Soil Aggregate Composition And Carbon Stability In Two Vegetation Restoration Modes

Vegetation restoration was one of important pathways to improve soil quality in degradation hilly red soil. With the rise and development of underground-ecology, soil aggregate composition, nutrient content and organic carbon stability and its inherent relevance has been a hot topics and scientific frontier in ecology research. But vegetation restoration how to influence soil physical structure, chemical properties, stability of organic carbon and the coupling mechanism between different variables was still unclear. This article has selected two typical vegetation restoration pattern as subjects to discuss the effect of vegetation recovery mode on soil aggregate composition, soil nutrient and the stability of organic carbon to provide a reference for evaluation the effect of vegetation restoration in hilly red soil region. The main results were as follows:(1) Percentage of>5mm soil aggregate was highest,1-2mm soil aggregate had the lowest percentage accounting both in the two vegetation restoration model.>5mm and2-5mm soil aggregate content in Pinus massoniana forest were lower than Liquidambar formosana forest.>5mm and0.25-0.5mm soil aggregate content were characterized by upper slope<middle slope<downhill,1-2mm for hill soil aggregate performance> middle slope> down slope,1-2mm soil aggregate content of upper position was higher than other slope, while the ratio of the other soil aggregate in middle slope were greater than that in uphill and downhill.(2) Organic carbon, total nitrogen and total phosphorus content were generally characterized by upper position<middle slope<downhill and surface soil>middle layer>deep soil. Vegetation restoration mode effected soil aggregate nutrient significantly and soil organic carbon, total nitrogen and total phosphorus content in masson pine forest were lower than liquidambar. Organic carbon and nitrogen content in0.25-1mm soil aggregate was significantly higher than others.(3) Soil aggregate carbon release rate were characterized by surface layer> deep soil, downhill>middle and upper slope and1-2mm and0.25mm soil aggregate were higher than others. In the whole process, carbon mineralization rate showed a slow- fast-slow trend with the extension of incubation time.1-2mm and<0.25mm soil aggregate organic mineralization were higher than others in two vegetation restoration mode.In conclusion, improving soil quality and carbon intercept ability of liquidambar forest was better than masson pine forest because of the difference among aboveground biomass, litter quality and root traits in two forests.