Characterization of soil organic matter and black carbon in dry tropical forests of Costa Rica

Lorenz, Klaus; Lal, Rattan; Jiménez, Juan J.

doi:10.1016/j.geoderma.2010.05.011

Cited by 17 publications

(9 citation statements)

References 55 publications

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“…The accumulation of alkyl-C was mainly attributable to polymethylene, which comes from the stubble's aerobic decomposition (Lorenz et al, 2010), and NT was the only tillage system that did not disturb the soils in our study. This is consistent with the finding of Schnitzer et al (2006) and Ding et al (2002).…”

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confidence: 55%

Tillage impacts on the fractions and compositions of soil organic carbon

Zhao

Wang

et al. 2012

Geoderma

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This study aimed to reveal the impacts of tillage systems on the fractions (active, slow, and passive carbon) and chemical compositions of soil organic carbon (SOC). A long-term (26 years) tillage experiment in northeast China examined no-tillage (NT), plowing tillage (PT) and deep loosing (DL). The soil samples (from a depth of 0-20 cm) were wet-sieved into five aggregate classes (1000-2000 μm, 500-1000 μm, 250-500 μm, 50-250 μm, and b50 μm). The active carbon (C) and passive C were detected in the 500-1000 μm, 250-500 μm, and 50-250 μm aggregates, and the chemical compositions of SOC in micro-aggregates (b 250 μm) and macro-aggregates (>250 μm) were assessed by CPMAS 13 C NMR. Macro-aggregates contained more SOC concentration than micro-aggregates. However, PT resulted in a greater SOC concentration in 50-500 μm aggregates. NT and DL increased the active C and decreased the slow C in 500-1000 μm aggregates, whereas PT showed the inverse. The 13 C NMR spectrum demonstrated that NT increased alkyl-C content, PT obtained a higher carbonyl-C concentration, and DL gained a greater O-alkyl-C concentration. Moreover, evaluating the impacts of tillage systems on the complexity revealed that the most complicated structure was presented in NT, the least in PT, whereas DL had an intermediate effect. Active C contains C2-C6 carbohydrate and anomeric C (C1) polysaccharides, slow C consists of aldehyde-C, ketonic-C and quinone-C, and the passive C is enriched in aromatic-C. In conclusion, long-term tillage systems significantly affected the fractions and compositions of SOC, with NT stabilizing the SOC.

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confidence: 55%

Tillage impacts on the fractions and compositions of soil organic carbon

Zhao

Wang

et al. 2012

Geoderma

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“…Therefore, a significant part of fire-derived C lasts for long periods of time (e.g., centuries or millennial) and contributes to soil C sequestration (Mastrolonardo et al, 2013;Bod ı et al, 2014;Singh et al, 2014). In tropical forests, frequent wildfires can promote SOM chemical recalcitrance (Rumpel et al, 2007) and, as a consequence, the enrichment of pyrogenic C and the loss of more thermolabile organic compounds, such as carbohydrates (Lorenz et al, 2010;Potes et al, 2012). In this work, we define chemical recalcitrance as an inherent chemical property of a molecule rendering it resistant to decomposition (see Kleber et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Variations in soil carbon sequestration and their determinants along a precipitation gradient in seasonally dry tropical forest ecosystems

Campo

Merino

2016

Global Change Biology

109

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The effect of precipitation regime on the C cycle of tropical forests is poorly understood, despite the existence of models that suggest a drier climate may substantially alter the source-sink function of these ecosystems. Along a precipitation regime gradient containing 12 mature seasonally dry tropical forests growing under otherwise similar conditions (similar annual temperature, rainfall seasonality, and geological substrate), we analyzed the influence of variation in annual precipitation (1240 to 642 mm) and duration of seasonal drought on soil C. We investigated litterfall, decomposition in the forest floor, and C storage in the mineral soil, and analyzed the dependence of these processes and pools on precipitation. Litterfall decreased slightly - about 10% - from stands with 1240 mm yr(-1) to those with 642 mm yr(-1), while the decomposition decreased by 56%. Reduced precipitation strongly affected C storage and basal respiration in the mineral soil. Higher soil C storage at the drier sites was also related to the higher chemical recalcitrance of litter (fine roots and forest floor) and the presence of charcoal across sites, suggesting an important indirect influence of climate on C sequestration. Basal respiration was controlled by the amount of recalcitrant organic matter in the mineral soil. We conclude that in these forest ecosystems, the long-term consequences of decreased precipitation would be an increase in organic layer and mineral soil C storage, mainly due to lower decomposition and higher chemical recalcitrance of organic matter, resulting from changes in litter composition and, likely also, wildfire patterns. This could turn these seasonally dry tropical forests into significant soil C sinks under the predicted longer drought periods if primary productivity is maintained.

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“…This result indicated that ET treatment led to higher decomposition of humin as compared to CK. In general, the increment of alkyl-C during decomposition was mainly attributable to the accumulation of polymethylene during the original plant materials' aerobic decomposition [41].…”

Section: Response Of Humin To Climate Changementioning

confidence: 99%