Pioneering assessment of carbon stocks in polder soils developed in inter-dune landscapes in a semiarid climate,Lake Chad     

Abgassi A. Adoum  Patricia Moulin  Michel Brossard 《Comptes Rendus Geoscience》2017,349(1):22-31

In semiarid Sahelian region, the dynamics of soil organic carbon (SOC) and water are key to sustainable land management. This work focuses on the behaviour of carbon. A total of 33 soil profiles in four polders, ranging from 10 to 65 years in age, were sampled, analysed (0–1 m), and matched with marsh soil profiles in recent sediments considered as reference (t₀) for carbon stocks determination. SOC and soil inorganic carbon (SIC) stocks show a spatial variability between polders. SOC stocks were t₀ 200 ± 0.8; t₆₀ 183 ± 34; and t₆₅ 189 ± 1.1 MgC·ha^?1, whereas the SIC stocks were negligible. These results show the highest stocks of soil carbon observed for this climatic region. The SOC stocks were also calculated for the equivalent soil mass at a defined depth (0–0.3 m); the corrected calculation of SOC stocks (S_corr) for 2450 Mg·ha^?1 of equivalent soil mass is t₀ 64 ± 1.9, t₆₀ 59 ± 9.8, and t₆₅ 53 ± 2.2 MgC·ha^?1; the stocks decrease by ?7.8% and ?17.2% from t₀ to t₆₀ and t₆₅. Carbon was inherited from the pre-existing·marsh and the polders have conserved high stock values.  相似文献   

Selenium and heavy metals content in some Mediterranean soils   总被引：1，自引：0，他引：1  

L. Roca-Perez  C. Gil  M.L. Cervera  A. Gonzálvez  J. Ramos-Miras  V. Pons  J. Bech  R. Boluda 《Journal of Geochemical Exploration》2010

The study of metal contents in industrial, agricultural or/and polluted soils compared with natural or unpolluted soils is currently necessary to obtain reference values and to assess soil contamination. Nonetheless, very few works published appear in international journals on elements like Se, Li and Sr in Spanish soils. This study determines the total levels of Se, Li, Sr, As, Cd, Co, Cr, Cu, Ni, Pb, V, Zn, Fe, Mn and Ba in 14 natural (unpolluted) soils (Gypsisols, Leptosols, Arenosols and Acrisols), 14 agricultural soils (Anthrosols, Fluvisols and Luvisols), and 4 industrial–urban affected-surface soil horizons (Anthrosols and Fluvisols) of Eastern Spain. The geochemical baseline concentrations (GBC) and reference values (RV) have been established, and the relationships among elements and also between soil properties and elemental concentrations have been analysed. The RV obtained in this study were (mg kg⁻¹): Se 2.68, Li 115, Sr 298, Cd 0.97, Co 35, Cr 217, Cu 46, Ni 50, Pb 137, V 120, Zn 246, Fe 124,472, Mn 2691, and Ba 743. The RV for Se and Li were used as a preliminary approach to assess soil contamination in Spanish soils. The results confirm human impact on Sr, As, Cd, Cr, Cu, Ni, Pb and Zn soil concentrations, but evidence no deviation from natural Se, Li, Co, V, Fe, Mn and Ba concentrations. The results obtained from the statistical analysis reveal significant correlations between some elements and clay and soil organic matter (SOM) contents, indicating that metal concentrations are controlled by soil composition. One particularly interesting finding is the high correlation coefficients obtained between SOM and Se, Cd, Cr, V, Fe, and Mn, and between clay and Cd, Zn, V, Fe and Mn. Once again, these facts confirm the role of SOM and clay minerals in soil functions and that soil is an ecosystem element responsible for maintaining environmental quality.  相似文献