How does agroecology practices impact soil carbon stock and fluxes in a maize field?

Author(s):  
Nicolas L. Breil ◽  
Thierry Lamaze ◽  
Vincent Bustillo ◽  
Benoit Coudert ◽  
Solen Queguiner ◽  
...  

<p>Soil plays a major role on carbon cycle, through both carbon stock which is one of the most important carbon terrestrial pool and soil CO<sub>2</sub> efflux which represents one of the largest amounts of natural carbon emissions. It is known that soil respiration, through roots respiration and carbon mineralisation by microorganisms, is mainly controlled by temperature and humidity but the impact of crop management practices still needs to be investigated. Previous studies have demonstrated that crop management and more particularly reduced or no-tillage (NT) as well as cover-crops (CC) play a key role to mitigate soil respiration and increase soil organic carbon (SOC) content, but the impacts of the synergy of these practices are still unclear. Our study aims at better understanding the effect of sustainable agriculture through agroecological crop management practices on soil carbon dynamics.</p><p>Soil respiration was measured in south-west of France on two distinct sites, CAS in 2018 and ABA in 2019, characterized by different initial soil carbon content, 106.9 % higher in CAS than in ABA. Each site included two joint maize fields using agroecological (NT and CC, named Agroeco) and conventional (tillage and bare soil, named Conv) practises. Agroeco have been settled for 12 and 19 years at CAS and ABA, respectively, at the time of experiment. Soil respiration chamber as well as temperature and moisture sensors were used to collect data twice a month, while pedoclimatic variables were monitored continuously on each field. Soil samples were collected in the fields before the experiment to define SOC and nutrient content as well as physical properties, through the entire soil profile.</p><p>Mean soil respiration rate was higher on ABA-Agroeco (0.86 g CO<sub>2</sub> m<sup>-</sup>² h<sup>-1</sup>) than on ABA-Conv (0.50 g CO<sub>2</sub> m<sup>-</sup>² h<sup>-1</sup>) and was significantly correlated with soil temperature and humidity at Conv and only with soil temperature at Agroeco. Similar relations were found at CAS but with lower soil respiration rates. SOC concentration for ABA in the top 0-15 cm was higher at Agroeco (13.4 g kg<sup>-1</sup>) than at Conv (8.0 g kg<sup>-1</sup>) but little difference was found at CAS where SOC was high. These results suggest that soil respiration rates depend less on soil humidity on Agroeco than on Conv because agroecology management practices both keep more water at the surface and store additional soil organic carbon in soils, inducing more activity through the carbon cycle with higher soil respiration rate. For both sites, agroecological practices induced higher SOC content compared to conventional ones, however, only for ABA site, soil respiration was higher for agroecological field while SOC content was higher. This study supports the idea that agroecological management practices can increase carbon cycle activity by increasing soil carbon stocks thus allowing the mitigation of greenhouse gases emissions and climate change, even by increasing soil CO<sub>2</sub> efflux.</p>

2018 ◽  
Author(s):  
Marwa Tifafi ◽  
Marta Camino-Serrano ◽  
Christine Hatté ◽  
Hector Morras ◽  
Lucas Moretti ◽  
...  

Abstract. Despite the importance of soil as a large component of the terrestrial ecosystems, the soil compartments are not well represented in the Land Surface Models (LSMs). Indeed, soils in current LSMs are generally represented based on a very simplified schema that can induce a misrepresentation of the deep dynamics of soil carbon. Here, we present a new version of the IPSL-Land Surface Model called ORCHIDEE-SOM, incorporating the 14C dynamic in the soil. ORCHIDEE-SOM, first, simulates soil carbon dynamics for different layers, down to 2 m depth. Second, concentration of dissolved organic carbon (DOC) and its transport are modeled. Finally, soil organic carbon (SOC) decomposition is considered taking into account the priming effect. After implementing the 14C in the soil module of the model, we evaluated model outputs against observations of soil organic carbon and 14C activity (F14C) for different sites with different characteristics. The model managed to reproduce the soil organic carbon stocks and the F14C along the vertical profiles. However, an overestimation of the total carbon stock was noted, but was mostly marked on the surface. Then, thanks to the introduction of 14C, it has been possible to highlight an underestimation of the age of carbon in the soil. Thereafter, two different tests on this new version have been established. The first was to increase carbon residence time of the passive pool and decrease the flux from the slow pool to the passive pool. The second was to establish an equation of diffusion, initially constant throughout the profile, making it vary exponentially as a function of depth. The first modifications did not improve the capacity of the model to reproduce observations whereas the second test showed a decrease of the soil carbon stock overestimation, especially at the surface and an improvement of the estimates of the carbon age. This assumes that we should focus more on vertical variation of soil parameters as a function of depth, mainly for diffusion, in order to upgrade the representation of global carbon cycle in LSMs, thereby helping to improve predictions of the future response of soil organic carbon to global warming.


