scholarly journals Conventional tillage vs. organic farming in relation to soil organic carbon stock in olive groves in Mediterranean rangelands (Southern Spain)

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.

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.


Agronomy ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 208
Author(s):  
Małgorzata Szostek ◽  
Ewa Szpunar-Krok ◽  
Renata Pawlak ◽  
Jadwiga Stanek-Tarkowska ◽  
Anna Ilek

The aim of the study was to compare the effect of conventional, simplified, and organic farming systems on changes in the content of soil organic carbon, organic matter fractions, total nitrogen, and the enzymatic activity. The research was conducted from 2016–2018 on arable land in the south-eastern part of Poland. The selected soils were cultivated in conventional tillage (C_Ts), simplified tillage (S_Ts), and organic farming (O_Fs) systems. The analyses were performed in soil from the soil surface layers (up to 25 cm depth) of the experimental plots. The highest mean contents of soil organic carbon, total nitrogen, and organic matter fractions were determined in soils subjected to the simplified tillage system throughout the experimental period. During the study period, organic carbon concentration on surface soil layers under simplified tillage systems was 31 and 127% higher than the soil under conventional tillage systems and organic farming systems, respectively. Also, the total nitrogen concentration in those soils was more than 40% and 120% higher than conventional tillage systems and organic farming systems, respectively. Moreover, these soils were characterised by a progressive decline in SOC and Nt resources over the study years. There was no significant effect of the analysed tillage systems on the C:N ratio. The tillage systems induced significant differences in the activity of the analysed soil enzymes, i.e., dehydrogenase (DH) and catalase (CAT). The highest DH activity throughout the experiment was recorded in the O_Fs soils, and the mean value of this parameter was in the range of 6.01–6.11 μmol TPF·kg−1·h−1. There were no significant differences in the CAT values between the variants of the experiment. The results confirm that, regardless of other treatments, such as the use of organic fertilisers, tillage has a negative impact on the content of SOC and organic matter fractions in the O_Fs system. All simplifications in tillage reducing the interference with the soil surface layer and the use of organic fertilisers contribute to improvement of soil properties and enhancement of biological activity, which helps to maintain its productivity and fertility.


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

&lt;p&gt;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.&lt;/p&gt;


2020 ◽  
Author(s):  
Yan Zhang

&lt;p&gt;Improvements in management practices can prevent the decline of soil organic carbon (SOC) storage caused by conventional tillage&amp;#160;practice in Northeast China. Density and size fractionation can track the transformation of plant residue into SOC and its location&amp;#160;in soil matrix. We used a long-term field study&amp;#160;in China&amp;#160;to evaluate these changes as a result of improved management involving tillage and cropping systems. Experimental treatments included no-till&amp;#160;(NT)&amp;#160;and moldboard ploughing&amp;#160;(MP)&amp;#160;under monoculture maize&amp;#160;(Zea mays&amp;#160;L.) (MM) and maize-soybean (Glycine max Merr.) rotation (MS); these were compared to the traditional management involving conventional tillage&amp;#160;(CT)&amp;#160;under MM. An&amp;#160;incubation&amp;#160;study&amp;#160;was conducted to evaluate mineralization and the biodegradability of SOC. The soils were also physically fractionated by density (light fraction, LF) and size (sand, silt, clay). With improved management, the SOC storage&amp;#160;in the clay&amp;#160;showed the largest increase across&amp;#160;all fractions. This increase was greater for MS than MM. The NTMS treatment resulted in a decline in silt-OC storage compared to CTMM. The&amp;#160;SOC mineralization&amp;#160;(mg CO&lt;sub&gt;2&lt;/sub&gt;-C g&lt;sup&gt;-1&lt;/sup&gt;&amp;#160;soil)&amp;#160;was affected by tillage and driven by LF-OC&amp;#160;and was observed in the order: NTMM&amp;#160;(2.06) &gt; MPMM&amp;#160;(1.72) &amp;#8776;&amp;#160;NTMS (1.71)&amp;#160;&gt;&amp;#160;CTMM (1.52) &amp;#8776;&amp;#160;MPMS (1.41). Both cropping and depth affected the biodegradability of SOC. Considering the plough layer (0-20 cm), treatments under MM had larger proportion of biodegradable SOC than under MS.&amp;#160;We conclude that the significant differences in SOC storage in physical fractions and SOC biodegradation were caused by differences in soil management.&lt;/p&gt;


Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2230
Author(s):  
Blanca Sastre ◽  
Belén Álvarez ◽  
Omar Antón ◽  
Maria Ángeles Pérez ◽  
Maria Jose Marques ◽  
...  

