When does organic carbon induce aggregate stability in vertosols?

Smith, Rhiannon; Tongway, David J.; Tighe, Matthew; Reid, Nick

doi:10.1016/j.agee.2014.12.002

Cited by 26 publications

(14 citation statements)

References 44 publications

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“…Crop residue application caused SOC increase in various aggregate fractions. Macroaggregates (>2000 mm and 2000-250 mm) showed the highest carbon sequestration capacity, in consistent with previous studies, which demonstrated that macroaggregates contain more SOC than microaggregates (Cambardella and Elliot, 1993;Puget et al, 1995;Ashagrie et al, 2007;Choudhury et al, 2014;Smith et al, 2015). According to Tisdall and Oades (1982), microaggregates and silt/clay are bound together by organic compounds of different origin (including coarse organic matter derived from crop residue) to form macroaggregates (Simonetti et al, 2012).…”

Section: Aggregate Restructuring and Soc Stabilitysupporting

confidence: 90%

Isotopic characterization of sequestration and transformation of plant residue carbon in relation to soil aggregation dynamics

Guan

Dou

Chen

et al. 2015

Applied Soil Ecology

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Section: Aggregate Restructuring and Soc Stabilitysupporting

confidence: 90%

Isotopic characterization of sequestration and transformation of plant residue carbon in relation to soil aggregation dynamics

Guan

Dou

Chen

et al. 2015

Applied Soil Ecology

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“…And it had a stronger correlation with MWD (r 2 = 0.90) than soil moisture (r 2 = 0.79) ( Fig 1 ), suggesting that soil aggregation may provide a degree of physical protection, and thus serve to prevent the decomposition of SOC. The positive correlation between bulk SOC and MWD was also reported by Smith, Tongway [ 24 ]. Previous studies have revealed that SOC decomposition rate in forest soils increased in the order: macroaggregates < microaggregates < silt and clay-sized complexes [ 5 , 25 , 26 ].…”

Section: Discussionsupporting

confidence: 77%

Association of Soil Aggregation with the Distribution and Quality of Organic Carbon in Soil along an Elevation Gradient on Wuyi Mountain in China

Vogel

et al. 2016

PLoS ONE

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Forest soils play a critical role in the sequestration of atmospheric CO2 and subsequent attenuation of global warming. The nature and properties of organic matter in soils have an influence on the sequestration of carbon. In this study, soils were collected from representative forestlands, including a subtropical evergreen broad-leaved forest (EBF), a coniferous forest (CF), a subalpine dwarf forest (DF), and alpine meadow (AM) along an elevation gradient on Wuyi Mountain, which is located in a subtropical area of southeastern China. These soil samples were analyzed in the laboratory to examine the distribution and speciation of organic carbon (OC) within different size fractions of water-stable soil aggregates, and subsequently to determine effects on carbon sequestration. Soil aggregation rate increased with increasing elevation. Soil aggregation rate, rather than soil temperature, moisture or clay content, showed the strongest correlation with OC in bulk soil, indicating soil structure was the critical factor in carbon sequestration of Wuyi Mountain. The content of coarse particulate organic matter fraction, rather than the silt and clay particles, represented OC stock in bulk soil and different soil aggregate fractions. With increasing soil aggregation rate, more carbon was accumulated within the macroaggregates, particularly within the coarse particulate organic matter fraction (250–2000 μm), rather than within the microaggregates (53–250μm) or silt and clay particles (< 53μm). In consideration of the high instability of macroaggregates and the liability of SOC within them, further research is needed to verify whether highly-aggregated soils at higher altitudes are more likely to lose SOC under warmer conditions.

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“…Piccolo & Mbagwu () found that organic waste addition in soils induced aggregation effects on sand‐size aggregates and soil microaggregate stability was significantly correlated with humic substances content. Smith et al () observed that microaggregate stability was attributed to the dominance of Ca 2+ over Na + on clay exchange sites and organic matter may play a role in microaggregate stabilization through its capacity to lower soil pH and increase the availability of Ca 2+ .…”

Section: Resultsmentioning

confidence: 99%

Vermicompost and Gypsum Amendments Improve Aggregate Formation in Bauxite Residue

et al. 2017

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Improving aggregate formation and stability of bauxite residue is essential for the development of a soil on the residue. Effects of gypsum and vermicompost on related chemical and physical conditions of bauxite residue were studied in a laboratory incubation experiment. The addition of gypsum at 2% and 4% w/w reduced pH and exchangeable sodium percentage while increasing exchangeable calcium content. The addition of vermicompost reduced bulk density while significantly increasing porosity and total organic carbon. Vermicompost had a positive effect on the formation and stabilization of water‐stable aggregates in the residue, while gypsum was more beneficial to silt‐sized microaggregate flocculation. Amendments also enhanced the erosion resistance of bauxite residue. Furthermore, wet sieving using the modified Le Bissonnais' method revealed that in comparison with differential clay swelling and mechanical breakdown, slaking was the major disaggregation mechanism of residue aggregates. The combination of gypsum and vermicompost converted the residue from a sheet‐like structure to a granular macroaggregated structure while converting microaggregates from a grain to a granular or prismatic structure. The findings of this work suggest that application of gypsum and vermicompost to bauxite residue may directly influence aggregate size distribution and its micromorphology, resulting in the improvement of both aggregate stability and structure. Copyright © 2017 John Wiley & Sons, Ltd.

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When does organic carbon induce aggregate stability in vertosols?

Cited by 26 publications

References 44 publications

Isotopic characterization of sequestration and transformation of plant residue carbon in relation to soil aggregation dynamics

Isotopic characterization of sequestration and transformation of plant residue carbon in relation to soil aggregation dynamics

Association of Soil Aggregation with the Distribution and Quality of Organic Carbon in Soil along an Elevation Gradient on Wuyi Mountain in China

Vermicompost and Gypsum Amendments Improve Aggregate Formation in Bauxite Residue

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