Carbon input threshold for soil carbon budget optimization in eroding vineyards

Abstract. Natural and anthropogenic mercury (Hg) emissions are sequestered in terrestrial soils over short, annual, to long, millennial time scales, before Hg mobilization and run-off impacts wetland and coastal Ocean ecosystems. Recent studies have used Hg to carbon (C) ratios, RHgC, measured in Alaskan permafrost mineral and peat soils, together with a northern soil carbon inventory, to estimate that these soils contain large amounts, 184 to 755 Gg of Hg in the upper 1 m. However, measurements of RHgC on Siberian permafrost peatlands are largely missing, leaving the size of estimated northern soil Hg budget, and its fate under arctic warming scenarios uncertain. Here we present Hg and carbon data for 6 peat cores, down to mineral horizons at 1.5–4 m depth, across a 1700 km latitudinal (56 to 67° N) permafrost gradient in the Western Siberian lowlands (WSL). Hg concentrations increase from south to north in all soil horizons, reflecting enhanced net accumulation of atmospheric gaseous Hg by the vegetation Hg pump. The RHgC in WSL peat horizons decreases with depth from 0.38 Gg Pg−1 in the active layer to 0.23 Gg Pg−1 in continuously frozen peat of the WSL. We estimate the Hg pool (0 1 m) in the permafrost-affected part of WSL peatlands to be 9.3 ± 2.7 Gg. We review and estimate pan-arctic organic and mineral soil RHgC to be 0.19 and 0.77 Gg Pg−1, and use a soil carbon budget to revise the northern soil Hg pool to be 67 Gg (37–88 Gg, interquartile range (IQR)) in the upper 30 cm, 225 Gg (102–320 Gg) in the upper 1 m, and 557 Gg (371–699 Gg) in the upper 3 m. Using the same RHgC approach, we revise the global upper 30 cm soil Hg pool to contain 1078 Gg of Hg (842–1254 Gg, IQR), of which 6 % (67 Gg) resides in northern permafrost soils. Additional soil and river studies must be performed in Eastern and Northern Siberia to lower the uncertainty on these estimates, and assess the timing of Hg release to atmosphere and rivers.

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Assessing the impact of cover crop as a GHG mitigation solution at intra-field scale using the AgriCarbon-EO tool

10.5194/egusphere-egu21-15272 ◽

2021 ◽

Author(s):

Taeken Wijmer ◽

Ahmad Al Bitar ◽

Remy Fieuzal ◽

Ludovic Arnaud ◽

Gaetan Pique ◽

...

Keyword(s):

High Resolution ◽

Soil Carbon ◽

Cover Crops ◽

Cover Crop ◽

Carbon Budget ◽

Carbon Stocks ◽

Optical Data ◽

Agricultural Practice ◽

Soil Carbon Stocks ◽

Sentinel 2

<p>Increasing soil carbon stocks has been identified as a major climate change mitigation solution. As a consequence, an objective of 4/1000 yearly increment in soil carbon stocks has been proposed at the COP21.&#160; Sustainable agriculture provides several solutions to meet this objective and among those solutions, the implementation of cover crops has been identified as most efficient. Currently, a comprehensive modeling tool that takes into account the major bio-geophysical processes with associated uncertainties, while assimilating frequent high-resolution observations at large scale could allow accounting for the effect of cover crops on the carbon budget in a realistic way. In this study, we quantify the components of the carbon budget at high resolution and we analyse the effect of cover crops. Computations are based on the newly developed AgriCarbon-EO tool which assimilates full resolution (10-20m) Sentinel-2 optical data into a radiative transfer model (PROSAIL), and a crop model (SAFYE-CO2). The assimilation scheme is based on a Bayesian approach which provides the retrieved biogeophysical variables with their associated uncertainties. Uncertainties are essential when determining the carbon stocks. For instance, the future European Common Agricultural Practice (CAP) may take into consideration the uncertainty of the determination of the soil carbon stocks changes in the evaluation of the subsidies. The main inputs of the computations are weather data, soil texture maps, crop maps and surface reflectances. The Sentinel-2 Leaf Area Index (LAI) are obtained from those Sentinel-2 surface reflectance by inverting the PROSAIL model. These are then assimilated into the SAFY_CO2 model to determine the carbon budget components. To validate our approach, we implemented the AgriCarbon-EO tool over a set of plots in south-western France over which we dispose of biomass measurements for cover crops in wheat/cover crop/maize rotations for 2017-2018 and 2019-2020 agricultural seasons. Also, the CO2 fluxes are validated against eddy covariance flux measurements in the same context. Our study shows that the cover crops allow on average 250gC/m&#178; of organic carbon with a high spatial heterogeneity. This has important implications regarding the dynamic of carbon storage in agronomic soils and demonstrates the importance of high-resolution agronomic modeling.</p>

