Effects of management on soil organic carbon and structural stability in olive grove toposequences in Mediterranean areas.

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>

2021 ◽  
Author(s):  
Dimitris Triantakonstantis ◽  
Spyros Detsikas

<p>Soil organic carbon (SOC) is the carbon that remains in the soil after the partial decomposition of any material produced by living organisms. It is an essential parameter for agricultural production, the potential sequestration of CO₂ in soil and a vital soil function for global carbon cycle. However, a vast potential of soil carbon is removed from agricultural soils due to non-sustainable soil management practices. Mapping SOC and its changes over time and space is highly valuable for estimating the CO₂ emissions and effects of climate change to the environment. In the present work, the Greek National Map of SOC is presented calculating the SOC stock in 30 arc-seconds spatial resolution using the Global Soil Partnership and Food and Agriculture Organization of the United Nations (FAO) guidelines for SOC mapping. The presented methodology considers the reference framework of the SCORPAN model for digital soil mapping, which can predict SOC stocks in correspondence with soil forming factors. Among the key variables used for estimating SOC stocks are environmental covariates such as climate and meteorological data, thematic maps, digital terrain data, geomorphometry and soil data. Data mining and geostatistical techniques (random forests, support vector machines, regression-kriging) are used to estimate the SOC stocks. Internal and external map accuracy is used to evaluate the performance of the Greek National SOC map. Accuracy of FAO’s methodology was examined herein using different modelling approaches. As indicated in the results, the most accurate map was produced by the random forest technique and an accuracy of FAC2=0.968, RMSE=0.322 and r=0.756. The main findings are also discussed herein covering aspects relevant to the method implementation, validation and feasibility of operational implementation.</p><p><strong>Keywords: </strong>soil organic carbon, climate change, soil management practices, Greek National Map</p>


2014 ◽  
Vol 6 (1) ◽  
pp. 35-70 ◽  
Author(s):  
L. Parras-Alcántara ◽  
B. Lozano-García

Abstract. Soil organic carbon (SOC) concentration is a soil variable subject to changes. In agricultural soils, the management system is a key factor that influence to these changes. For determine the management system effects on SOC stocks (SOC-S) in olive groves, 114 soil profiles were studied in the Los Pedroches Valley (Mediterranean rangelands – southern Spain) for long-term (20 yr). The management practices were conventional tillage (CT) and organic farming (OF) in four soil types: Cambisols (CM), Regosols (RG), Luvisols (LV) and Leptosols (LP). Soil properties were statistically analyzed by management techniques, soil types and horizons. The principal components analyses identified four factors that explained 65% of the variance. Also, significant differences (p < 0.05) were found between soil types and management techniques. Equally was observed that the management system affected to SOC-S. In addition, the total SOC-S for 20 yr increased in OF with respect to CT by 72% and 66% in CM and LV respectively. The SOC showed significant differences for horizons (p < 0.05) in relation to the management types. The stratification ratio index of SOC was >2 in all studied soils. These results indicate high soils quality, and that management practices affect to SOC store in the Los Pedroches Valley.


2020 ◽  
Author(s):  
Deborah Linsler ◽  
Jacqueline Gerigk ◽  
Ilka Schmoock ◽  
Rainer Georg Jörgensen ◽  
Martin Potthoff

&lt;p&gt;Reduced tillage is assumed to be a suitable practice to maintain and promote microbial biomass and microbial activity in the soil. The microbial biomass in particular is considered as a sensitive indicator for detecting soil disturbances. The objective of this study was to quantify the influence of different tillage practices on microbial parameters in the soil. Furthermore, we analyzed the relation of those microbial parameters with site-specific conditions.&lt;/p&gt;&lt;p&gt;To get a deeper insight in that topic, soils from different fields of agricultural farms with different tillage practices in France (12 fields), Romania (15 fields) and Sweden (17 fields) were examined within the &amp;#8220;SoilMan project&amp;#8221;. The tillage practices were no-tillage (absence of any tillage), minimum tillage (non-inversion tillage for instance by chisel plough or cultivator) and conventional tillage (inversion tillage by ploughing), all of which were carried out for at least five years prior to sampling. Soil samples were taken in spring 2018 from all fields under winter wheat (Triticum aestivum) at three soil depths (0-10 cm, 10-20 cm, 20-30 cm). As microbial parameters we measured microbial biomass carbon and nitrogen contents, ergosterol contents (as proxy for fungi) and basal respiration rates. For site-specific conditions we measured soil organic carbon, total nitrogen and total phosphorus contents, texture, pH and the soil water content.&lt;/p&gt;&lt;p&gt;Results show that microbial biomass carbon and nitrogen were more affected by soil type and soil texture as well as climatic conditions (mean precipitation and temperature) than by tillage practices. For instance, an increased clay content had a positive effect on the microbial biomass and, in addition to the higher average annual temperature, explained the generally low values &amp;#8203;&amp;#8203;in France. The lack of inversion tillage primarily led to stratified levels of soil organic carbon, microbial biomass carbon and ergosterol contents, which can be explained by the lack of crop residue incorporation. There were hardly any differences in microbial indicators between the tillage intensities when looking at the whole of the sampled soil profile (0-30 cm). In France, the microbial biomass carbon / soil organic carbon ratio was lower for no-tillage than for conventional tillage, which may indicate, among other things, that the mechanically ground organic matter incorporated into the soil under conventional tillage was better colonized by microorganisms. However, this effect could not be confirmed in the other countries. The metabolic quotient was generally increased at the lowest sampled depth (20-30 cm), irrespective of the cultivation.&lt;/p&gt;&lt;p&gt;We can conclude that the soil tillage intensity influenced the distribution of microbial biomass carbon and soil organic carbon contents more strongly than the total amounts in the sampled soil profile and that the soil texture had a greater impact on microbial soil properties than the agricultural management practice.&lt;/p&gt;


