Factors controlling SOC stability in colluvial soils under contrasting climate and soil weathering conditions
(2022) European Journal of Soil Science — Vol. 73, n° 5, p. 16 (2022)
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Quijano Gaudes, Laura 
- Abstract
- Although agricultural colluvial soils are important storage for soil organic car-bon (SOC), the mechanisms underlying colluvial (cumulative soils) SOC stabilityhave received little attention so far. In this study, we aim to understand to whatextent the main controls on colluvial SOC stability differ from those observed innon-colluvial soils. Paired soil profiles (non-colluvial versus colluvial) were col-lected from five sites which differ in climate, soil geochemical background andcultivation history. Topsoil (0–10 cm) and subsoil (30–50 cm) were analysed forSOC fractions, mineral composition, potential soil respiration and radiocarboncontent. Our analysis showed that for non-colluvial soils, climate, cultivation his-tory and weathering degree have significant effects on potential soil respiration.In contrast, for colluvial soils, the most influential factor for potential soil respi-ration was the rate of accretion and this was independent of climatic and geo-chemical context. Furthermore, accretion rates indirectly affected potential soilrespiration by interacting with the degree of weathering of deposited soil. Thischanged the mineral matrix of colluvial soil settings and thereby may enhancesoil mineral-related SOC stabilisation mechanisms. Together, these results sug-gest that the dominant controls on SOC stability in colluvial soils differ fromthose in non-colluvial soils, and the soil accretion rate is the most important con-trol on colluvial SOC stability in agricultural systems
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Zhao, P., Doetterl, S., Wang, Z., Hoyt, A. M., Wang, E., Yu, H., Quijano Gaudes, L., Fallu, D. J., Brown, A. G., Six, J., & Van Oost, K. (2022). Factors controlling SOC stability in colluvial soils under contrasting climate and soil weathering conditions. European Journal of Soil Science, 73(5), 16. https://doi.org/10.1111/ejss.13311 (Original work published 2022)