Soil Organic Carbon: Relating the Walkley-Black Wet Oxidation Method to Loss on Ignition and Clay Content

Forest soils supporting Sal-Shorea robusta (Roxb. ex Gaertn. f.) plantations in the foot hills of Darjeeling and Kurseong Divisions in West Bengal were studied for their physicochemical characteristics and carbon sequestration potential. Soils are acidic, high in organic carbon and clay content but low in soil reaction (pH) and bulk density (BD). Thick deposit of leaf litter and its decomposition products increase the soil organic carbon (SOC). Significant amount of clay content also increases the moisture content which helps in decomposing the organic matter, reducing the bulk density of soil and reduces erosion. Soil organic matter tends to concentrate with roughly more than half of the soil organic carbon in the upper soil horizons (0-30cm) at all the study sites. Among the study sites, Samardanga block registers lowest SOC while Bamanpukuri block shows highest SOC stock.

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Spatial covariation of soil organic carbon, clay content, and drainage class at a regional scale

Landscape Ecology ◽

10.1007/bf00130212 ◽

1995 ◽

Vol 10 (6) ◽

pp. 349-362 ◽

Cited By ~ 33

Author(s):

Eric A. Davidson

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Regional Scale ◽

Clay Content ◽

Drainage Class

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Measuring soil organic carbon: which technique and where to from here?

Soil Research ◽

10.1071/sr14339 ◽

2015 ◽

Vol 53 (7) ◽

pp. 717 ◽

Cited By ~ 7

Author(s):

Timothy J. Johns ◽

Michael J. Angove ◽

Sabine Wilkens

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Time Budget ◽

Analytical Techniques ◽

Wet Oxidation ◽

Spectroscopic Techniques ◽

Research Needs ◽

Important Health ◽

Definition Of ◽

Selection Of

This review compares and contrasts analytical techniques for the measurement of total soil organic carbon (TOC). Soil TOC is seen to be a highly important health and quality indicator for soils, as well as having the potential to sequester atmospheric carbon. Definition of the form of organic carbon measured by a given method is vital to the selection of appropriate methodology, as well as the understanding of what exactly is being measured. Historically, studies of TOC have ranged from basic measures, such as colour and gravimetric analyses, to dry and wet oxidation techniques. In more recent times, various spectroscopic techniques and the application of remote or mobile approaches have gained prominence. The different techniques, even the oldest ones, may have their place in current research depending on research needs, the available time, budget and access to wider resources. This review provides an overview of the various methods, highlights advantages, limitations and research opportunities and provides an indication of what the method actually measures so that meaningful comparisons can be made.

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Geochemical Characteristics of Rare Earth Elements in Soils from Puding Karst Critical Zone Observatory, Southwest China

Sustainability ◽

10.3390/su11184963 ◽

2019 ◽

Vol 11 (18) ◽

pp. 4963 ◽

Cited By ~ 7

Author(s):

Qian Zhang ◽

Guilin Han ◽

Man Liu ◽

Lingqing Wang

Keyword(s):

Rare Earth ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Rare Earth Elements ◽

Southwest China ◽

Clay Content ◽

Critical Zone ◽

Fe Content ◽

Local Soil ◽

Critical Zone Observatory

Soil samples from eight soil profiles under different land-use types were collected at the Puding Karst Critical Zone Observatory, Southwest China, to investigate the distribution, fractionation, and controlling factors of rare earth elements (REEs). The total REEs contents in topsoil ranged from 149.97 to 247.74 mg kg−1, the contents in most topsoil were higher than local soil background value (202.60 mg kg−1), and the highest content was observed in topsoil under cropland. The REEs contents in surface soils from lower slopes sites were higher than that of middle and upper slope sites, and the highest contents were observed in cropland. The PAAS-normalized REEs pattern in soils showed MREEs significantly enriched relative to LREEs and HREEs, and HREEs were enriched relative to LREEs. The results showed that clay content, pH, soil organic carbon, total phosphorus, and Fe content were the main factors influencing the distribution of REEs in karst soils, and soil organic carbon (SOC), Fe content showed better linear relationship with REEs.

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