Soil Research ◽  
2013 ◽  
Vol 51 (8) ◽  
pp. 615 ◽  
Author(s):  
W. E. Cotching ◽  
G. Oliver ◽  
M. Downie ◽  
R. Corkrey ◽  
R. B. Doyle

The effects of environmental parameters, land-use history, and management practices on soil organic carbon (SOC) concentrations, nitrogen, and bulk density were determined in agricultural soils of four soil types in Tasmania. The sites sampled were Dermosols, Vertosols, Ferrosols, and a group of texture-contrast soils (Chromosol and Sodosol) each with a 10-year management history ranging from permanent perennial pasture to continuous cropping. Rainfall, Soil Order, and land use were all strong explanatory variables for differences in SOC, soil carbon stock, total nitrogen, and bulk density. Cropping sites had 29–35% less SOC in surface soils (0–0.1 m) than pasture sites as well as greater bulk densities. Clay-rich soils contained the greatest carbon stocks to 0.3 m depth under pasture, with Ferrosols containing a mean of 158 Mg C ha–1, Vertosols 112 Mg C ha–1, and Dermosols 107 Mg C ha–1. Texture-contrast soils with sandier textured topsoils under pasture had a mean of 69 Mg C ha–1. The range of values in soil carbon stocks indicates considerable uncertainty in baseline values for use in soil carbon accounting. Farmers can influence SOC more by their choice of land use than their day-to-day soil management. Although the influence of management is not as great as other inherent site variables, farmers can still select practices for their ability to retain more SOC.


2021 ◽  
Author(s):  
◽  
Bridget Ellen O'Leary

<p>The global carbon cycle has been significantly modified by increased human demand and consumption of natural resources. Billions of tonnes of carbon moves between the Earth’s natural spheres in any given year, with anthropogenic activities adding approximately 7.1 gigatonnes (Gt) of carbon (C) to this flux. On a global basis, the sum of C in living terrestrial biomass and soils is approximately three times greater than the carbon dioxide (CO2) in the atmosphere; with the current soil organic carbon (OC) pool estimated at about 1500 Gt (Falkowski et al. 2000). With total global emissions of CO2 from soils being acknowledged as one of the largest fluxes in the carbon cycle, ideas and research into mitigating this flux are now being recognised as extremely important in terms of climate change and the reduction of green house gases (GHG) in the future. Additional co-benefits of increasing carbon storage within the soil are improvements in a soil’s structural and hydrological capacity. For example, increasing organic carbon generally increases infiltration and storage capacity of soil, with potential to reduce flooding and erosion. There are several management options that can be applied in order to increase the amount of carbon in the soil. Adjustments to land management techniques (e.g. ploughing) and also changes to cropping and vegetation type can increase organic carbon content within the subsurface (Schlesinger & Andrews, 2000). If we are able to identify specific areas of the landscape that are prone to carbon losses or have potential to be modified to store additional carbon, we can take targeted action to mitigate and apply better management strategies to these areas. This research aims to investigate issues surrounding soil carbon and the more general sustainability issues of the Gisborne/East-Cape region, North Island, New Zealand. Maori-owned land has a large presence in the region. Much of this land is described as being “marginal” in many aspects. The region also has major issues in terms of flooding and erosion. Explored within this research are issues surrounding sustainability, (including flooding, erosion, and Maori land) with particular emphasis on carbon sequestration potential and the multiple co-benefits associated with increasing the amount of carbon in the soil. This research consists of a desktop study and field investigations focusing on differences in soil type and vegetation cover/land use and what effects these differences have on soil OC content within the subsurface. Soil chemical and physical analysis was undertaken with 220 soil samples collected from two case-study properties. Particle size analysis was carried out using a laser particle sizer (LPS) to determine textural characteristics and hydraulic capacity. Soil organic carbon (OC) content was determined following the colorimetric method, wet oxidation (Blakemore et al. 1987), with results identifying large difference in soil OC quantification between sampled sites. National scale data is explored and then compared with the results from this field investigation. The direct and indirect benefits resulting from more carbon being locked up in soil may assist in determining incentives for better land-use and land management practices in the Gisborne/East-Cape region. Potentially leading to benefits for the land-user, the environment and overall general sustainability.</p>


2015 ◽  
Vol 3 (3) ◽  
pp. 267-274
Author(s):  
Agegnehu Shibabaw ◽  
Melkamu Alemeyehu

