Soil soluble carbon dynamics of manured and unmanured grasslands following chemical kill and ploughing

MacDonald, J. D.; Chantigny, Martin H.; Angers, Denis A.; Rochette, Philippe; Royer, Isabelle; Gasser, Marc‐Olivier

doi:10.1016/j.geoderma.2011.05.011

“…Consistent with this paradigm all of our soils released more C during the anoxic incubations than at similar pH in oxic incubations (p b 0.01; Table 2). In addition, our incubations release six to over 400 times as much carbon during anoxic incubation than previously published work (Fiedler and Kalbitz, 2003;Grybos et al, 2009;Hagedorn et al, 2000;Jacinthe et al, 2003;MacDonald et al, 2011). The high amounts of C mobilization in our study likely reflect the substantial (8-32%) C content of the horizons we studied, although C content does not explain the slightly lower dispersion of C in the Pu'u Eke (350 ky) soil relative to the other soils (Tables 1 and 2).…”

Section: Carbon Mobilization During Fe Reductioncontrasting

confidence: 42%

“…Our work suggests that nanoparticulate and colloidal C are important contributors to mobile organic carbon (MOC), which have been overlooked in previous studies that lump DOC as any C that passes through 200 nm (e.g., Grybos et al, 2009), 450 nm (e.g., Fiedler and Kalbitz, 2003;Hagedorn et al, 2000;MacDonald et al, 2011), or even micron sized filters (e.g., Jacinthe et al, 2003). In fact, the large majority of MOC released in our anoxic experiment was colloidal (b430 nm) or nano-particulate C (2.3-60 nm) rather than soluble C (b10,000 Da) (Figs.…”

Section: Carbon Mobilization During Fe Reductionmentioning

confidence: 89%

“…The onset of anoxic conditions in organic-rich soil horizons commonly triggers an increase in soil solution C (Fiedler and Kalbitz, 2003;Grybos et al, 2009;Hagedorn et al, 2000;Jacinthe et al, 2003;Kogel-Knabner et al, 2010;MacDonald et al, 2011). While lower C mineralization rates via anaerobic vs. aerobic metabolism may play a role (Fiedler and Kalbitz, 2003;Kalbitz et al, 2000;Moore and Dalva, 2001), most studies ascribe this increase in DOC to reductiondriven loss of Fe-(oxyhydr)oxide surface area for C sorption (e.g., Kogel-Knabner et al, 2010).…”

Section: Carbon Mobilization During Fe Reductionmentioning

confidence: 99%

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Depth and character of rock weathering across a basaltic‐hosted climosequence on Hawai‘i

Goodfellow

¹

,

Chadwick

²

,

Hilley

³

2013

Earth Surf Processes Landf

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. The transport of organic carbon (C) to deep mineral horizons in soils can lead to long-term C stabilization. In basaltic soils, C associations with short-range-ordered (SRO) minerals often lead to colloid-sized aggregates that can be dispersed and mobilized by changes in soil solution chemistry. In the montane forest region of Hawaii, basaltic soils are exposed to high rainfall and anoxic conditions that facilitate ferric (Fe III ) (oxyhydr)oxide reduction. We explored the potential of iron (Fe)-reducing conditions to mobilize C by exposing the surface mineral horizons of three soils from the Island of Hawai'i (aged 0.3, 20, and 350 ky) to 21 days of anoxic incubation in 1:10 soil slurries. Mobilized C was quantified by fractionating the slurries into three particle-size classes (b430 nm,b 60 nm,b2.3 nm ≈ 10 kDa). In all three soils, we found Fe reduction (maximum Fe 2+ (aq) concentration ≈ 17.7 ± 1.9 mmol kg −1 soil) resulted iñ 500% and~700% increase of C in the 2.3-430 nm, and b 2.3 nm size fractions, respectively. In addition, Fe reduction increased solution ionic strength by 127 μS cm −1 and generated hydroxyl ions sufficient to increase the slurry pH by one unit. We compared this to C mobilized from the slurries during a 2-h oxic incubation across a similar range of pH and ionic strength and found smaller amounts of dissolved (b 2.3 nm) and colloidal (2.3-430 nm) C were mobilized relative to the Fe reduction treatments (p b 0.05). In particular, C associated with the largest particles (60-430 nm) was dispersed almost exclusively during the Fe reduction experiments, suggesting that it had been bound to Feoxide phases. Our experiments suggest that colloidal dispersion during Fe-reducing conditions mobilizes high concentrations of C, which may explain how C migrates to deep mineral horizons in redox dynamic soils.

