Soil organic carbon stability in European mountain meadows

2020 ◽  
Author(s):  
Pablo Raguet ◽  
Pierre Barré ◽  
François Baudin ◽  
Norine Khedim ◽  
Jérôme Poulenard ◽  
...  
Keyword(s):  
Climate Change ◽  
Thermal Analysis ◽  
Organic Carbon ◽  
Plant Communities ◽  
European Mountain ◽  
High Lability ◽  
Mountain Meadows ◽  
Rock Eval ◽  
Lower Plant ◽  
Soc Stocks

<p><span>Soil organic carbon (SOC) stocks play a significant role in global climate regulation. CO</span><sub><span>2</span></sub><span> fluxes between soils and atmosphere partly depend on soil organic matter (SOM) biogeochemical stability. Cold ecosystems are generally characterized by a high SOC stock, a large part of it being stabilized by environmental conditions (</span><span><em>e.g.</em></span><span> low pH and temperature). SOC stocks of cold ecosystems are also supposed to be highly vulnerable to climate change that is cancelling the stabilizing effect of low temperature on SOM.</span></p><p> </p><p><span>The aim of this study was to investigate the biogeochemical characteristics of SOM in mountain meadows at the European scale. Our goal was also to determine how environmental factors, including climate, elevation and plant functional traits could drive SOM stability and chemistry. To do so, we used the soil sample set of the ODYSSEE project (</span><span></span><span>), collected in 65 sites located in the main European’s mountains range (Alps, Pyrenees, Carpathians, Balkans). Topsoils (0–10 cm) from two plant communities (when both were present) were sampled in acidic meadows: </span><span><em>Nardetum strictae</em></span><span> and </span><span><em>Caricetum curvulae</em></span><span>. To assess SOM chemistry and biogeochemical stability, we used several indices based on Rock-Eval® 6 thermal analysis.</span></p><p> </p><p><span>The topsoil samples showed a high concentration of organic carbon (114 ± 54 gC/kg of soil), and a weakly decomposed SOM as indicated by a relatively high C:N ratio (15 ± 2.5), hydrogen content (Rock-Eval® hydrogen index = 358 ± 44 mgHC/gC) and a relatively low oxygen content (Rock-Eval® OI</span><sub><span>RE6</span></sub><span> = 151 ± 10 mgO</span><sub><span>2</span></sub><span>/gC). The decomposition state of SOM increased with mean air temperature in winter. The size of the thermally labile SOC pool was high for all samples (pyrolysable SOC = 27 to 44% of total SOC), and it strongly increased with elevation. The size of the labile SOC pool (pyrolysable SOC) was also negatively correlated to a plant functional trait: the mean height of the plant community. </span></p><p> </p><p><span>The topsoils of European mountains meadows have a high SOC content characterized by a globally high lability that further increases with elevation. The high lability of SOM revealed by Rock-Eval® 6 thermal analysis indicates a generally high vulnerability of SOC to climate change throughout European mountain meadows ecosystems.</span></p><p><span>The grass adaptative strategy developed under a cold climate induces lower plant height and higher carbon allocation to the root system. Higher carbon input to soil and/or allelopathic mechanisms protecting SOM from decomposition could possibly explain that lower plant communities of European acidic alpine meadows are characterized by a more labile SOM.</span></p>

Influences of repeated application of organic waste products on soil organic carbon content and stability assessed using Rock-Eval 6® thermal analysis

2020 ◽  
Author(s):  
Amicie Delahaie ◽  
Pierre Barré ◽  
Lauric Cécillon ◽  
François Baudin ◽  
Camille Resseguier ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Organic Waste ◽  
Waste Products ◽  
Clear Effect ◽  
Wide Range ◽  
Rock Eval ◽  
The Impact

