Akademik Veri Yönetim Sistemi
JOURNAL OF SOIL SCIENCE AND PLANT NUTRITION, cilt.24, sa.3, ss.5029-5042, 2024 (SCI-Expanded, Scopus)
The purpose of this study was to evaluate the responses of carbon (C) and nitrogen (N) in dry and wet sieved aggregates or particles to the litter treatment and N addition, in a forest ecosystem, assuming that the dynamic changes of bulk soil C and N dependent on soil structure and soil fractions. Soil in an evergreen broad-leaf forest (Castanopsis faberi, Hance) has undergone 8 years of N deposition, such as control (CT), low N (LN) and high N (HN), treated as 0, 30 and 100 kg N ha(- 1) yr(- 1) for first three years, and 0, 75 and 150 kg N ha(- 1) yr(- 1) for last five years, respectively. Concurrently, other treatments were considered as litter removal and litter remaining. Soils were collected and separated first by dry sieving (> 2000 mu m, 250-2000 mu m, 53-250 mu m, < 53 mu m). Then the dry sieved large aggregates (> 2000 mu m or 250-2000 mu m) were dispersed and separated by wet sieving as the six sizes (> 2000 mu m, 250-2000 mu m, 53-250 mu m, < 53 mu m, 20-53 mu m, < 20 mu m). Soil C and N in these soil fractions were investigated. The results revealed that soil aggregates (> 2000 mu m, 250-2000 mu m, 53-250 mu m, < 53 mu m) exhibited higher C and N concentrations in smaller particles when dry sieved. However, the C and N concentrations were lower in smaller particles after the wet sieving of the previously dry-sieved aggregates. Specifically, C and N concentrations in 53-250 mu m and < 53 mu m dry-sieved aggregates surpassed those of the same particle size in the wet-sieving. Overall, both litter and N additions elevated C and N concentrations across all fractions. The presence of litter particularly increased C and N concentrations for soil fractions smaller than 2000 mu m, but the extent varied based on the specific size. After dry sieving, the N addition led to more increase in C and N concentrations as aggregate size decreased, especially in the < 53 mu m aggregates under high N treatment. Conversely, following wet sieving, N addition resulted in less increase in C and N concentrations as aggregate size decreased. For dry-sieved aggregates, the increase in C and N concentrations due to low N addition in the presence of litter was more on average than that in the absence of litter, and this increase in wet-sieved aggregates due to N addition was inverse. Notably, in the absence of litter, N addition did not induce a decline in C and N. Both the presence of litter and N addition most significantly increased C and N in the 20-53 mu m fraction among the wet-sieved soil fractions. The decomposition of litter contributes to C and N in soil aggregates > 250 mu m and < 250 mu m as different forms, in which water might play an important role for aggregation and C and N storage. Under presence of litter, N deposition is beneficial for improving soil C and N.