What do relationships between extractable metals and soil organic carbon concentrations mean?

2021 ◽  
Author(s):  
Steven J. Hall ◽  
Aaron Thompson
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Extractable Metals ◽  
Carbon Concentrations

Predicting soil organic carbon concentrations in a low relief landscape, eastern Iran

2018 ◽  
Vol 15 ◽  
pp. e00195 ◽  
Author(s):  
Mohammad Reza Pahlavan-Rad ◽  
Khodadad Dahmardeh ◽  
Colby Brungard
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Eastern Iran ◽  
Carbon Concentrations

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

Should we manage soil organic carbon in Vertosols in the northern grains region of Australia?

2003 ◽  
Vol 43 (3) ◽  
pp. 261 ◽  
Author(s):  
R. J. Farquharson ◽  
G. D. Schwenke ◽  
J. D. Mullen
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
New South ◽  
New South Wales ◽  
Soil Health ◽  
Organic Carbon Content ◽  
Continuous Cropping ◽  
South Wales ◽  
On Farm ◽  
Carbon Concentrations

Two issues prompted this paper. The first was the measured soil organic carbon decline in fertile northern Australian soils under continual cropping using traditional management practices. We wanted to see whether it was theoretically possible to maintain or improve soil organic carbon concentrations with modern management recommendations. The second was the debate about use of sustainability indicators for on-farm management, so we looked at soil organic carbon as a potential indicator of soil health and investigated whether it was useful in making on-farm crop decisions. The analytical results indicated first that theoretically the observed decline in soil organic carbon concentrations in some northern cracking clay soils can be halted and reversed under continuous cropping sequences by using best practice management. Second, the results and associated discussion give some support to the use of soil organic carbon as a sustainability indicator for soil health. There was a consistent correlation between crop input decisions (fertilisation, stubble management, tillage), outputs (yield and profits) and outcomes (change in soil organic carbon content) in the short and longer term. And this relationship depended to some extent on whether the existing soil organic carbon status was low, medium or high. A stock dynamics relationship is one where the change in a stock (such as soil organic carbon) through time is related not only to the management decisions made and other random influences (such as climatic effects), but also to the concentration or level of the stock itself in a previous time period. Against such a requirement, soil organic carbon was found to be a reasonable measure. However, the inaccuracy in measuring soil organic carbon in the paddock mitigates the potential benefit shown in this analysis of using soil organic carbon as a sustainability indicator.These results are based on a simulation model (APSIM) calibrated for a cracking clay (Vertosol) soil typical of much of the intensively-cropped slopes and plains region of northern New South Wales and southern Queensland, and need to be interpreted in this light. There are large areas of such soils in north-western New South Wales; however, many of these experience lower rainfalls and plant-available soil water capacities than in this case, and the importance of these characteristics must also be considered.

scholarly journals Soil organic carbon concentrations and storage in irrigated cotton cropping systems sown on permanent beds in a Vertosol with restricted subsoil drainage

2013 ◽  
Vol 64 (8) ◽  
pp. 799 ◽  
Author(s):  
N. R. Hulugalle ◽  
T. B. Weaver ◽  
L. A. Finlay ◽  
V. Heimoana
Keyword(s):  
Carbon Sequestration ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Management Practices ◽  
Cropping Systems ◽  
Carbon Dynamics ◽  
Wheat Stubble ◽  
Soil Organic Carbon Dynamics ◽  
Carbon Concentrations

Long-term studies of soil organic carbon dynamics in two- and three-crop rotations in irrigated cotton (Gossypium hirsutum L.) based cropping systems under varying stubble management practices in Australian Vertosols are relatively few. Our objective was to quantify soil organic carbon dynamics during a 9-year period in four irrigated, cotton-based cropping systems sown on permanent beds in a Vertosol with restricted subsoil drainage near Narrabri in north-western New South Wales, Australia. The experimental treatments were: cotton–cotton (CC); cotton–vetch (Vicia villosa Roth. in 2002–06, Vicia benghalensis L. in 2007–11) (CV); cotton–wheat (Triticum aestivum L.), where wheat stubble was incorporated (CW); and cotton–wheat–vetch, where wheat stubble was retained as in-situ mulch (CWV). Vetch was terminated during or just before flowering by a combination of mowing and contact herbicides, and the residues were retained as in situ mulch. Estimates of carbon sequestered by above- and below-ground biomass inputs were in the order CWV >> CW = CV > CC. Carbon concentrations in the 0–1.2 m depth and carbon storage in the 0–0.3 and 0–1.2 m depths were similar among all cropping systems. Net carbon sequestration rates did not differ among cropping systems and did not change significantly with time in the 0–0.3 m depth, but net losses occurred in the 0–1.2 m depth. The discrepancy between measured and estimated values of sequestered carbon suggests that either the value of 5% used to estimate carbon sequestration from biomass inputs was an overestimate for this site, or post-sequestration losses may have been high. The latter has not been investigated in Australian Vertosols. Future research efforts should identify the cause and quantify the magnitude of these losses of organic carbon from soil.

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.

Long-term S-fertilization increases carbon sequestration in a sulfur-deficient soil

2014 ◽  
Vol 94 (3) ◽  
pp. 295-301 ◽  
Author(s):  
Mekonnen Giweta ◽  
Miles F. Dyck ◽  
Sukhdev S. Malhi ◽  
Dick Puurveen ◽  
J. A. Robertson
Keyword(s):  
Carbon Sequestration ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Relative Effect ◽  
University Of Alberta ◽  
Rotation System ◽  
The University ◽  
Carbon Concentrations ◽  
Annual Application

Giweta, M., Dyck, M. F., Malhi, S. S., Puurveen, D. and Robertson, J. A. 2014. Long-term S-fertilization increases carbon sequestration in a sulfur-deficient soil. Can. J. Soil Sci. 94: 295–301. We analyzed the change in total soil organic carbon (SOC) in a long-term fertilization experiment (1980–2008) in a wheat–oat–barley–hay–hay rotation system at the University of Alberta Breton Classical plots. Soil samples were taken in 1980, 1990, 1998, 2003 and 2008 from plots that were fertilized with NPKS and NPK. The objective was to compare the relative effect of S fertilization on the SOC stocks in a S-deficient soil. Long-term S fertilization resulted in an increasing trend in soil organic carbon concentrations over 28 yr when N, P and K supply were adequate. The change in SOC with time was significantly different (P<0.05) between the two treatments. Annual application of NPK in combination with S resulted in an increased accumulation of SOC at a rate of 0.11 Mg C ha−1 yr−1 in the 0- to 15-cm depth over NPK alone. Our results suggest that long-term S fertilization in an S-deficient soil helped to sequester C in the soil.

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