Soil organic carbon is the most important attribute and chosen as the most important indicator of soil and environment quality and agricultural sustainability. Maintaining of soil carbon stocks and other nutrient proved as the most important challenge of arable lands. It depends on soil type, surrounding climate and long term land use. Studies of various research reports indicates that agricultural management practice; crop rotation, residue management, reduced tillage, green manuring and organic matter amendment has identified for its contribution to the improvement of soil organic matter stocks and some other nutrients.Implementing of reduced or no tillage operation has underlined in increasing organic carbon stock of the soil through delaying of organic matter decomposition and N mineralization.Long term adoption of legume based crop rotation notably increases soil organic carbon and N contents, helped with natural gift of atmospheric nitrogen fixation. Organic sources of fertilizer are reservoirs of plant nutrients and organic carbon, and hence amendment with adequate and quality manure ultimately enhances the soil nutrients and SOC stocks of the soil. In general, soil and crop management practices allow the soil to sequester more atmospheric carbon in to the soil.The circumstances ultimately contribute to agricultural sustainability, environmental and soil quality and mitigation of climate change at large. 


2016 ◽  
Vol 40 (2) ◽  
pp. 197-208 ◽  
Author(s):  
Jean Dalmo de Oliveira Marques ◽  
Flávio Jesus Luizão ◽  
Wenceslau Geraldes Teixeira ◽  
Claudia Marie Vitel ◽  
Elizalane Moura de Araújo Marques

ABSTRACT The soil carbon under Amazonian forests has an important roles in global changing, making information on the soil content and depths of these stocks are considerable interest in efforts to quantify soil carbon emissions to the atmosphere.This study quantified the content and soil organic carbon stock under primary forest up to 2 m depth, at different topographic positions, at Cuieiras Biological Reserve, Manaus/ ZF2, km 34, in the Central Amazon, evaluating the soil attributes that may influence the permanence of soil carbon. Soil samples were collected along a transect of 850 m on topographic gradient Oxisol (plateau), Ultisol (slope) and Spodosol (valley). The stocks of soil carbon were obtained by multiplying the carbon content, soil bulk density and trickiness of soil layers. The watershed was delimited by using STRM and IKONOS images and the carbon contend obtained in the transects was extrapolated as a way to evaluate the potential for carbon stocks in an area of 2678.68 ha. The total SOC was greater in Oxisol followed by Spodosol and Ultisol. It was found direct correlations between the SOC and soil physical attributes. Among the clay soils (Oxisol and Ultisol), the largest stocks of carbon were observed in Oxisol at both the transect (90 to 175.5 Mg C ha-1) as the level of watershed (100.2 to 195.2 Mg C ha-1). The carbon stocks under sandy soil (Spodosol) was greater to clay soils along the transect (160-241 Mg C ha-1) and near them in the Watershed (96.90 to 146.01 Mg C ha-1).


2012 ◽  
Vol 518-523 ◽  
pp. 5112-5115
Author(s):  
Zhen Hong Xie ◽  
Bo Fu ◽  
Xiang Liu

Changes of soil organic carbon storage play an important role in carbon balance in the world. Firstly, analyzed the effect factors of the soil organic carbon changes that are limited to qualitative research instead of quantitative studies, and the main effect factors are climate and soil properties , but so far it is still unclear how the temperature changes affect soil organic carbon dynamical changes; then, summarized estimation methods of soil organic carbon storage, and the soil type method is more commonly used estimation method of soil carbon storage in china and abroad for simple method and the data easily accessible, and the study on soil organic carbon storage is static based on a point in time and is lack in dynamics analysis, therefore it is to be solved how to improve the estimation accuracy of soil carbon storage in the future; finally,summarized soil carbon cycle model at home and abroad, and it is a key point that the soil carbon cycle models combined with GIS and RS simulate large-scale soil carbon cycle in the future.


Soil Research ◽  
2013 ◽  
Vol 51 (8) ◽  
pp. 719 ◽  
Author(s):  
K. L. Page ◽  
R. C. Dalal ◽  
Y. P. Dang

Measures of particulate organic carbon (POC), humus organic carbon (HOC), and resistant organic carbon (ROC) (primarily char) are often used to represent the active, slow, and inert carbon pools used in soil carbon models. However, these fractions are difficult to measure directly, and mid infrared (MIR) spectroscopic techniques are increasingly being investigated to quantify these fractions and total organic carbon (TOC). This study examined the change in MIR-predicted pools of TOC, POC, HOC, and ROC in response to different crop management between two time periods (1981 and 2008) in a long-term wheat cropping trial in Queensland, Australia. The aims were (i) to assess the ability of MIR to detect changes in carbon stocks compared with direct measurements of TOC (LECO-TOC); and (ii) to assess how well the behaviour of POC, HOC, and ROC corresponded with the active, slow, and inert conceptual carbon pools. Significant declines in carbon stocks were observed over time using both LECO-TOC and MIR-predicted stocks of TOC, POC, HOC, and ROC, although MIR-TOC under-estimated loss by 27–30% compared with LECO-TOC. The decline in MIR-POC and MIR-HOC was consistent with the expected behaviour of the active and slow conceptual pools; however, the decline in ROC was not consistent with that of the inert pool. In addition, MIR measurements did not accurately detect differences in the rate of carbon loss under different crop management practices.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Tairui Liu ◽  
Daoli Peng ◽  
Zhijie Tan ◽  
Jinping Guo ◽  
Yunxiang Zhang

