The Relationship between Soil Particle Size Fractions, Associated Carbon Distribution and Physicochemical Properties of Historical Land-Use Types in Newly Formed Reservoir Buffer Strips

Water impoundment reshapes the ecological environment around the bank-line of newly built reservoirs. Therefore, reservoir buffer strips play a disproportionately large role in the maintenance of ecosystem functions and environmental benefits during the early stage of reservoir formation. However, there are gaps in the research on soil particle-size-associated carbon distribution characteristics within different historical land-use types in newly formed reservoir buffer strips. In this study, we focused on soil particle size fractions, aggregate stability, and particle-size-associated carbon distribution characteristics of different historical land-use types of reservoir buffer strips at distance scale (i.e., different distance from the water) after reservoir impoundment in the Chushandian Reservoir, China, and explored the relationship between them. The results showed that the soil texture of abandoned cropland and grassland are classified as silt loam and woodland are classified as sandy loam; different historical land-use types in newly formed reservoir buffer strips showed significant differences in soil aggregate stability after reservoir impoundment; a distance scale was used to measure these differences, which were mainly due to the dry-wet cycles and water submerged condition caused by the buffers’ different distances from water. The newly formed reservoir buffer strips underwent corresponding changes in the particle-size-associated carbon distribution characteristics after reservoir impoundment, mainly due to the turnover property of different soil particles combined with organic carbon. Reservoir impoundment accelerates the turnover of silt particle and associated nutrients in soils of historical land-use types in newly formed reservoir buffer strips; turnover may be mediated mainly by microbial biomass.