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- Li, Xiaojuan, et al.
(author)
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Climate and soil properties drive soil organic and inorganic carbon patterns across a latitudinal gradient in southwestern China
- 2023
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In: Journal of Soils and Sediments. - : Springer Science and Business Media LLC. - 1614-7480 .- 1439-0108. ; 23:1, s. 91-102
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Journal article (peer-reviewed)abstract
- PurposeDrylands account for 47.2% of land area and contain 15.5% of global carbon (C). However, the variation in organic and inorganic C stocks across latitudinal gradients in arid and semiarid shrubland ecosystems remains understudied, and we lack in-depth understanding of the main drivers of C variation at this spatial scale.MethodsHere, we sampled soils from 95 sites across a latitudinal gradient to explore both the latitudinal patterns and potential drivers of soil organic carbon density (SOCD) and soil inorganic carbon density (SICD). We also assessed variation in SOCD and SICD down the soil profile, by sampling soils at four depths (0 – 10 cm, 10 – 20 cm, 20 – 30 cm, and 30 – 50 cm).ResultBoth SOCD and SICD exhibited a binomial relationship with latitude (P < 0.01). Soil properties accounted for the greatest variation in SOCD, with the most important explanatory factor being exchangeable calcium, followed by mean annual temperature, pH, plant diversity, and silt content. Soil pH and plant diversity were more important in explaining variation in SOCD in the subsoil (> 20 cm depth) than the topsoil. For SICD, soil properties explained the greatest variation at all depths. Soil pH explained the most variance in SICD, followed by exchangeable calcium and mean annual temperature in the topsoil (i.e., 0 – 10 cm and 10 – 20 cm). In the subsoil (i.e., 20 – 30 cm and 30 – 50 cm), exchangeable calcium was the most important predictor, followed by soil organic carbon, mean annual temperature, and pH.ConclusionOur study shows that soil properties are a strong predictor of latitudinal patterns of soil organic and inorganic C in arid and semiarid shrubland ecosystems. We also identified differences in potential drivers of SOCD and SICD with depth, advancing our understanding of large-scale patterns of C storage in arid and semiarid soils.
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| 2. |
- Li, Xiaojuan, et al.
(author)
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Latitudinal patterns of light and heavy organic matter fractions in arid and semi-arid soils
- 2022
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In: Catena. - : Elsevier BV. - 0341-8162. ; 215
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Journal article (peer-reviewed)abstract
- Semi-arid and arid ecosystems are important for the global C cycle. Despite this, it remains unclear how organic matter fractions vary across latitudinal gradients, and what drives this variation, in dry ecosystems. In this study, we sampled soils from 100 sites across a latitudinal gradient in the dry valleys of southwestern China to explore the latitudinal patterns of light fraction organic matter (LFOM) and heavy fraction organic matter (HFOM) at two soil depths (0–10 cm and 10–20 cm). Across the studied gradient, HFOM accounted for a larger fraction of soil organic matter than LFOM. LFOM increased exponentially with increasing latitude at both 0–10 cm and 10–20 cm depths. Heavy fraction organic C increased linearly with increasing latitude at both depths, while heavy fraction organic N only increased with latitude in soils from 10 to 20 cm depth. Latitudinal patterns of LFOM were mainly explained by climate, with the most important driver being mean annual temperature, followed by mean annual precipitation. Soil physicochemical factors – in particular cation exchange capacity and silt content – explained the most variation in HFOM. Total microbial biomass was also important in explaining variation in HFOM, especially in the 10–20 cm soil layer. Overall, our results shed light on the spatial distribution of organic matter fractions in arid and semi-arid regions. We also identify candidate drivers of the variation in LFOM and HFOM in arid and semi-arid regions, finding that climate primarily explains variation in LFOM while soil physiochemistry primarily explains variation in HFOM.
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