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Soil Carbon Dynamics and Carbon Budget of Newly Reconstructed Tall-grass Prairies in South Central Iowa

Journal of Environmental Quality ◽

10.2134/jeq2009.0063 ◽

2010 ◽

Vol 39 (1) ◽

pp. 136-146 ◽

Cited By ~ 31

Author(s):

Jose G. Guzman ◽

Mahdi M. Al-Kaisi

Keyword(s):

Soil Carbon ◽

Carbon Budget ◽

Carbon Dynamics ◽

Tall Grass ◽

Soil Carbon Dynamics ◽

South Central

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Evaluation of the soil carbon budget under different upland cropping systems in central Hokkaido, Japan

Soil Science & Plant Nutrition ◽

10.1111/j.1747-0765.2008.00279.x ◽

2008 ◽

Vol 54 (4) ◽

pp. 650-661 ◽

Cited By ~ 17

Author(s):

Zhijian Mu ◽

Sonoko D. Kimura ◽

Yo Toma ◽

Ryusuke Hatano

Keyword(s):

Soil Carbon ◽

Carbon Budget ◽

Cropping Systems

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Methodology for estimating soil carbon for the forest carbon budget model of the United States, 2001

Environmental Pollution ◽

10.1016/s0269-7491(01)00213-5 ◽

2002 ◽

Vol 116 (3) ◽

pp. 373-380 ◽

Cited By ~ 31

Author(s):

L.S. Heath ◽

R.A. Birdsey ◽

D.W. Williams

Keyword(s):

United States ◽

Soil Carbon ◽

Carbon Budget ◽

The United States ◽

Forest Carbon ◽

Budget Model ◽

Carbon Budget Model

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Inclusion of soil carbon lateral movement alters terrestrial carbon budget in China

Scientific Reports ◽

10.1038/srep07247 ◽

2014 ◽

Vol 4 (1) ◽

Cited By ~ 20

Author(s):

Haicheng Zhang ◽

Shuguang Liu ◽

Wenping Yuan ◽

Wenjie Dong ◽

Aizhong Ye ◽

...

Keyword(s):

Soil Carbon ◽

Carbon Budget ◽

Lateral Movement ◽

Terrestrial Carbon

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Microbial dormancy and its impacts on northern temperate and boreal terrestrial ecosystem carbon budget

Biogeosciences ◽

10.5194/bg-17-4591-2020 ◽

2020 ◽

Vol 17 (18) ◽

pp. 4591-4610

Author(s):

Junrong Zha ◽

Qianla Zhuang

Keyword(s):

Greenhouse Gases ◽

Soil Carbon ◽

Carbon Budget ◽

Terrestrial Ecosystem ◽

Terrestrial Ecosystems ◽

Carbon Dynamics ◽

Earth System ◽

New Model ◽

Ecosystem Carbon ◽

Earth System Models

Abstract. A large amount of soil carbon in northern temperate and boreal regions could be emitted as greenhouse gases in a warming future. However, lacking detailed microbial processes such as microbial dormancy in current biogeochemistry models might have biased the quantification of the regional carbon dynamics. Here the effect of microbial dormancy was incorporated into a biogeochemistry model to improve the quantification for the last century and this century. Compared with the previous model without considering the microbial dormancy, the new model estimated the regional soils stored 75.9 Pg more C in the terrestrial ecosystems during the last century and will store 50.4 and 125.2 Pg more C under the RCP8.5 and RCP2.6 scenarios, respectively, in this century. This study highlights the importance of the representation of microbial dormancy in earth system models to adequately quantify the carbon dynamics in the northern temperate and boreal natural terrestrial ecosystems.