Olive groves on the Mediterranean Basin are usually managed by continuous tillage and low organic matter inputs, leading to several soil degradation processes. Groundcovers (GCs) have come out as an alternative soil management strategy to improve soil’s fertility, soil’s organic matter quantity, and the sustainability of agro-ecosystems. Nevertheless, farmers are still unwilling to implement GCs or reduce tilling frequency while there are still some uncertainties and lack of global analyses. The purpose of this study was to perform an assessment of the effects of using GC on the soil parameters microbiological biomass, crop yield, and olive oil quality. A field trial was performed on a gypsiferous soil in central Spain with three different GCs: permanent GC of Brachypodium distachyon (BRA); permanent GC of spontaneous vegetation (SVE), and annual GC of Vicia ervilia (BIT) to be compared with conventional tillage (TIL). After three years, numbers of nematodes, fungi, and bacteria were higher on plant roots regardless of GC composition. BRA was the treatment with the biggest impact on soil and yield parameters. BRA increased soil organic carbon 1.03 Mg ha−1 yr−1 at 0–10 cm depth but reduced significantly olive yield because of nitrogen competition. The BIT treatment improved soil organic carbon stocks and soil structure, and did not reduce olive yield significantly regarding TIL. The BIT treatment was considered the best soil management strategy in semiarid conditions.


Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 291
Author(s):  
Ramón Bienes ◽  
Maria Jose Marques ◽  
Blanca Sastre ◽  
Andrés García-Díaz ◽  
Iris Esparza ◽  
...  

Long-term field trials are essential for monitoring the effects of sustainable land management strategies for adaptation and mitigation to climate change. The influence of more than thirty years of different management is analyzed on extensive crops under three tillage systems, conventional tillage (CT), minimum tillage (MT), and no-tillage (NT), and with two crop rotations, monoculture winter-wheat (Triticum aestivum L.) and wheat-vetch (Triticum aestivum L.-Vicia sativa L.), widely present in the center of Spain. The soil under NT experienced the largest change in organic carbon (SOC) sequestration, macroaggregate stability, and bulk density. In the MT and NT treatments, SOC content was still increasing after 32 years, being 26.5 and 32.2 Mg ha−1, respectively, compared to 20.8 Mg ha−1 in CT. The SOC stratification (ratio of SOC at the topsoil/SOC at the layer underneath), an indicator of soil conservation, increased with decreasing tillage intensity (2.32, 1.36, and 1.01 for NT, MT, and CT respectively). Tillage intensity affected the majority of soil parameters, except the water stable aggregates, infiltration, and porosity. The NT treatment increased available water, but only in monocropping. More water was retained at the permanent wilting point in NT treatments, which can be a disadvantage in dry periods of these edaphoclimatic conditions.


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.


Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 484
Author(s):  
Andrew M. Bierer ◽  
April B. Leytem ◽  
Robert S. Dungan ◽  
Amber D. Moore ◽  
David L. Bjorneberg

Insufficient characterization of soil organic carbon (SOC) dynamics in semi-arid climates contributes uncertainty to SOC sequestration estimates. This study estimated changes in SOC (0–30 cm depth) due to variations in manure management, tillage regime, winter cover crop, and crop rotation in southern Idaho (USA). Empirical data were used to drive the Denitrification Decomposition (DNDC) model in a “default” and calibrated capacity and forecast SOC levels until 2050. Empirical data indicates: (i) no effect (p = 0.51) of winter triticale on SOC after 3 years; (ii) SOC accumulation (0.6 ± 0.5 Mg ha–1 year–1) under a rotation of corn-barley-alfalfax3 and no change (p = 0.905) in a rotation of wheat-potato-barley-sugarbeet; (iii) manure applied annually at rate 1X is not significantly different (p = 0.75) from biennial application at rate 2X; and (iv) no significant effect of manure application timing (p = 0.41, fall vs. spring). The DNDC model simulated empirical SOC and biomass C measurements adequately in a default capacity, yet specific issues were encountered. By 2050, model forecasting suggested: (i) triticale cover resulted in SOC accrual (0.05–0.27 Mg ha–1 year–1); (ii) when manure is applied, conventional tillage regimes are favored; and (iii) manure applied treatments accrue SOC suggesting a quadratic relationship (all R2 > 0.85 and all p < 0.0001), yet saturation behavior was not realized when extending the simulation to 2100. It is possible that under very large C inputs that C sequestration is favored by DNDC which may influence “NetZero” C initiatives.


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


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