The landscape of soil carbon data: Emerging questions, synergies and databases

Soil carbon has been measured for over a century in applications ranging from understanding biogeochemical processes in natural ecosystems to quantifying the productivity and health of managed systems. Consolidating diverse soil carbon datasets is increasingly important to maximize their value, particularly with growing anthropogenic and climate change pressures. In this progress report, we describe recent advances in soil carbon data led by the International Soil Carbon Network and other networks. We highlight priority areas of research requiring soil carbon data, including (a) quantifying boreal, arctic and wetland carbon stocks, (b) understanding the timescales of soil carbon persistence using radiocarbon and chronosequence studies, (c) synthesizing long-term and experimental data to inform carbon stock vulnerability to global change, (d) quantifying root influences on soil carbon and (e) identifying gaps in model–data integration. We also describe the landscape of soil datasets currently available, highlighting their strengths, weaknesses and synergies. Now more than ever, integrated soil data are needed to inform climate mitigation, land management and agricultural practices. This report will aid new data users in navigating various soil databases and encourage scientists to make their measurements publicly available and to join forces to find soil-related solutions.

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Greater soil carbon stocks and faster turnover rates with increasing agricultural productivity

SOIL ◽

10.5194/soil-3-1-2017 ◽

2017 ◽

Vol 3 (1) ◽

pp. 1-16 ◽

Cited By ~ 21

Author(s):

Jonathan Sanderman ◽

Courtney Creamer ◽

W. Troy Baisden ◽

Mark Farrell ◽

Stewart Fallon

Keyword(s):

Organic Matter ◽

Soil Carbon ◽

Sugar Content ◽

Bulk Composition ◽

Agricultural Productivity ◽

Carbon Stocks ◽

Decay Rates ◽

Turnover Rates ◽

Soil Carbon Stocks

Abstract. Devising agricultural management schemes that enhance food security and soil carbon levels is a high priority for many nations. However, the coupling between agricultural productivity, soil carbon stocks and organic matter turnover rates is still unclear. Archived soil samples from four decades of a long-term crop rotation trial were analyzed for soil organic matter (SOM) cycling-relevant properties: C and N content, bulk composition by nuclear magnetic resonance (NMR) spectroscopy, amino sugar content, short-term C bioavailability assays, and long-term C turnover rates by modeling the incorporation of the bomb spike in atmospheric 14C into the soil. After > 40 years under consistent management, topsoil carbon stocks ranged from 14 to 33 Mg C ha−1 and were linearly related to the mean productivity of each treatment. Measurements of SOM composition demonstrated increasing amounts of plant- and microbially derived SOM along the productivity gradient. Under two modeling scenarios, radiocarbon data indicated overall SOM turnover time decreased from 40 to 13 years with increasing productivity – twice the rate of decline predicted from simple steady-state models or static three-pool decay rates of measured C pool distributions. Similarly, the half-life of synthetic root exudates decreased from 30.4 to 21.5 h with increasing productivity, indicating accelerated microbial activity. These findings suggest that there is a direct feedback between accelerated biological activity, carbon cycling rates and rates of carbon stabilization with important implications for how SOM dynamics are represented in models.

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Long-term impact of chronosequential land use change on soil carbon stocks on a Swedish farm

Nutrient Cycling in Agroecosystems ◽

10.1007/s10705-007-9156-9 ◽

2007 ◽

Vol 81 (2) ◽

pp. 145-155 ◽

Cited By ~ 27

Author(s):

Thomas Kätterer ◽

Liselotte Andersson ◽

Olof Andrén ◽

Jan Persson

Keyword(s):

Land Use ◽

Land Use Change ◽

Soil Carbon ◽

Carbon Stocks ◽

Soil Carbon Stocks ◽

Long Term Impact

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Modelling soil carbon stocks in semi-natural and agro-ecosystems – quantifying national scale impacts of the Anthropocene

10.5194/egusphere-egu2020-18355 ◽

2020 ◽

Author(s):

Victoria Janes-Bassett ◽

Jessica Davies ◽

Richard Bassett ◽

Dmitry Yumashev ◽

Ed Rowe ◽

...

