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Possible Mechanisms Leading to a Delay in Carbon Stock Recovery after Land Use Change
Author(s) -
Arai Hirotsugu,
Tokuchi Naoko,
Koba Keisuke
Publication year - 2007
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2005.0309
Subject(s) - grassland , soil carbon , environmental science , soil horizon , litter , soil science , soil water , fractionation , land use, land use change and forestry , topsoil , land use , agronomy , chemistry , ecology , biology , organic chemistry
Changes in land use sometimes lead to soil C loss, and a long time may be required for the C stock to recover to initial levels. Thus, it is important to evaluate the mechanisms related to accumulation of newly input C following land use changes. In this study, we sought to determine the signature of newly input C in the soil profile after land use change. We used stable and radioactive C isotopes with soil fractionation methods in a C 3 coniferous plantation converted from C 4 grassland in Japan. The difference in δ 13 C values between the surface litter and the soil organic carbon (SOC) below the litter was 5‰ or greater; this large isotopic difference was attributed to rapid decomposition in the litter layer and preservation of C derived from the previous C 4 vegetation. Most SOC Δ 14 C values were negative throughout the soil profile, suggesting that most of the SOC in the soil profile was recalcitrant and had been preserved for a long time. Only the surface sand values were slightly positive. These results suggest that most newly input C is consumed at the soil surface. The low ability of these soils to preserve newly input C is one factor in the slow recovery of soil C.