To reveal effects of vegetation restoration on soil structure at the molecular scale, three typical vegetation restoration types in degraded red soil were selected which were Pinus massoniana-broadleaved multiple layer forest ( PB ) , Schima superba-Pinus massoniana mixed forest (SP) and broad-leaved forest (BF), respectively.Using field investigations and lab assays to investigate the distribution characteristics and contribution rate of soil water-stable aggregate organic carbon in 0～60 cm soil layers in each of the three types.The results showed that the soil water-stable aggregate content and the contribution rate of the aggregate organic carbon were distributed as"W"or"N"with the reduction of aggregate particle size;particles less than 0.05 mm in diameter made up the majority of water-stable aggregates in soil, and the macro-aggregate content reduced rapidly when water-sieving which suggested that the macro-aggregates were more susceptible to water infiltration; the water-stable aggregate content of particles more than 0.25 mm in upper soil layers (0～40 cm) was the highest in PB while the content in lower soil layer ( 40～60 cm) was relatively close ( 48.80％～51.64％) among three types.The content of soil total organic carbon and water-stable aggregate organic carbon were ranked as PB>SP>BF exhibiting reductions with the increase of soil depth; the organic carbon contents of macro water-stable aggregates were higher than those of micro water-stable aggregates (<0.25 mm in diameter ) suggesting that organic carbon may play an active role in the formation and the water-stability of macro aggregates.The contribution rate of soil aggregate organic carbon of particle in 0.05～0.25 mm was minimum in all the three types, and the contribution rate of soil aggregate organic carbon of particle more than 2.00 mm in PB was significantly higher than that in SP and BF ( P<0.05) .PB had the highest macro water-stable aggregates and aggregate organic carbon content among the three types which can be attributed to the high density and coverage of understory shrubs/herbs in PB, and it was more conducive to the improvement of the soil structure and function.
国家科技期刊平台
NSTL
万方数据
维普