Keyword(s):

Land Use ◽

Nutrient Cycling ◽

Soil Carbon ◽

Carbon Storage ◽

Management Practices ◽

Carbon Stocks ◽

Soil Carbon Storage ◽

National Scale ◽

Soil Carbon Stocks

Throughout the Anthropocene, the conversion of land to agriculture and atmospheric deposition of nitrogen have resulted in significant changes to biogeochemical cycling, including soil carbon stocks. Quantifying these changes is complex due to a number of influential factors (including climate, land use management, soil type) and their interactions. As the largest terrestrial store of carbon, soils are a key component in climate regulation. In addition, soil carbon storage contributes to numerous ecosystem services including food provision. It is therefore imperative that we understand changes to soil carbon stocks, and provide effective strategies for their future management.Modelling soil systems provides a means to estimate changes to soil carbon stocks. Due to linkages between the carbon cycle and other major nutrient cycles (notably nitrogen and phosphorus which often limit the productivity of ecosystems), models of integrated nutrient cycling are required to understand the response of the carbon cycle to global pressures. Simulating the impacts of land use changes requires capacity to model both semi-natural and intensive agricultural systems.In this study, we have developed an integrated carbon-nitrogen-phosphorus model of semi-natural systems to include representation of both arable and grassland systems, and a range of agricultural management practices. The model is applicable to large spatial scales, as it uses readily available input data and does not require site-specific calibration. &#160;After being validated both spatially and temporally using data from long-term experimental sites across Northern-Europe, the model was applied at a national scale throughout the United Kingdom to assess the impacts of land use change and management practices during the last two centuries. Results indicate a decrease in soil carbon in areas of agricultural expansion, yet in areas of semi-natural land use, atmospheric deposition of nitrogen has resulted in increased net primary productivity and subsequently soil carbon. The results demonstrate anthropogenic impacts on long-term nutrient cycling and soil carbon storage, and the importance of integrated nutrient cycling within models.

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Effects of Temporal Variation in Long-Term Cultivation on Organic Carbon Sequestration in Calcareous Soils: Nile Delta, Egypt

Sustainability ◽

10.3390/su12114514 ◽

2020 ◽

Vol 12 (11) ◽

pp. 4514

Author(s):

Manal Alnaimy ◽

Martina Zelenakova ◽

Zuzana Vranayova ◽

Mohamed Abu-Hashim

Keyword(s):

Carbon Sequestration ◽

Soil Carbon ◽

Nile Delta ◽

Soil Carbon Sequestration ◽

Climate Mitigation ◽

Main Role ◽

Virgin Soil ◽

Logarithmic Curve ◽

Sequestration Potential

Soil carbon sequestration is a riskier long-term strategy for climate mitigation than direct emissions reduction, but it plays a main role in closing carbon emission gaps. Effects of long-term cultivation on soil carbon sequestration were studied at the western edge of the Nile Delta near Alexandria, Egypt. Seven agricultural fields of different ages (0–50 years in use) were selected and compared with the surrounding desert (virgin soil) and desert shrub-land. Samples were taken at three horizons, 0–30, 30–60, and 60–90 cm, and tested for differences in physical and chemical properties. The results of long-term cultivation reveal that the European Commission (EC) value was 11.77 dS/m in virgin soil, while the EC values decreased to 5.82, 4.23, 3.74, 2.40, and 2.26 dS/m after 5, 10, 20, 30, and 50 years of cultivation, respectively. The calcareous rock fraction smaller than 50 μm in size revealed another phenomenon, where active calcium carbonate content increased with cultivation practices from 1.15% (virgin soil) to 5.42%, 6.47%, 8.38%, and 10.13% after 5, 10, 20, and 30 years of cultivation, respectively, while shrub-land also showed a low amount of active CaCO3 with 1.38%. In fifty years of cultivation, soil bulk density decreased significantly from 1.67 to 1.11 g/cm3, and it decreased to 1.65, 1.44, 1.40, and 1.25 g/cm3 after 5, 10, 20, and 30 years, respectively. These results reveal that the increase in soil carbon stock in the upper 90 cm amounted to 41.02 t C/ha after five years of cultivation, compared to virgin soil with 13.47 t C/ha. Soil carbon levels increased steeply during the five years of cultivation, with an average rate of 8.20 t C/ha per year in the upper 90 cm. After the first five years of cultivation, the carbon sequestration rate slowed, reaching 4.68, 3.77, 2.58, and 1.93 t C/ha per year after 10, 20, 30, and 50 years, respectively, resulting in sequestration-potential values of 46.78, 75.63, 77.43, and 96.45 t C/ha. These results indicate that potential soil carbon sequestration resembles a logarithmic curve until the equilibrium state between carbon application and decomposition by microorganisms is reached.

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Does long-term center-pivot irrigation increase soil carbon stocks in semi-arid agro-ecosystems?

