scholarly journals Soil organic carbon

2020 ◽  
Vol 119 (2) ◽  
pp. 053
Author(s):  
María Paz Salazar ◽  
Rafael Villarreal ◽  
Luis Alberto Lozano ◽  
María Florencia Otero ◽  
Nicolás Guillermo Polich ◽  
...  

Soil organic carbon (SOC) is an important factor for soil quality diagnosis. Physical and chemical fractionation of SOC are useful to characterize SOC, because some fractions are more sensitive indicators of the effects of different management practices. The aims of this study were (i) to determine values of SOC and different fractions of SOC at different depths and positions in an Argiudoll of the Argentinian Pampas under NT, and (ii) to determine the relation between physical and chemical fractions of SOC. In an experimental plot located in Chascomús, we determined SOC content, humic acids (HA), fulvic acids (FA), humins, coarse and fine particulate organic carbon (POCc and POCf) and mineral associated organic carbon (MOC), at different depths and in the row and inter-row. The content of SOC and different SOC fractions, as well as the contribution of each fraction to SOC showed a vertical variation. The contribution of HA and POCc (newer and more labile fractions) to SOC was larger in the surface than in deeper layers, while humins’ (older and more recalcitrant fraction) contribution to SOC increased with depth, and the contribution of FA, POCf and MOC to SOC remained relatively constant. There was no effect of row and inter-row in SOC content and composition. FA content was correlated to POCc, HA content to POCc and POCf and humins to MOC.

2016 ◽  
Vol 66 (1) ◽  
Author(s):  
Gustavo Alvarez Arteaga ◽  
Belina García Fajardo ◽  
María Estela Orozco Hernández ◽  
Patricia Mireles Lezama ◽  
Julieta Contreras Martínez

The loss of organic carbon stocks from the soil and their expulsion into the atmosphere due to the effect of anthropogenic activities must be understood as a problem that goes beyond the environmental to the social and economic context, with the soil degradation being just one of its many impacts. While the accumulation of carbon in the soil depends naturally on the interaction among a series of biotic and abiotic factors, management practices often cause the deterioration of its physical, chemical and biological properties, and, thus, increase the levels of mineralization and a reduction in carbon stocks. This research was undertaken in the municipality of San José del Rincón, State of Mexico, in volcanic soils under different conditions of soil use and disturbation time periods. Samples were obtained at 11 plots, on which physical and chemical analyses were undertaken, obtaining soil organic carbon stocks at 20 cm top soil. The results indicated that, for the soils used for agriculture and induced pasture, there were significant increases in the bulk density, greater acidity and a decrease in carbon concentration compared to forest soils. The organic carbon stocks taken from soils used in forestry, agriculture and induced pasture at a depth of 20 cm were 131, 53 and 63 Mg C ha-1 respectively, results which suggest the timing and intensity of management are determinants in the loss of soil organic carbon stocks from the soil, as well as the alteration of some of their physical and chemical properties.


2020 ◽  
Author(s):  
Manuel González-Rosado ◽  
Jesús Aguilera Huertas ◽  
Beatriz Lozano-García ◽  
Luis Parras-Alcántara

<p>Carbon sequestration in agricultural soils has been defined as a positive strategy to mitigate the climate change effects. To implement this strategy, it is necessary to reduce the soil physical disturbances that encourage its degradation. It is therefore essential to analyze the consequences that conventional tillage practices have on agrosystems as a first step towards developing sustainable management practices that are in line with strategies to combat climate change. In order to evaluate the conventional tillage impact in olive groves, a toposequence was carried out where three profiles of 50 cm depth each were opened in three topographical positions: summit, backslope and toeslope. The physical and chemical soil properties were analyzed, including soil organic carbon (SOC) and mean weight diameter (MWD) of the aggregates, which showed a plot scale low SOC levels and low MWD being subject to erosive processes which negatively impacts on its SOC storage capacity.</p>


Soil Research ◽  
2015 ◽  
Vol 53 (2) ◽  
pp. 113 ◽  
Author(s):  
R. Carbonell-Bojollo ◽  
E. J. González-Sánchez ◽  
M. Repullo Ruibérriz de Torres ◽  
R. Ordóñez-Fernández ◽  
J. Domínguez-Gimenez ◽  
...  

In dryland farming systems under a Mediterranean climate, soil quality and productivity can be enhanced by increasing the content of soil organic carbon (SOC) through alternative soil management systems. Some fractions of C are directly involved in increasing total SOC and therefore in enhancing any benefits in terms of soil properties. This study compares the viability of no-till farming (NT) with conventional (traditional) tillage (TT) for improving SOC levels. The influence of management practices was investigated for different fractions of C (particulate OC, active OC, humic acids, fulvic acids) and CO2 emissions in clayey soils in the south of Spain. The experiment was conducted over three farming seasons (2006–07, 2007–08 and 2008–09) covering a crop rotation of peas (Pisum sativum L.), wheat (Triticum aestivum L.) and sunflowers (Helianthus annuus L.). The NT system improved the levels of the different fractions of C in the surface soil and reduced the amount of CO2 released into the atmosphere compared with the TT system. Generally, the relationship between CO2 and SOC content was greater in soils under NT for the farming seasons sampled.


Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 650
Author(s):  
Jesús Aguilera-Huertas ◽  
Beatriz Lozano-García ◽  
Manuel González-Rosado ◽  
Luis Parras-Alcántara

The short- and medium—long-term effects of management and hillside position on soil organic carbon (SOC) changes were studied in a centenary Mediterranean rainfed olive grove. One way to measure these changes is to analyze the soil quality, as it assesses soil degradation degree and attempts to identify management practices for sustainable soil use. In this context, the SOC stratification index (SR-COS) is one of the best indicators of soil quality to assess the degradation degree from SOC content without analyzing other soil properties. The SR-SOC was calculated in soil profiles (horizon-by-horizon) to identify the best soil management practices for sustainable use. The following time periods and soil management combinations were tested: (i) in the medium‒long-term (17 years) from conventional tillage (CT) to no-tillage (NT), (ii) in the short-term (2 years) from CT to no-tillage with cover crops (NT-CC), and (iii) the effect in the short-term (from CT to NT-CC) of different topographic positions along a hillside. The results indicate that the SR-SOC increased with depth for all management practices. The SR-SOC ranged from 1.21 to 1.73 in CT0, from 1.48 to 3.01 in CT1, from 1.15 to 2.48 in CT2, from 1.22 to 2.39 in NT-CC and from 0.98 to 4.16 in NT; therefore, the soil quality from the SR-SOC index was not directly linked to the increase or loss of SOC along the soil profile. This demonstrates the time-variability of SR-SOC and that NT improves soil quality in the long-term.


2003 ◽  
Vol 83 (4) ◽  
pp. 363-380 ◽  
Author(s):  
A. J. VandenBygaart ◽  
E. G. Gregorich ◽  
D. A. Angers

To fulfill commitments under the Kyoto Protocol, Canada is required to provide verifiable estimates and uncertainties for soil organic carbon (SOC) stocks, and for changes in those stocks over time. Estimates and uncertainties for agricultural soils can be derived from long-term studies that have measured differences in SOC between different management practices. We compiled published data from long-term studies in Canada to assess the effect of agricultural management on SOC. A total of 62 studies were compiled, in which the difference in SOC was determined for conversion from native land to cropland, and for different tillage, crop rotation and fertilizer management practices. There was a loss of 24 ± 6% of the SOC after native land was converted to agricultural land. No-till (NT) increased the storage of SOC in western Canada by 2.9 ± 1.3 Mg ha-1; however, in eastern Canada conversion to NT did not increase SOC. In general, the potential to store SOC when NT was adopted decreased with increasing background levels of SOC. Using no-tillage, reducing summer fallow, including hay in rotation with wheat (Triticum aestivum L.), plowing green manures into the soil, and applying N and organic fertilizers were the practices that tended to show the most consistent in creases in SOC storage. By relating treatment SOC levels to those in the control treatments, SOC stock change factors and their levels of uncertainty were derived for use in empirical models, such as the United Nations Intergovernmental Panel on Climate Change (IPCC). Guidelines model for C stock changes. However, we must be careful when attempting to extrapolate research plot data to farmers’ fields since the history of soil and crop management has a significant influence on existing and future SOC stocks. Key words: C sequestration, tillage, crop rotations, fertilizer, cropping intensity, Canada


2011 ◽  
Vol 83 (4) ◽  
pp. 1313-1326 ◽  
Author(s):  
Giulliari A. S. T. Lira ◽  
Elcida L. Araújo ◽  
Maria Do Carmo Bittencourt-Oliveira ◽  
Ariadne N. Moura

The present study reports the phytoplankton abundance, dominance and co-existence relationships in the eutrophic Carpina reservoir, Pernambuco, Brazil. Sampling was carried out at six different depths bimonthly at a single reservoir spanning two climatic periods: dry season (January, September, and November 2006) and rainy season (March, May, and July 2006). Density, abundance, dominance, specific diversity and equitability of the community were determined, along with chlorophyll a, and physical and chemical variables of the environment. Eight species were considered abundant, and their densities corresponded to more than 90% of the total phytoplankton community quantified. Cyanobacteria represented more than 80% of this density. Cylindrospermopsis raciborskii was the only dominant taxon in the dry season, and was co-dominant in the rainy season. C. raciborskii, Planktothrix agardhii and Geitlerinema amphibium had the greatest densities and lowest vertical variation coefficients. The statistical analysis indicated relationships with vertical and seasonal variations in the phytoplankton community and the following variables: total dissolved solids, water temperature, electrical conductivity and pH. The changes in the environmental variables were discrete and regulated by the establishment of precipitation however, they were able to promote vertical and seasonal instability in the structure of the phytoplankton community.


2021 ◽  
Vol 17 ◽  
Author(s):  
Alec Mackay ◽  
Ronaldo Eduardo Vibart ◽  
Catherine McKenzie ◽  
Brian Devantier ◽  
Emma Noakes

In 2020 we measured the stability of soil organic carbon (SOC) concentrations and stocks under contrasting hill country pasture regimes, by sampling three slope classes and three aspect locations on each of three farmlets of a long-term phosphorus fertiliser and sheep grazing experiment. The farmlets included no annual phosphorus (NF), 125 kg of single superphosphate/ha (LF), or 375 kg superphosphate/ha (HF) that has been applied on an annual basis since 1980. Results from the 2020 sampling event were added to previous results reported from soil samples collected in 2003 and 2014. The SOC concentrations in the topsoil (0-75 mm depth), ranging from 4.23 to 5.99% across all slopes and aspects of the farmlets, fell within the normal range (≥3.5 and <7.0%) required for sustaining production and environmental goals. A trend was shown for greater SOC stocks in the topsoil in the HF farmlet (34.0 Mg/ ha) compared with the other two farmlets (31.6 Mg/ha), but this trend was not evident in the deeper soil layers (75-150, 150-300, 0-300 mm). Under the current conditions, topographical features such as slope and aspect had a more profound influence on SOC stocks than management history.


Sign in / Sign up

Export Citation Format

Share Document