scholarly journals The Rock-Eval® signature of soil organic carbon in arenosols of the Senegalese groundnut basin. How do agricultural practices matter?

2020 ◽  
Vol 301 ◽  
pp. 107030
Author(s):  
Oscar Pascal Malou ◽  
David Sebag ◽  
Patricia Moulin ◽  
Tiphaine Chevallier ◽  
Ndeye Yacine Badiane-Ndour ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Agricultural Practices ◽  
Rock Eval

Does agricultural practices impact the quantity and the forms of organic carbon stored in cultivated soils of the Senegal groundnut basin? A Rock-Eval approach

2020 ◽  
Author(s):  
Oscar Pascal Malou ◽  
David Sebag ◽  
Patricia Moulin ◽  
Tiphaine Chevallier ◽  
Yacine Badiane Ndour ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Standard Deviation ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Agricultural Practices ◽  
Sandy Soils ◽  
Organic Wastes ◽  
Rock Eval ◽  
Cultivated Soils

<p>Soil organic carbon (SOC) is a key element in the functioning of agrosystems. It ensures soil quality and productivity of cultivated systems in the Sahelian region. This study uses Rock-Eval pyrolysis to examine how cultural practices impact SOC quantity and quality of cultivated sandy soils in the Senegal groundnut basin. Such thermal analysis method provides cost-effective information on SOC thermal stability that has been shown to be qualitatively related to SOC biogeochemical stability. Soils were sampled within 2 villages agricultural plots representative of local agricultural systems and for local preserved areas. Total SOC concentrations ranged from 1.8 to 18.5 g.kg<sup>-1</sup> soil (mean ± standard deviation: 5.6 ± 0.4 g.kg<sup>-1</sup> soil) in the surface layer (0-10 cm) and from 1.5 to 11.3 g.kg<sup>-1</sup> soil (mean ± standard deviation: 3.3 ± 0.2 g.kg<sup>-1</sup> soil) in 10-30 cm deep layer. SOC of cultivated soils significantly (p-value < 0.0001) decreased according to treatments in the following order: +organic wastes > +manure > +millet residues > no input. Our results show that the quantity and the quality of SOC are linked to each other and both depend on land-use and agricultural practices, especially the nature of organic inputs. This correlation is very strong in the tree plantation (R² = 0.98) and in the protected shrubby savanna (R<sup>²</sup> = 0.97). It remains important for cultivated soils receiving organic wastes (R² = 0.82), manure (R<sup>²</sup> > 0.75), or millet residues (R<sup>2</sup> = 0.91) but it’s no more significant in no-input situations. The Rock-Eval based indexes were depicted in a I/R diagram that illustrate the level of SOC stabilization and plotted against comparable results from literature. The Senegalese sandy soils have thermal signatures showing an inversion of the I and the R indexes compared to data from the literature and highlighting SOC stabilization as a function of soil depth. Indeed, the studied soils were characterized by a more abundant refractory pool (A5 which ranged from 7.7 to 21.3 % in 0-10 cm layer and from 12.5 to 24.3 % in 10-30 cm, respectively) compared to other tropical soils. The SOC in these sandy soils while positively affected by organic inputs is dominated by labile forms that mineralize quickly which is excellent for the needs of productivity of these agrosystems but not for mitigation of climate change.</p><p><strong>Keywords:</strong> Soil organic carbon; Organic inputs; Thermal analysis; Agrosystems; West Africa</p>

scholarly journals Mini review: Intensification of mulching to improve soil moisture in vanilla plantation

2018 ◽  
Vol 3 (2) ◽  
pp. 42
Author(s):  
I Gede Ketut Adiputra
Keyword(s):  
Global Warming ◽  
Soil Moisture ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Agricultural Practices ◽  
Basic Mechanism ◽  
Global Warming Scenario ◽  
The Impact ◽  
Evaporation Increase ◽  
Growth And Reproduction

Continuous water uptake from soil via the root system and it transport into the leaves system is a basic mechanism in plants to maintain growth and reproduction.  Consequently, sustaining soil moisture to keep water supply into the plants should continuously occurred to maintain growth.  Under condition of global warming scenario and robust agricultural practices, soil organic carbon which plays as a key for soil moisture and fertility are continuously diminished.  This condition could subsequently endanger the growth of shallow rooted plants, such as vanilla.  To mitigate the impact of global warming and robust agricultural practices, enhancing carbon sequestration to inhibit water loss is regarded crucial.  However, although mulch materials are locally available in most land crop plantations, those materials are rarely viewed as functional for maintaining soil moisture.  Both water stress and mulching might have not been seriously anticipated in conventional agricultural practices.  For example, continuous decreased in yield of vanilla plants are usually handled by applying pesticide or fertilizer, without addition of mulch.  The objective of this review was to gain a better understanding of soil moisture to increase vanilla growth and reproduction.  This review found that mulching could reduce evaporation, increase soil organic carbon and soil fertility.  It is concluded that intensification of mulching could enhance sustainability of vanilla plantations.  