<p>The term Organic Waste Products (OWPs) encompasses a wide range of byproducts such as manure, sewage sludge or green waste compost. The use of OWPs impacts soil quality and functioning, agricultural yields, carbon (C) sequestration, biogeochemical cycles of nutrients like nitrogen (N) or phosphorus, and organic matter (OM) dynamics. These impacts likely depend on the considered OWP.</p><p>Taking advantage of 3 mid to long-term experimental trials (6 to 20 years) located in the Northern part of France (Paris region; Brittany; Alsace), we investigated the impact of 16 different OWPs on C content and stability. To do so, surface soil samples from replicated plots amended with the different OWPs used either alone or in addition with mineral N fertilization and appropriated control treatments were analyzed using Rock-Eval 6® thermal analyses. Samples taken up at the onset of the experiment and after 6, 18 and 20 years for the 3 sites respectively were analyzed. It resulted in the analyses of 248 different samples whose Rock-Eval 6® (RE6) signature can be used as a proxy for soil organic carbon (SOC) biogeochemical stability. In particular, we determined 2 RE6 parameters that were related to SOC biogeochemical stability in previous studies (e.g. Barré et al., 2016): HI (the amount of hydrogen-rich effluents formed during the pyrolysis phase of RE6; mgCH.g<sup>-1</sup> SOC), and T50 CO<sub>2</sub> oxidation (the temperature at which 50% of the residual organic C was oxidized to CO<sub>2</sub> during the RE6 oxidation phase; °C). We also computed the amount of centennially stable SOC from RE6 parameters using the model developed in Cécillon et al. (2018).  </p><p> </p><p>Our results showed that no clear effect of OWPs addition can be established for the youngest site (6 years). On the contrary, OWPs amendments had a clear effect on SOC quantity and quality at the sites having experienced 18 and 20 years of OWPs addition. For these sites, OWPs amendments increased SOC content, decreased SOC thermal stability (T50 CO<sub>2</sub> oxidation) and increased the Rock-Eval 6® Hydrogen Index (HI) compared to control plots. OWPs amendments tended to increase slightly the amount of centennially stable SOC at the sites having experienced 20 years of repeated OWPs application. Our results suggest that if OWPs addition does increase SOC content, at least in the long run, the majority of this additional SOC is labile and may be quickly lost if OWPs additions are stopped.</p><p> </p><p>References:</p><p>Barré P., Plante A.F., Cécillon L., Lutfalla S., Baudin F., Bernard S., Christensen B.T., Eglin T., Fernandez J.M., Houot S., Kätterer T., Le Guillou C., Macdonald A., van Oort F. & Chenu C. (2016) The energetic and chemical signatures of persistent soil organic matter. Biogeochemistry, 130: 1-12.</p><p>Cécillon L., Baudin F., Chenu C., Houot S., Jolivet R., Kätterer T., Lutfalla S., Macdonald A.J., van Oort F., Plante A.F., Savignac F., Soucémarianadin L.N. & Barré P. (2018) A model based on Rock-Eval thermal analysis to quantify the size of the centennially persistent organic carbon pool in temperate soils. Biogeosciences, 15, 2835-2849.</p>

scholarly journals Differential long-term effects of climate change and management on stocks and distribution of soil organic carbon in productive grasslands

2012 ◽  
Vol 9 (1) ◽  
pp. 1055-1096 ◽  
Author(s):  
A. M. G. De Bruijn ◽  
P. Calanca ◽  
C. Ammann ◽  
J. Fuhrer
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Climate Change Scenarios ◽  
Long Term Effects ◽  
Organic C ◽  
Soil C ◽  
The Impact ◽  
Soc Stocks

Abstract. We studied the impact of climate change on the dynamics of soil organic carbon (SOC) stocks in productive grassland systems undergoing two types of management, an intensive type with frequent harvests and fertilizer applications and an extensive system where fertilization is omitted and harvests are fewer. The Oensingen Grassland Model was explicitly developed for this study. It was calibrated using measurements taken in a recently established permanent sward in Central Switzerland, and run to simulate SOC dynamics over 2001–2100 under three climate change scenarios assuming different elements of IPCC A2 emission scenarios. We found that: (1) management intensity dominates SOC until approximately 20 yr after grassland establishment. Differences in SOC between climate scenarios become significant after 20 yr and climate effects dominate SOC dynamics from approximately 50 yr after establishment, (2) carbon supplied through manure contributes about 60% to measured organic C increase in fertilized grassland. (3) Soil C accumulates particularly in the top 10 cm soil until 5 yr after establishment. In the long-term, C accumulation takes place in the top 15 cm of the soil profile, while C content decreases below this depth. The transitional depth between gains and losses of C mainly depends on the vertical distribution of root senescence and root biomass. We discuss the importance of previous land use on carbon sequestration potentials that are much lower at the Oensingen site under ley-arable rotation and with much higher SOC stocks than most soils under arable crops. We further discuss the importance of biomass senescence rates, because C balance estimations indicate that these may differ considerably between the two management systems.

