Managing Soil Organic Carbon for Mitigating Climate Change and Increasing Food Security

This Special Issue contains articles presenting advances in soil organic carbon (SOC) sequestration practices, considering their benefits, trade-offs and monitoring. The studies deal with (1) agricultural practices and climate change, (2) the effect of organic matter amendments, and (3) the development of monitoring, reporting and verification (MRV) strategies. It is concluded that region-specific approaches are required for the implementation and monitoring of SOC sequestering practices.

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Restoration of degraded grasslands, but not invasion by Prosopis juliflora, avoids trade-offs between climate change mitigation and other ecosystem services

Scientific Reports ◽

10.1038/s41598-020-77126-7 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Purity Rima Mbaabu ◽

Daniel Olago ◽

Maina Gichaba ◽

Sandra Eckert ◽

René Eschen ◽

...

Keyword(s):

Climate Change ◽

Ecosystem Services ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Climate Change Mitigation ◽

Arid Regions ◽

Prosopis Juliflora ◽

Trade Offs ◽

Change Mitigation ◽

Semi Arid

AbstractGrassland degradation and the concomitant loss of soil organic carbon is widespread in tropical arid and semi-arid regions of the world. Afforestation of degraded grassland, sometimes by using invasive alien trees, has been put forward as a legitimate climate change mitigation strategy. However, even in cases where tree encroachment of degraded grasslands leads to increased soil organic carbon, it may come at a high cost since the restoration of grassland-characteristic biodiversity and ecosystem services will be blocked. We assessed how invasion by Prosopis juliflora and restoration of degraded grasslands in a semi-arid region in Baringo, Kenya affected soil organic carbon, biodiversity and fodder availability. Thirty years of grassland restoration replenished soil organic carbon to 1 m depth at a rate of 1.4% per year and restored herbaceous biomass to levels of pristine grasslands, while plant biodiversity remained low. Invasion of degraded grasslands by P. juliflora increased soil organic carbon primarily in the upper 30 cm and suppressed herbaceous vegetation. We argue that, in contrast to encroachment by invasive alien trees, restoration of grasslands in tropical semi-arid regions can both serve as a measure for climate change mitigation and help restore key ecosystem services important for pastoralists and agro-pastoralist communities.

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How much should we increase carbon inputs to the soil to reach a 4per1000 objective of soil organic carbon storage in European agricultural sites: a multi-modelling approach

10.5194/egusphere-egu21-1666 ◽

2021 ◽

Author(s):

Elisa Bruni

Keyword(s):

Climate Change ◽

Organic Matter ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Anthropogenic Emissions ◽

Climate Mitigation ◽

Experimental Conditions ◽

Interesting Approach ◽

Soc Stocks ◽

Modelling Approach

Anthropogenic greenhouse gases emissions are the main driving force of climate change. They need to be strongly reduced during the next Century until carbon neutrality in order to keep the international 2&#176;C objective of the Paris Agreement on Climate. The &#8220;4per1000&#8221; initiative was launched in 2015 as a climate mitigation option, with an aspiration to increase global soil organic carbon (SOC) stocks by 4&#8240; per year to compensate for the anthropogenic emissions of carbon dioxide in the atmosphere. The &#8220;4per1000&#8221; is not applicable everywhere, hence a full compensation of anthropogenic emissions is unlikely. Nevertheless, where possible, it has been identified as an interesting approach to mitigate climate change and, at the same time, ensure food security through improved soil fertilization. To reach such an objective one must either reduce carbon outputs (e.g. erosion and respiration) or increase the inputs of biomass to the soil.Here, we use a multi-modelling approach to study the challenges of SOC storage potential through increased organic inputs in agricultural sites. The aim is to respond to the following question: &#8220;What is the amount of carbon inputs that needs to be brought to soils as a means to increase SOC stocks by 4&#8240; per year?&#8221; This scientific question belongs to the family of inverse problems and is addressed by using a multi-modelling approach, to improve the predictions and associated uncertainties of model outputs.The amount of required carbon inputs to reach the 4per1000 is estimated over 30 years of simulations with five different models (Century, RothC, ICBM, AMG and Millennial) and is compared to more than 15 long-term arable experiments of organic matter addition in Europe. This allows estimating the feasibility of a 4per1000 objective in temperate, north-temperate and Mediterranean regions with different treatments of organic matter inputs. As a final step, we evaluate the sensitivity of the predicted carbon inputs requirement to future projections of climate change.The 4per1000 initiative is an interesting approach to contribute for the mitigation of climate change through agriculture. Here, we will present preliminary results of a multi-modelling analysis showing that the necessary inputs to reach the 4per1000 target are realistic for some experimental conditions, but might be too high to be implemented at a larger scale.