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Crops for Carbon Farming

Frontiers in Plant Science ◽

10.3389/fpls.2021.636709 ◽

2021 ◽

Vol 12 ◽

Author(s):

Christer Jansson ◽

Celia Faiola ◽

Astrid Wingler ◽

Xin-Guang Zhu ◽

Alexandra Kravchenko ◽

...

Keyword(s):

Soil Carbon ◽

Carbon Budget ◽

Carbon Allocation ◽

Cropping Systems ◽

Arable Land ◽

Crop Productivity ◽

Microbial Consortia ◽

Sink Strength ◽

Soil System ◽

Belowground Carbon Allocation

Agricultural cropping systems and pasture comprise one third of the world’s arable land and have the potential to draw down a considerable amount of atmospheric CO2 for storage as soil organic carbon (SOC) and improving the soil carbon budget. An improved soil carbon budget serves the dual purpose of promoting soil health, which supports crop productivity, and constituting a pool from which carbon can be converted to recalcitrant forms for long-term storage as a mitigation measure for global warming. In this perspective, we propose the design of crop ideotypes with the dual functionality of being highly productive for the purposes of food, feed, and fuel, while at the same time being able to facilitate higher contribution to soil carbon and improve the below ground ecology. We advocate a holistic approach of the integrated plant-microbe-soil system and suggest that significant improvements in soil carbon storage can be achieved by a three-pronged approach: (1) design plants with an increased root strength to further allocation of carbon belowground; (2) balance the increase in belowground carbon allocation with increased source strength for enhanced photosynthesis and biomass accumulation; and (3) design soil microbial consortia for increased rhizosphere sink strength and plant growth-promoting (PGP) properties.

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The changing carbon balance of tundra ecosystems: results from a vertically-resolved peatland biosphere model

Environmental Research Letters ◽

10.1088/1748-9326/ac4070 ◽

2021 ◽

Author(s):

Erik Joseph Lester Larson ◽

Luke Schiferl ◽

Roisin Commane ◽

J William Munger ◽

Anna T Trugman ◽

...

Keyword(s):

Soil Carbon ◽

Carbon Budget ◽

Soil Column ◽

Predictive Ability ◽

Heterotrophic Respiration ◽

Sensitivity Analyses ◽

The Arctic ◽

Soil Carbon Stock ◽

Alaskan Tundra ◽

Biosphere Model

Abstract An estimated 1700 Pg of carbon is frozen in the Arctic permafrost and the fate of this carbon is unclear because of the complex interaction of biophysical, ecological and biogeochemical processes that govern the Arctic carbon budget. Two key processes determining the region’s long-term carbon budget are: (i) carbon uptake through increased plant growth, and (ii) carbon release through increased heterotrophic respiration due to warmer soils. Previous predictions for how these two opposing carbon fluxes may change in the future have varied greatly, indicating that improved understanding of these processes and their feedbacks is critical for advancing our predictive ability for the fate of Arctic peatlands. In this study, we implement and analyze a vertically-resolved model of peatland soil carbon into a cohort-based terrestrial biosphere model to improve our understanding of how on-going changes in climate are altering the Arctic carbon budget. A key feature of the formulation is that accumulation of peat within the soil column modifies its texture, hydraulic conductivity, and thermal conductivity, which, in turn influences resulting rates of heterotrophic respiration within the soil column. Analysis of the model at three eddy covariance tower sites in the Alaskan tundra shows that the vertically-resolved soil column formulation accurately captures the zero-curtain phenomenon, in which the temperature of soil layers remain at or near 0 °C during fall freezeback due to the release of latent heat, is critical to capturing observed patterns of wintertime respiration. We find that significant declines in net ecosystem productivity (NEP) occur starting in 2013 and that these declines are driven by increased heterotrophic respiration arising from increased precipitation and warming. Sensitivity analyses indicate that the cumulative NEP over the decade responds strongly to the estimated soil carbon stock and more weakly to vegetation abundance at the beginning of the simulation.

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