scholarly journals Soil organic carbon dynamics from agricultural management practices under climate change

2021 ◽  
Vol 12 (4) ◽  
pp. 1037-1055
Author(s):  
Tobias Herzfeld ◽  
Jens Heinke ◽  
Susanne Rolinski ◽  
Christoph Müller
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Management Practices ◽  
Residue Management ◽  
Biophysical Model ◽  
Management Systems ◽  
Climate Change Scenarios ◽  
Warm Temperate ◽  
Soc Stocks

Abstract. Sequestration of soil organic carbon (SOC) on cropland has been proposed as a climate change mitigation strategy to reduce global greenhouse gas (GHG) concentrations in the atmosphere, which in particular is needed to achieve the targets proposed in the Paris Agreement to limit the increase in atmospheric temperature to well below 2 ∘C. We analyze the historical evolution and future development of cropland SOC using the global process-based biophysical model LPJmL, which was recently extended by a detailed representation of tillage practices and residue management (version 5.0-tillage2). We find that model results for historical global estimates for SOC stocks are at the upper end of available literature, with ∼2650 Pg C of SOC stored globally in the year 2018, ∼170 Pg C of which is stored in cropland soils. In future projections, assuming no further changes in current cropland patterns and under four different management assumptions with two different climate forcings, RCP2.6 and RCP8.5, results suggest that agricultural SOC stocks decline in all scenarios, as the decomposition of SOC outweighs the increase in carbon inputs into the soil from altered management practices. Different climate change scenarios, as well as assumptions on tillage management, play a minor role in explaining differences in SOC stocks. The choice of tillage practice explains between 0.2 % and 1.3 % of total cropland SOC stock change in the year 2100. Future dynamics in cropland SOC are most strongly controlled by residue management: whether residues are left on the field or harvested. We find that on current cropland, global cropland SOC stocks decline until the end of the century by only 1.0 % to 1.4 % if residue retention management systems are generally applied and by 26.7 % to 27.3 % in the case of residue harvest. For different climatic regions, increases in cropland SOC can only be found for tropical dry, warm temperate moist, and warm temperate dry regions in management systems that retain residues.

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

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

<p>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°C objective of the Paris Agreement on Climate. The “4per1000” initiative was launched in 2015 as a climate mitigation option, with an aspiration to increase global soil organic carbon (SOC) stocks by 4‰ per year to compensate for the anthropogenic emissions of carbon dioxide in the atmosphere. The “4per1000” 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.</p><p>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: “What is the amount of carbon inputs that needs to be brought to soils as a means to increase SOC stocks by 4‰ per year?” 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.</p><p>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.</p><p>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.</p>

Soil Organic Matter stability along altitudinal gradients in the French Alps

2020 ◽  
Author(s):  
Jérôme Poulenard ◽  
Norine Khedim ◽  
Lauric Cecillon ◽  
Amélie Sailard ◽  
Pierre Barré ◽  
...  
Keyword(s):  
Climate Change ◽  
Thermal Analysis ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Permanent Plots ◽  
Altitudinal Gradients ◽  
French Alps ◽  
Fresh Organic Matter ◽  
Rock Eval ◽  
Alpine Environments

<p>High-elevation ecosystems are considered as systems that have accumulated large amounts of organic carbon in their soils over the past millennia. However, there are still large uncertainties about soil organic matter (SOM) stocks and stability in mountain areas . The fate of SOM in alpine environments is particularly questioned in the context of climate change.</p><p>The aim of this study was to investigate SOM stocks and biogeochemical characteristics of SOM along altitudinal gradients to decipher their climatic and biogeochemical drivers. To do so, we used the soil samples set of the French ORCHAMP long-term observatory network. ORCHAMP is built around multiple altitudinal gradients (ca. 1000m of elevation gain representative of the pedoclimatic variability of the French Alps. Each gradient is made of 5 to 8 permanent plots distributed regularly each 200 m of elevation, from the valley (1000 m a.s.l.) to the mountain top (until 3000 m a.s.l.). We studied 18 elevational gradients, including 105 soil profiles and 350 soil horizons. The biogeochemical stability of SOM was estimated with Rock-Eval® thermal analysis.</p><p>SOM stocks are extremely variable and do not increase with elevation . The size of the thermally labile SOM  pool strongly increases with elevation. The high lability of SOM revealed by Rock-Eval® thermal analysis suggests a generally high vulnerability of SOM to climate change in alpine environments. The mechanisms explaining the maintenance of this SOM pool in alpine environments are still under study. Hypotheses involving complex balances between climate, nature of fresh organic matter, and enzymatic activities will be discussed.</p><p> </p>