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Managing Soil Organic Carbon for Climate Change Mitigation and Food Security

10.1201/9781003243090-2 ◽

2021 ◽

pp. 25-46

Author(s):

You Jin Kim ◽

Ji Young Jung ◽

Umakant Mishra

Keyword(s):

Climate Change ◽

Food Security ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Climate Change Mitigation ◽

Change Mitigation

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Modelling dynamic interactions between soil structure and the storage and turnover of soil organic matter

Biogeosciences ◽

10.5194/bg-17-5025-2020 ◽

2020 ◽

Vol 17 (20) ◽

pp. 5025-5042

Author(s):

Katharina Hildegard Elisabeth Meurer ◽

Claire Chenu ◽

Elsa Coucheney ◽

Anke Marianne Herrmann ◽

Thomas Keller ◽

...

Keyword(s):

Climate Change ◽

Organic Matter ◽

Soil Organic Matter ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Bulk Density ◽

Green Manure ◽

Water Retention ◽

Model Parameters ◽

Soil Water Retention

Abstract. Models of soil organic carbon (SOC) storage and turnover can be useful tools to analyse the effects of soil and crop management practices and climate change on soil organic carbon stocks. The aggregated structure of soil is known to protect SOC from decomposition and, thus, influence the potential for long-term sequestration. In turn, the turnover and storage of SOC affects soil aggregation, physical and hydraulic properties and the productive capacity of soil. These two-way interactions have not yet been explicitly considered in modelling approaches. In this study, we present and describe a new model of the dynamic feedbacks between soil organic matter (SOM) storage and soil physical properties (porosity, pore size distribution, bulk density and layer thickness). A sensitivity analysis was first performed to understand the behaviour of the model. The identifiability of model parameters was then investigated by calibrating the model against a synthetic data set. This analysis revealed that it would not be possible to unequivocally estimate all of the model parameters from the kind of data usually available in field trials. Based on this information, the model was tested against measurements of bulk density, SOC concentration and limited data on soil water retention and soil surface elevation made during 63 years in a field trial located near Uppsala (Sweden) in three treatments with different organic matter (OM) inputs (bare fallow, animal and green manure). The model was able to accurately reproduce the changes in SOC, soil bulk density and surface elevation observed in the field as well as soil water retention curves measured at the end of the experimental period in 2019 in two of the treatments. Treatment-specific variations in SOC dynamics caused by differences in OM input quality could be simulated very well by modifying the value for the OM retention coefficient ε (0.37 for animal manure and 0.14 for green manure). The model approach presented here may prove useful for management purposes, for example, in an analysis of carbon sequestration or soil degradation under land use and climate change.

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Additional carbon inputs to reach a 4 per 1000 objective in Europe: feasibility and projected impacts of climate change based on Century simulations of long-term arable experiments

10.5194/bg-2020-489 ◽

2021 ◽

Author(s):

Elisa Bruni ◽

Bertrand Guenet ◽

Yuanyuan Huang ◽

Hugues Clivot ◽

Iñigo Virto ◽

...

Keyword(s):

Climate Change ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Temperature Increase ◽

