Soil Organic Carbon and Carbonates are Binding Phases for Simultaneously Extractable Metals in Calcareous Saltmarsh Soils

2019 ◽  
Vol 38 (12) ◽  
pp. 2688-2697 ◽  
Author(s):  
Elisa Pellegrini ◽  
Marco Contin ◽  
Livia Vittori Antisari ◽  
Chiara Ferronato ◽  
Maria De Nobili
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Extractable Metals

scholarly journals Continental-scale controls on soil organic carbon across sub-Saharan Africa

SOIL ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 305-332
Author(s):  
Sophie F. von Fromm ◽  
Alison M. Hoyt ◽  
Markus Lange ◽  
Gifty E. Acquah ◽  
Ermias Aynekulu ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Land Cover ◽  
Soil Texture ◽  
Sub Saharan Africa ◽  
Continental Scale ◽  
Weathered Soils ◽  
Exchangeable Ca ◽  
Extractable Metals ◽  
Sub Saharan

Abstract. Soil organic carbon (SOC) stabilization and destabilization has been studied intensively. Yet, the factors which control SOC content across scales remain unclear. Earlier studies demonstrated that soil texture and geochemistry strongly affect SOC content. However, those findings primarily rely on data from temperate regions where soil mineralogy, weathering status and climatic conditions generally differ from tropical and subtropical regions. We investigated soil properties and climate variables influencing SOC concentrations across sub-Saharan Africa. A total of 1601 samples were analyzed, collected from two depths (0–20 and 20–50 cm) from 17 countries as part of the Africa Soil Information Service project (AfSIS). The data set spans arid to humid climates and includes soils with a wide range of pH values, weathering status, soil texture, exchangeable cations, extractable metals and land cover types. The most important SOC predictors were identified by linear mixed-effects models, regression trees and random forest models. Our results indicate that geochemical properties, mainly oxalate-extractable metals (Al and Fe) and exchangeable Ca, are equally important compared to climatic variables (mean annual temperature and aridity index). Together, they explain approximately two-thirds of SOC variation across sub-Saharan Africa. Oxalate-extractable metals were most important in wet regions with acidic and highly weathered soils, whereas exchangeable Ca was more important in alkaline and less weathered soils in drier regions. In contrast, land cover and soil texture were not significant SOC predictors on this large scale. Our findings indicate that key factors controlling SOC across sub-Saharan Africa are broadly similar to those in temperate regions, despite differences in soil development history.

Early responses of vegetation and soil organic carbon to waterlogging and winter wildfire on abandoned red paddy soils

2014 ◽  
Vol 38 (6) ◽  
pp. 626-634
Author(s):  
TIAN Wen-Wen ◽  
◽  
WANG Wei ◽  
CHEN An-Lei ◽  
LI Yu-Yuan ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Paddy Soils
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