Projected soil organic carbon stocks in German croplands under different climate change scenarios

2020 ◽  
Author(s):  
Catharina Riggers ◽  
Christopher Poeplau ◽  
Axel Don ◽  
Cathleen Frühauf ◽  
René Dechow
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Arable Land ◽  
Future Climate Change ◽  
Climate Projections ◽  
Climate Change Scenarios ◽  
Model Ensemble ◽  
C Input ◽  
Soc Stocks

<p>Mineralization of soil organic carbon (SOC) is driven by temperature and soil moisture. Thus, climate change might affect future SOC stocks with implications for greenhouse gas fluxes from soils and soil fertility of arable land. We used a model ensemble of different SOC models and climate projections to project SOC stocks in German croplands up to 2099 under different climate change scenarios of the Intergovernmental Panel of Climate Change. Current SOC stocks and management data were derived from the German Agricultural Soil Inventory. We estimated the increase in carbon (C) input required to preserve or increase recent SOC stocks. The model ensemble projected declining SOC stocks in German croplands under current management and yield levels. This was true for a scenario with no future climate change (-0.065 Mg ha<sup>-1</sup> a<sup>-1</sup>) as well as for the climate change scenarios (-0.070 Mg ha<sup>-1</sup> a<sup>-1</sup> to -0.120 Mg ha<sup>-1</sup> a<sup>-1</sup>). Thereby, preserving current SOC stocks would require an increase in current C input to the soil of between 51 % (+1.3 Mg ha<sup>-1</sup>) and 93 % (+2.3 Mg ha<sup>-1</sup>). We further estimated that a C input increase of between 221 % and 283 % would be required to increase SOC stocks by 34.4 % in 2099 (4 ‰ a<sup>-1</sup>). The results of this study indicate that increasing SOC stocks under climate change by a noticeable amount will be challenging since SOC losses need to be overcompensated.</p>

scholarly journals Differential long-term effects of climate change and management on stocks and distribution of soil organic carbon in productive grasslands

2012 ◽  
Vol 9 (6) ◽  
pp. 1997-2012 ◽  
Author(s):  
A. M. G. De Bruijn ◽  
P. Calanca ◽  
C. Ammann ◽  
J. Fuhrer
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Climate Change Scenarios ◽  
Long Term Effects ◽  
Organic C ◽  
Soil C ◽  
The Impact ◽  
Soc Stocks

Abstract. We studied the impact of climate change on the dynamics of soil organic carbon (SOC) stocks in productive grassland systems undergoing two types of management, an intensive type with frequent harvests and fertilizer applications and an extensive system without fertilization and fewer harvests. Simulations were conducted with a dedicated newly developed model, the Oensingen Grassland Model. It was calibrated using measurements taken in a recently established permanent sward in Central Switzerland, and run to simulate SOC dynamics over 2001–2100 under various climate change scenarios assuming different elements of IPCC A2 emission scenarios. We found that: (1) management intensity dominates SOC until approximately 20 years after grassland establishment. Differences in SOC between climate scenarios become significant after 20 years and climate effects dominate SOC dynamics from approximately 50 years after establishment. (2) Carbon supplied through manure contributes about 60 % to measured organic C increase in fertilized grassland. (3) Soil C accumulates particularly in the top 10 cm of the soil until 5 years after establishment. In the long-term, C accumulation takes place in the top 15 cm of the soil profile, while C content decreases below this depth. The transitional depth between gains and losses of C mainly depends on the vertical distribution of root senescence and root biomass. We discuss the importance of previous land use on carbon sequestration potentials that are much lower at the Oensingen site under ley-arable rotation with much higher SOC stocks than most soils under arable crops. We further discuss the importance of biomass senescence rates, because C balance estimations indicate that these may differ considerably between the two management systems.

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