Agricultural Practices ◽

Carbon Stocks ◽

Soil Organic Carbon Stocks ◽

Annual Carbon ◽

Soc Stocks

Abstract. The 4 per 1000 initiative aims to promote better agricultural practices to maintain and increase soil organic carbon stocks for soil fertility, food security and climate change adaptation and mitigation. The most straightforward way to enhance soil organic carbon stocks is to increase carbon inputs to the soil. In this study, we assessed the amount of organic carbon inputs that are necessary to reach a target of soil organic carbon stocks increase by 4 ‰ per year on average, for 30 years. We used the Century model to simulate soil organic carbon stocks in 14 European long-term agricultural experiments and assessed the required level of carbon inputs increase to reach the 4 per 1000 target. Initial simulated stocks were computed analytically assuming steady state. We compared modelled carbon inputs to different treatments of additional carbon used on the experimental sites (exogenous organic matter addition and one treatment with different crop rotations). We then analyzed how this would change under future scenarios of temperature increase. The model was calibrated to fit the control plot, i.e. conventional management without additional carbon inputs, and was able to reproduce the SOC stocks dynamics. We found that, on average among the selected experimental sites, annual carbon inputs will have to increase by 43.15 ± 5.05 %, which is 0.66 ± 0.23 MgC ha−1 per year (mean ± standard error), with respect to the control situation. The simulated amount of carbon inputs required to reach the 4 ‰ SOC increase was lower or similar to the amount of carbon inputs actually used in the majority of the additional carbon input treatments of the long-term experiments. However, Century might be overestimating the effect of additional C inputs on the variation of SOC stocks in some sites, since we found that treatments with additional carbon inputs were increasing by 0.25 % on average among the experimental sites. We showed that the modeled carbon inputs required to reach the target depended linearly on the initial SOC stocks. We estimated that annual carbon inputs would have to increase further due to temperature increase effect on decomposition rates, that is 54 % for a 1 °C warming and 120 % for a 5 °C warming.

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Dynamics of soil organic carbon in the steppes of Russia and Kazakhstan under past and future climate and land use

Regional Environmental Change ◽

10.1007/s10113-021-01799-7 ◽

2021 ◽

Vol 21 (3) ◽

Author(s):

Susanne Rolinski ◽

Alexander V. Prishchepov ◽

Georg Guggenberger ◽

Norbert Bischoff ◽

Irina Kurganova ◽

...

Keyword(s):

Climate Change ◽

Land Use ◽

Organic Carbon ◽

Land Use Change ◽

Soil Organic Carbon ◽

Arable Land ◽

Future Climate ◽

Future Climate Change ◽

Climate Scenarios ◽

The Impact

AbstractChanges in land use and climate are the main drivers of change in soil organic matter contents. We investigated the impact of the largest policy-induced land conversion to arable land, the Virgin Lands Campaign (VLC), from 1954 to 1963, of the massive cropland abandonment after 1990 and of climate change on soil organic carbon (SOC) stocks in steppes of Russia and Kazakhstan. We simulated carbon budgets from the pre-VLC period (1900) until 2100 using a dynamic vegetation model to assess the impacts of observed land-use change as well as future climate and land-use change scenarios. The simulations suggest for the entire VLC region (266 million hectares) that the historic cropland expansion resulted in emissions of 1.6⋅ 1015 g (= 1.6 Pg) carbon between 1950 and 1965 compared to 0.6 Pg in a scenario without the expansion. From 1990 to 2100, climate change alone is projected to cause emissions of about 1.8 (± 1.1) Pg carbon. Hypothetical recultivation of the cropland that has been abandoned after the fall of the Soviet Union until 2050 may cause emissions of 3.5 (± 0.9) Pg carbon until 2100, whereas the abandonment of all cropland until 2050 would lead to sequestration of 1.8 (± 1.2) Pg carbon. For the climate scenarios based on SRES (Special Report on Emission Scenarios) emission pathways, SOC declined only moderately for constant land use but substantially with further cropland expansion. The variation of SOC in response to the climate scenarios was smaller than that in response to the land-use scenarios. This suggests that the effects of land-use change on SOC dynamics may become as relevant as those of future climate change in the Eurasian steppes.

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Soil organic carbon monitoring to assess agricultural climate change adaptation practices in Navarre, Spain

Regional Environmental Change ◽

10.1007/s10113-021-01788-w ◽

2021 ◽

Vol 21 (3) ◽

Author(s):

Rodrigo Antón ◽

Francisco Javier Arricibita ◽

Alberto Ruiz-Sagaseta ◽

Alberto Enrique ◽

Isabel de Soto ◽

...

Keyword(s):

Climate Change ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Climate Change Adaptation ◽

Adaptation Practices

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Soil organic carbon storage by shaded and unshaded coffee systems and its implications for climate change mitigation in China

The Journal of Agricultural Science ◽

10.1017/s002185962100006x ◽

2021 ◽

pp. 1-8

Author(s):

Ziwei Xiao ◽

Xuehui Bai ◽

Mingzhu Zhao ◽

Kai Luo ◽

Hua Zhou ◽

...