Abstract Background The carbon pools of forest soils play a vital role in global carbon sequestration and emissions. Forest management can regulate the sequestration and output of forest soil carbon pools to a certain extent; however, the kinetics of the effects of forest density on soil carbon pools require further investigation. Methods We established sample plots with stand density gradients in three different aged Larix principis-rupprechtii plantations and quantified the soil respiration, soil organic carbon (SOC), soil dissolved organic carbon (DOC), microbial biomass carbon (MBC), light fraction organic carbon (LFOC), and readily oxidized carbon (ROC). Results and conclusions During the growth and development of plantations, stand density is an essential factor that impacts soil respiration and its associated elements. Moderate density was observed to promote both the soil and heterotrophic respiration rates and the sequestration of MBC and LFOC, whereas it inhibited the sequestration of ROC. The soil, heterotrophic, and autotrophic respiration rates of older forest stands were relatively rapid, whereas the contents of SOC, MBC, LFOC, DOC, and ROC were higher and more sensitive to changes in stand density. The MBC, LFOC, and ROC in soil labile organic carbon were closely related to both the soil and heterotrophic respiration, but not the SOC. Among them, the LFOC and MBC played the roles of “warehouse” and “tool” and were significantly correlated with soil and heterotrophic respiration. The ROC, as a “raw material”, exhibited a significantly negative correlation with the soil and heterotrophic respiration. When the soil and heterotrophic respiration rates were rapid, the ROC content in the soil maintained the low level of a “dynamically stabilized” state. The stand density regulated heterotrophic respiration by affecting the soil labile organic carbon, which provided an essential path for the stand density to regulate soil respiration.


2008 ◽  
Vol 16 (NA) ◽  
pp. 93-111 ◽  
Author(s):  
Yuanying Peng ◽  
Sean C. Thomas ◽  
Dalung Tian

It is recognized that human activities, such as fossil fuel burning, land-use change, and forest harvesting at a large scale, have resulted in the increase of greenhouse gases in the atmosphere since the onset of the industrial revolution. The increasing amounts of greenhouse gases, particularly CO2 in the atmosphere, is believed to have induced climate change and global warming. With the ability to remove CO2 from the atmosphere through photosynthesis, forests play a critical role in the carbon cycle and carbon sequestration at both global and local scales. It is necessary to understand the relationship between forest soil carbon dynamics and carbon sequestration capacity, and the impact of forest management practices on soil CO2 efflux for sustainable carbon management in forest ecosystems. This paper reviews a number of current issues related to (1) carbon allocation, (2) soil respiration, and (3) carbon sequestration in the forest ecosystems through forest management strategies. The contribution made by forests and forest management in sequestrating carbon to reduce the CO2 concentration level in the atmosphere is now well recognized. The overall carbon cycle, carbon allocation of the above- and belowground compartments of the forests, soil carbon storage and soil respiration in forest ecosystems and impacts of forest management practices on soil respiration are described. The potential influences of forest soils on the buildup of atmospheric carbon are reviewed.


2021 ◽  
Author(s):  
Ilze Karklina ◽  
◽  
Andis Lazdins ◽  
Jelena Stola ◽  
Aldis Butlers ◽  
...  

Forest mineral soil is one of the terrestrial carbon pools, and changes in forest management practices can affect the carbon stock in forest soil. The purpose of the study is to estimate temporal fertilization impact on mineral soil organic carbon stock, depending on fertilizers applied, forest stand type, different dominant tree species of the stands. Coniferous and birch forest stands with mineral soil in the central and eastern part of Latvia were selected for the experiment. The fertilizers used were wood ash and nitrogen containing mineral fertilizer. No significant differences in organic carbon stock in O horizon were detected 2–5 years after fertilization. A tendency of smaller organic carbon stock in upper mineral soil layers (0–10 cm, 10–20 cm) was found in most part of objects. Significantly smaller organic carbon stock was found in upper mineral soil layers (0–10 cm and 10–20 cm) in birch stands with wet mineral soil treated with ammonium nitrate if compared to the control plots, possibly due to a different soil moisture regime of forest stands. The positive and significant correlations between soil organic carbon and nitrogen stocks were found in most part of the objects.


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