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 A robust initialization method for accurate soil organic carbon simulations

2021 ◽  
Author(s):  
Eva Kanari ◽  
Lauric Cécillon ◽  
François Baudin ◽  
Hugues Clivot ◽  
Fabien Ferchaud ◽  
...  
Keyword(s):  
Machine Learning ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Co2 Concentration ◽  
Monitoring Networks ◽  
Machine Learning Model ◽  
Soc Stock ◽  
Rock Eval ◽  
New Generation

Abstract. Changes in soil organic carbon (SOC) stocks are a major source of uncertainty for the evolution of atmospheric CO2 concentration during the 21st century. They are usually simulated by models dividing SOC into conceptual pools with contrasted turnover times. The lack of reliable methods to initialize these models, by correctly distributing soil carbon amongst their kinetic pools, strongly limits the accuracy of their simulations. Here, we demonstrate that PARTYsoc, a machine-learning model based on Rock-Eval® thermal analysis optimally partitions the active and stable SOC pools of AMG, a simple and well validated SOC dynamics model, accounting for effects of soil management history. Furthermore, we found that initializing the SOC pool sizes of AMG using machine-learning strongly improves its accuracy when reproducing the observed SOC dynamics in nine independent French long-term agricultural experiments. Our results indicate that multi-compartmental models of SOC dynamics combined with a robust initialization can simulate observed SOC stock changes with excellent precision. We recommend exploring their potential before a new generation of models of greater complexity becomes operational. The approach proposed here can be easily implemented on soil monitoring networks, paving the way towards precise predictions of SOC stock changes over the next decades.

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

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1553
Author(s):  
Cornelia Rumpel ◽  
Abad Chabbi
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Food Security ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Agricultural Practices ◽  
Special Issue ◽  
Trade Offs ◽  
Reporting And Verification

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.

Predicting bi-decadal soil organic carbon mineralization with Rock-Eval® thermal analysis

2020 ◽  
Author(s):  
Pierre Barré ◽  
Laure Soucémarianadin ◽  
Baudin François ◽  
Chenu Claire ◽  
Bent Christensen ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Regression Models ◽  
Soil Samples ◽  
Organic C ◽  
Significant Regression ◽  
Rock Eval ◽  
Soc Mineralization

<p>The organic carbon reservoir of soils is a key component of climate change, calling for an accurate knowledge of the residence time of soil organic carbon (SOC). Existing proxies of the labile SOC pool such as particulate organic carbon or basal respiration tests are time consuming and unable to consistently predict SOC mineralization over years to decades. Similarly, models of SOC dynamics often yield unrealistic values of the size of SOC kinetic pools. Rock-Eval® 6 (RE6) thermal analysis of bulk soil samples has recently been shown to provide useful and cost-effective information regarding the long-term in-situ decomposition of SOC. The objective of this study was to design a method based on RE6 indicators to assess for a given soil, the proportion of SOC that will be mineralized in the coming 20 years.</p><p>To do so, we needed samples ready to be analyzed using RE6 with a known proportion of SOC mineralized in 20 years. We used archived soil samples from 4 long-term bare fallows and 8 C<sub>3</sub>/C<sub>4</sub> chronosequences. For each sample, the value of bi-decadal SOC mineralization was obtained from the observed SOC dynamics of its long-term bare fallow plot or the calculated C<sub>3</sub>-derived SOC decline following the conversion to C<sub>4</sub> plants. Those values ranged from 0.3 to 14.3 gC·kg<sup>−1</sup> (concentration data), representing 8.6 to 52.6% of total SOC (proportion data). All samples were analyzed using RE6 and simple linear regression models were used to predict bi-decadal SOC loss (concentration and proportion data) from 4 RE6 parameters: 1) HI (the amount of hydrogen-rich effluents formed during the pyrolysis phase of RE6; mgCH.g<sup>-1</sup> SOC), 2) OI<sub>RE6</sub> (the O recovered as CO and CO<sub>2</sub> during the pyrolysis phase of RE6; mgO<sub>2</sub>.g<sup>-1</sup> SOC), 3) PC/SOC (the amount of organic C evolved during the pyrolysis phase of RE6; % of total SOC) and 4) 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).</p><p>The RE6 HI parameter yielded the best predictions of bi-decadal SOC mineralization, for both concentration and proportion data. PC/SOC and T50 CO<sub>2</sub> oxidation parameters also yielded significant regression models. The OI<sub>RE6</sub> parameter was not a good predictor of bi-decadal SOC loss, with non-significant regression models. The results showed that SOC chemical composition (HI is a proxy for SOC H/C ratio), and to a lesser degree SOC thermal stability, are related to bi-decadal SOC dynamics. The RE6 thermal analysis method can therefore provide a quantitative and accurate estimate of SOC biogeochemical stability.</p>

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