Vertical variations of soil carbon under different land uses in a karst critical zone observatory (CZO), SW China
نویسندگان
چکیده
Soil is a key carbon reservoir balancing global budget and regulating climate change. Barren soils in karst zones have weak capacity for soil water conservation are readily erodible, making the biogeochemical processes within potentially rapid complex. To explore vertical variation of under conditions its response to land-use change, this study investigated concentrations isotopic compositions both organic inorganic (SOC SIC) different depths four types typical region, SW China. Results show that as depth increases, SOC decrease, δ13C ratios (from −27.3‰ −19.4‰) increase 0–20 cm but decrease at below 20 cm. The fresh mostly sequestered cycled topsoil subject controls than subsoil. turnover rate does not directly co-vary with fractionation among land uses. Long-term cultivation causes loss from soils, which can be alleviated or even partially restored after farming cessation. By contrast, SIC represents < 10% total carbon. heterogeneity direct influence biological factors on weaker relative SOC. low −20.4‰ −3.0‰) indicate there intense dissolution reprecipitation pedogenic carbonate soil, especially upper cultivated layers. These results highlight labile susceptible change zones, need considered estimating sink role variable temporal scales.
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ژورنال
عنوان ژورنال: Geoderma
سال: 2022
ISSN: ['0016-7061', '1872-6259']
DOI: https://doi.org/10.1016/j.geoderma.2022.115741