Geoderma ◽

10.1016/j.geoderma.2008.03.002 ◽

2008 ◽

Vol 145 (1-2) ◽

pp. 121-129 ◽

Cited By ~ 59

Author(s):

K. Denef ◽

C.E. Stewart ◽

J. Brenner ◽

K. Paustian

Keyword(s):

Soil Carbon ◽

Carbon Stocks ◽

Center Pivot ◽

Soil Carbon Stocks ◽

Semi Arid

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Impact of Sampling Depth on Differences in Soil Carbon Stocks in Long-Term Agroecosystem Experiments

Soil Science Society of America Journal ◽

10.2136/sssaj2010.0099 ◽

2011 ◽

Vol 75 (1) ◽

pp. 226-234 ◽

Cited By ~ 57

Author(s):

A. J. VandenBygaart ◽

E. Bremer ◽

B. G. McConkey ◽

B. H. Ellert ◽

H. H. Janzen ◽

...

Keyword(s):

Soil Carbon ◽

Carbon Stocks ◽

Sampling Depth ◽

Soil Carbon Stocks

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Impacts of nitrogen addition on switchgrass root-associated diazotrophic community structure and function

FEMS Microbiology Ecology ◽

10.1093/femsec/fiaa208 ◽

2020 ◽

Vol 96 (12) ◽

Author(s):

Darian N Smercina ◽

Sarah E Evans ◽

Maren L Friesen ◽

Lisa K Tiemann

Keyword(s):

Community Structure ◽

Panicum Virgatum ◽

Agricultural Practices ◽

Bioenergy Crops ◽

Climate Mitigation ◽

N Addition ◽

Short Term ◽

And Function ◽

Diazotrophic Community

ABSTRACT Cellulosic bioenergy crops, like switchgrass (Panicum virgatum), have potential for growth on lands unsuitable for food production coupled with potential for climate mitigation. Sustainability of these systems lies in identifying conditions that promote high biomass yields on marginal lands under low-input agricultural practices. Associative nitrogen fixation (ANF) is a potentially important nitrogen (N) source for these crops, yet ANF contributions to plant N, especially under fertilizer N addition are unclear. In this study, we assess structure (nifH) and function (ANF) of switchgrass root-associated diazotrophic communities to long-term and short-term N additions using soil from three marginal land sites. ANF rates were variable and often unexpectedly high, sometimes 10× greater than reported in the literature, and did not respond in repeatable ways to long-term or short-term N. We found few impacts of N addition on root-associated diazotrophic community structure or membership. Instead, we found a very consistent root-associated diazotrophic community even though switchgrass seeds were germinated in soil from field sites with distinct diazotrophic communities. Ultimately, this work demonstrates that root-associated diazotrophic communities have the potential to contribute to switchgrass N demands, independent of N addition, and this may be driven by selection of the diazotrophic community by switchgrass roots.

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Energy, water and carbon exchanges in managed forest ecosystems: description, sensitivity analysis and evaluation of the INRAE GO+ model, version 3.0

10.5194/gmd-2020-66 ◽

2020 ◽

Author(s):

Virginie Moreaux ◽

Simon Martel ◽

Alexandre Bosc ◽

Delphine Picart ◽

David Achat ◽

...

Keyword(s):

Soil Carbon ◽

Mechanistic Model ◽

Biogeochemical Processes ◽

Forest Operations ◽

Time Step ◽

Vegetation Control ◽

Clear Cutting ◽

Go Model ◽

The Impact

Abstract. The mechanistic model GO+ describes the functioning and growth of managed forests based upon biophysical and biogeochemical processes. The biophysical and biogeochemical processes included are modelled using standard formulations of radiative transfer, convective heat exchange, evapotranspiration, photosynthesis, respiration, plant phenology, growth and mortality, biomass nutrient content, and soil carbon dynamics. The forest ecosystem is modelled as three layers, namely the tree overstorey, understorey and soil. The vegetation layers include stems, branches and foliage and are partitioned dynamically between sunlit and shaded fractions. The soil carbon sub-model is an adaption of the Roth-C model to simulate the impact of forest operations. The model runs at an hourly time-step. It represents a forest stand covering typically 1 ha and can be straightforwardly up-scaled across gridded data at regional, country or continental levels. GO+ accounts for both the immediate and long-term impacts of forest operations on energy, water and carbon exchanges within the soil-vegetation-atmosphere continuum. It includes exhaustive and versatile descriptions of management operations (soil preparation, regeneration, vegetation control, selective thinning, clear-cutting, coppicing, etc.), thus permitting the effects of a wide variety of forest management strategies to be estimated: from close-to-nature to intensive. This paper examines the sensitivity of the model to its main parameters and estimates how errors in parameter values are propagated into the predicted values of its main output variables. We show how the model performs when compared with observations such as time series of forest-atmosphere exchanges of energy, water and CO2 monitored over Douglas fir, European beech and pine forests of different ages as well as long-term series of tree growth, soil water and soil carbon data recorded at continuously monitored forests plots. We also illustrate the capacity of the GO+ model to simulate the provision of key ecosystem services, such as the long-term storage of carbon in biomass and soil under various management and climate scenarios.

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