Keyword(s):

Climate Change ◽

Linear Regression ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Multiple Linear Regression ◽

Carbon Storage ◽

Soil Ph ◽

Soil Bulk Density ◽

Soil N ◽

And Storage

Abstract Shaded coffee systems can mitigate climate change by fixation of atmospheric carbon dioxide (CO2) in soil. Understanding soil organic carbon (SOC) storage and the factors influencing SOC in coffee plantations are necessary for the development of sound land management practices to prevent land degradation and minimize SOC losses. This study was conducted in the main coffee-growing regions of Yunnan; SOC concentrations and storage of shaded and unshaded coffee systems were assessed in the top 40 cm of soil. Relationships between SOC concentration and factors affecting SOC were analysed using multiple linear regression based on the forward and backward stepwise regression method. Factors analysed were soil bulk density (ρb), soil pH, total nitrogen of soil (N), mean annual temperature (MAT), mean annual moisture (MAM), mean annual precipitation (MAP) and elevations (E). Akaike's information criterion (AIC), coefficient of determination (R2), root mean square error (RMSE) and residual sum of squares (RSS) were used to describe the accuracy of multiple linear regression models. Results showed that mean SOC concentration and storage decreased significantly with depth under unshaded coffee systems. Mean SOC concentration and storage were higher in shaded than unshaded coffee systems at 20–40 cm depth. The correlations between SOC concentration and ρb, pH and N were significant. Evidence from the multiple linear regression model showed that soil bulk density (ρb), soil pH, total nitrogen of soil (N) and climatic variables had the greatest impact on soil carbon storage in the coffee system.

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Impact of soil use on aggregate stability and its relationship with soil organic carbon at two different altitudes in the Colombian Andes

Agronomía Colombiana ◽

10.15446/agron.colomb.v37n3.77601 ◽

2019 ◽

Vol 37 (3) ◽

pp. 263-273

Author(s):

Efraín Francisco Visconti-Moreno ◽

Ibonne Geaneth Valenzuela-Balcázar

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Aggregate Stability ◽

Tropical Climate ◽

Mineral Particle ◽

Organic Carbon Content ◽

Rice Soils ◽

Organic Matter Pool ◽

Different Altitudes

The stability of soil aggregates depends on the organic matter, and the soil use and management can affect the soil organicmatter (SOM) content. Therefore, it is necessary to know therelationship between aggregate stability and the content of SOMin different types of soil use at two different altitudes of theColombian Andes. This study examined the conditions of soilaggregate stability expressed as a distribution of the size classes of stable aggregates (SA) and of the mean weighted diameter of the stable aggregates (MWD). To correlate these characteristics with the soil organic carbon (OC), we measured the particulate organic matter pool (POC), the OC associated with the mineral organic matter pool (HOC), the total organic carbon content (TOC), and the humification rate (HR). Soils were sampled at two altitudes: 1) Humic Dystrudepts in a cold tropical climate (CC) with three plots: tropical mountain rainforest, pastures, and crops; 2) Fluvaquentic Dystrudepts in a warm tropical climate (WC) with three plots: tropical rainforest, an association of oil palm and pastures, and irrigated rice. Soils were sampled at three depths: 0-5, 5-10 and 10-20 cm. The physical properties, mineral particle size distribution, and bulk density were measured. The content of SA with size>2.36 mm was higher in the CC soil (51.48%) than in the WC soil (9.23%). The SA with size 1.18-2.36 mm was also higher in the CC soil (7.78%) than in the WC soil (0.62%). The SA with size 0.60-1.18 mm resulted indifferent. The SA with size between 0.30 and 0.60 mm were higher in the WC soil (13.95%) than in the CC soil (4.67%). The SA<0.30 mm was higher in the WC soil (72.56%) than in the CC soil (32.15%). It was observed that MWD and the SA>2.36 mm increased linearly with a higher POC, but decreased linearly with a higher HR. For the SA<0.30 mm, a linear decrease was observed at a higher POC, while it increased at a higher HR.

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