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“…This makes grassland renovation, even in its extreme form of ploughing and reseeding, different from the transformation to arable land where the soil will be regularly disturbed by tillage, and large quantities of C and N will inevitably be lost over a long period of time that can actually last decades (Davies, Smith, & Vinten, ; Springob, ). Immediate large N leaching losses and emissions of C and other greenhouse gases are almost unavoidable when grassland is turned to arable cropping (Curtin, Fraser, & Beare, ; Kayser, Seidel, Müller, & Isselstein, ; MacDonald, Chantigny et al., ; Poeplau et al., ; Velthof et al., ).…”

Section: Renovation and Related Yields And C Fluxesmentioning

confidence: 99%

“…However, there is still a lack of systematic research on the topic. Nutrient emissions occur as gaseous losses and leaching (MacDonald, Chantigny et al., ). Emissions of CO 2 are related to soil mineralization (Willems et al., ), and N 2 O mainly to enhanced N turnover and fertilization (Merbold et al., ) with the additional risk of indirect N 2 O emissions that are related to larger NO 3 leaching losses (Davies et al., ; Krol et al., ; MacDonald, Rochette et al., ).…”

Section: Renovation and Emission Risksmentioning

confidence: 99%

Grassland renovation has important consequences for C and N cycling and losses

Kayser

¹

,

Müller

²

,

Isselstein

³

2018

Food and Energy Security

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Sward degradation is a serious threat to the functioning of agricultural grassland and the provision of ecosystem services. Renovation measures are frequently applied to restore degraded swards. The success is highly variable, and substantial trade-offs can be related to the process of renovation. This paper starts with a general classification of renovation measures and then investigates the processes that are directly related to renovation and lead to a change in botanical composition and affect soil functions and C and N fluxes. These processes are strongly interrelated and dependent on site, climate, and management condition as well as on the timescale. The more an existing and degraded sward is deliberately disturbed prior to a renovation measure, for example, by ploughing, the stronger will be the change in sward composition, and the stronger will be the potential yield and quality advantage. However, the risk of a release of soil organic C and N emissions to the environment will also increase. These emissions will usually decrease in time, but so will the positive effects on sward composition. This demonstrates that the renovation of swards is normally the second best solution and a proper and well-adapted grassland utilization and management should be adopted to avoid degradation in the first place. K E Y W O R D Scarbon, nitrogen, reseeding, sward improvement, vegetation

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Mobilization of colloidal carbon during iron reduction in basaltic soils

Buettner

¹

,

Kramer

²

,

Chadwick

³

et al. 2014

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. The transport of organic carbon (C) to deep mineral horizons in soils can lead to long-term C stabilization. In basaltic soils, C associations with short-range-ordered (SRO) minerals often lead to colloid-sized aggregates that can be dispersed and mobilized by changes in soil solution chemistry. In the montane forest region of Hawaii, basaltic soils are exposed to high rainfall and anoxic conditions that facilitate ferric (Fe III ) (oxyhydr)oxide reduction. We explored the potential of iron (Fe)-reducing conditions to mobilize C by exposing the surface mineral horizons of three soils from the Island of Hawai'i (aged 0.3, 20, and 350 ky) to 21 days of anoxic incubation in 1:10 soil slurries. Mobilized C was quantified by fractionating the slurries into three particle-size classes (b430 nm,b 60 nm,b2.3 nm ≈ 10 kDa). In all three soils, we found Fe reduction (maximum Fe 2+ (aq) concentration ≈ 17.7 ± 1.9 mmol kg −1 soil) resulted iñ 500% and~700% increase of C in the 2.3-430 nm, and b 2.3 nm size fractions, respectively. In addition, Fe reduction increased solution ionic strength by 127 μS cm −1 and generated hydroxyl ions sufficient to increase the slurry pH by one unit. We compared this to C mobilized from the slurries during a 2-h oxic incubation across a similar range of pH and ionic strength and found smaller amounts of dissolved (b 2.3 nm) and colloidal (2.3-430 nm) C were mobilized relative to the Fe reduction treatments (p b 0.05). In particular, C associated with the largest particles (60-430 nm) was dispersed almost exclusively during the Fe reduction experiments, suggesting that it had been bound to Feoxide phases. Our experiments suggest that colloidal dispersion during Fe-reducing conditions mobilizes high concentrations of C, which may explain how C migrates to deep mineral horizons in redox dynamic soils.

show abstract

Soil soluble carbon dynamics of manured and unmanured grasslands following chemical kill and ploughing

Cited by 10 publications

References 40 publications

Depth and character of rock weathering across a basaltic‐hosted climosequence on Hawai‘i

Depth and character of rock weathering across a basaltic‐hosted climosequence on Hawai‘i

Grassland renovation has important consequences for C and N cycling and losses

Mobilization of colloidal carbon during iron reduction in basaltic soils

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