2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Martin Wiesmeier ◽  
Christopher Poeplau ◽  
Carlos A. Sierra ◽  
Harald Maier ◽  
Cathleen Frühauf ◽  
...  

2013 ◽  
Vol 726-731 ◽  
pp. 3832-3836
Author(s):  
Song Wei Jia

For the last decades, because of increasing attention to global change, the carbon cycle in the terrestrial ecosystem has become a hotspot problem for every country. It has 1.6 Pg/a C to release into atmosphere because of the irrational land-use, quickening the step of global warming trend. But agricultural soil has the double-sword effects. If improper soil tillage practices are adopted, agricultural soil may become the source of carbon dioxide in the atmosphere. And if adopting effective management measurement and scientific tillage technology, agricultural soil may become carbon sink. This paper reviewed the effects of conventional tillage and conservation tillage on soil organic carbon (SOC), and found that conservation tillage has a huge potential for sequestrating organic carbon compared with conventional tillage. Finally, the important significance of agriculture soil carbon sequestration was discussed in detail.


Solid Earth ◽  
2014 ◽  
Vol 5 (1) ◽  
pp. 299-311 ◽  
Author(s):  
L. Parras-Alcántara ◽  
B. Lozano-García

Abstract. Soil organic carbon (SOC) concentration is a soil variable subject to changes. The management system is a key factor that influences these changes. To determine the long-term effects of the management system on SOC stocks (SOCS) in olive groves, 114 soil profiles were studied in the Los Pedroches Valley (Mediterranean rangelands – southern Spain) for 20 years. The management practices were conventional tillage (CT) and organic farming (OF) in four soil types: Cambisols (CMs), Regosols (RGs), Luvisols (LVs) and Leptosols (LPs). Soil properties were statistically analysed by management techniques, soil types and horizons. Significant differences (p < 0.05) were found between soil types and management practices. It was equally observed that the management system affected SOCS. In addition, the total SOCS during the 20-year experiment increased in OF with respect to CT by 72 and 66% in CMs and LVs respectively. SOC showed significant differences for horizons (p < 0.05) in relation to the management type. The stratification ratio (SR) was used as an indicator of soil quality based on the influence of surface SOC levels on erosion control, water infiltration and nutrient conservation with respect to deep layers. The SR of SOC from the surface to depth was greater in CT compared to OF with the exception of RGs. In all cases, the SR of SOC was >2. These results indicate high soil quality and that management practices affect SOC storage in the Los Pedroches Valley.


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 ◽  
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.


Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1139
Author(s):  
Yun-Ya Yang ◽  
Avi Goldsmith ◽  
Ilana Herold ◽  
Sebastian Lecha ◽  
Gurpal S. Toor

Soils represent the largest terrestrial sink of carbon (C) on Earth, yet the quantification of the amount of soil organic carbon (SOC) is challenging due to the spatial variability inherent in agricultural soils. Our objective was to use a grid sampling approach to assess the magnitude of SOC variability and determine the current SOC stocks in three typical agricultural fields in Maryland, United States. A selected area in each field (4000 m2) was divided into eight grids (20 m × 25 m) for soil sample collection at three fixed depth intervals (0–20 cm, 20–40 cm, and 40–60 cm). Soil pH in all fields was significantly (p < 0.05) greater in the surface soil layer (6.2–6.4) than lower soil layers (4.7–5.9). The mean SOC stocks in the surface layers (0–20 cm: 1.7–2.5 kg/m2) were 47% to 53% of the total SOC stocks at 0–60 cm depth, and were significantly greater than sub-surface layers (20–40 cm: 0.9–1.3 kg/m2; 40–60 cm: 0.8–0.9 kg/m2). Carbon to nitrogen (C/N) ratio and stable C isotopic composition (δ13C) were used to understand the characteristics of SOC in three fields. The C/N ratio was positively corelated (r > 0.96) with SOC stocks, which were lower in sub-surface than surface layers. Differences in C/N ratios and δ13C signatures were observed among the three fields. The calculated values of SOC stocks at 0–60 cm depth ranged from 37 to 47 Mg/ha and were not significantly different in three fields likely due to the similar parent material, soil types, climate, and a short history of changes in management practices. A small variability (~10% coefficient of variation) in SOC stocks across eight sampling grids in each field suggests that re-sampling these grids in the future can lead to accurately determining and tracking changes in SOC stocks.


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