urgent tasks.The key ways of land reclamation are the reconstruction of soil physical and chemical properties,and aggregates and organic carbon as the key indicators of land reclamation effect evaluation,which distribution and change characteristics can provide reference for the practice of mining area reclamation and the improvement of reclamation of the soil quality.In this paper,the reclaimed soil in Tunlan mining area Gujiao City in Shanxi Province,on the west side of Taiyuan fault basin,is taken as the research object.The distribution characters and change regulation of water stable aggregates and organic carbon in reclaimed soil were analyzed by different plant species,different fertilization and reclamation period,and the stability of reclaimed soil structure and the change regulation of soil nutrients was clarified,so as to recover the land in industrial and mining areas reclamation and ecological restoration provide theoretical and technical support.The main conclusions of this paper were as follows:(1)After six years of planting treatments of corn,soybean and hairy vetch,the micro-aggregate in the water stable aggregates of the reclaimed soil was dominant.Compared with no recreation,the proportion of large aggregates(>0.25 mm)in reclaimed soil was increased with different plant planting treatments,and the larger particle size content of micro-aggregates in reclaimed soil was significantly increased in planting treatments with different plant(P<0.05),but the stability of soil aggregates was not significantly different in different plant planting treatments.Under different plant planting treatments,the content of organic carbon in the large aggregates of reclaimed soil(>0.25 mm): corn > soybean > hairy vetch;In terms of the organic carbon content of large aggregates(>0.25 mm),the content of organic carbon in the aggregates of reclaimed soil with a particle size of > 2 mm was the largest compared with other grain sizes.In terms of the organic carbon content of micro-aggregates(<0.25 mm),the content of organic carbon in corn and soybean was larger than that of other micro aggregates in the larger particle size(0.25-0.15 mm).After planting corn,the organic carbon of soil aggregate was larger than that of soybean and hairy vetch,and the fixation effect of corn root was better.(2)In the reclaimed soil,the content of macro-aggregate increased gradually with the extension of planting years of different plants,in which the content of macro-aggregate(>2 mm and 2-1 mm)increased significantly by planting corn,the structural stability of soil macroaggregate was enhanced;The content of macro-aggregate(0.5-0.25 mm)increased significantly,but the structural stability of soil macro-aggregate changed little.The content of macro-aggregate(0.5-0.25 mm)increased significantly by planting soybean and hairy vetch,and the structure of macro-aggregate became more and more stable in the soil with corn planting.The content of the particle size of macro-aggregate(0.25-0.15 mm)increased gradually with the extension of planting years,and the soil micro-aggregate structure became more and more stable with the extension of reclamation years.The organic carbon content of large aggregate(>0.25 mm)in reclaimed soil gradually increased with the years of reclamation.The organic carbon content of small aggregate with large particle size(0.25-0.15 mm)also gradually increased,and the increase range was large,so the contribution rate to the organic carbon of aggregate was large.(3)There were some differences in the content of soil aggregates between the root area and non-root area of corn,soybean and hairy vetch.In the large aggregates(>0.25 mm),the content of soil large aggregates in the root area is lower than that in the non-root area of soybean and hairy vetch,and the content of soil aggregates in the root area of corn is lower than that in the non-root area.In the micro-aggregate(0.25-0.15 mm),the content of micro-aggregate in the root area was higher than that in the non-root area of maize and vetch,and the effect of soybean on the micro-aggregate was more complex.The root of plant obviously promoted the concentration of soil particles with larger diameter(0.25-0.15 mm),so the structure of soil micro-aggregate in plant root area is more stable than that in non root area.(4)After planting corn with different fertilization,the aggregate structure of reclaimed soil treated with organic and inorganic fertilizer was more stable.Compared with no fertilizer application,the content of large aggregate(0.5-0.25 mm)was higher after fertilizer application in reclaimed soil(>0.25mm),and the organic carbon content and the stability of soil aggregate structure could be improved by the combination of organic fertilizer and inorganic fertilizer.In the micro-aggregate(<0.25 mm),the content of micro-aggregate(0.25-0.15 mm)was higher by the combination of organic fertilizer and inorganic fertilizer,and the organic carbon content of soil aggregate was higher,and the structure was more stable.By applying organic and inorganic fertilizers,the contribution rate of soil organic carbon was increased,but the main source of soil organic carbon was micro aggregate.