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Background: Understanding the effects of climate change on agro-ecosystems is fundamental in order to select the optimum management practices to mitigate environmental pressures. There is a need to forecast greenhouse gas emissions (GHG) emissions of grassland systems under climate change scenarios whilst also accounting for SOC sequestration. The objective of this study is to assess the net GHG emissions over > 405,000 hectares (ha) of moist temperate Northern Spanish grasslands utilised for dairy production, under climate change conditions (i.e., RCP 4.5, and RCP 8.5), compared to a reference baseline scenario. It is hypothesised that net GHG will increase under climate change conditions and that implementing specific manure management practices (namely the anaerobic digestion (AD)) may mitigate the global warming effect. Methods: We used an integrated modelling framework comprising: (i) geographic information systems (GIS); (ii) a modified RothC version to simulate SOC changes in managed grasslands under moist temperate conditions; and (iii) Tier 2 recent IPCC methods to estimate GHG emissions. Results: Average net GHG emissions contributed to global warming potential with average emissions of 5.8 and 6.2 Mg CO2-e ha−1 year−1, under RCP 4.5 and RCP 8.5, respectively. Anaerobic digestion allowed net GHG under both climate change scenarios to equal net GHG under the baseline reference scenario. Conclusion: Under climate change conditions, implementing specific manure management practices, namely AD, will likely reduce the net GHG emissions of the grassland systems associated with dairy production in Northern Spain.

Crop diversification practices (CDPs) are alternative strategies aimed to achieve sustainable cropping systems and food production overcoming the agro-environmental impacts of conventional cropping systems such as monoculture. Thus, this paper aims to improve the knowledge of implementing CDPs in different European pedoclimatic regions by assessing the economic performance at the farm level. CDPs are compared with conventional cropping systems and clustered in terms of their gross margin (GM) results and variations. Farm-level assessment shows that CDPs provide positive economic results, representing an adaptive management strategy for ecological transition, without compromising economic sustainability. Particularly, the main findings show that (1) the impact of diversification depends more on crop type than on the selected CDPs, (2) most farms exhibited a low GM with low economic impact, and (3) there is a great likelihood that the CDPs facilitate the buildup of more resilient farming systems

Crop diversification practices (CDPs) are alternative strategies aimed to achieve sustainable cropping systems and food production overcoming the agro-environmental impacts of conventional cropping systems such as monoculture. Thus, this paper aims to improve the knowledge of implementing CDPs in different European pedoclimatic regions by assessing the economic performance at the farm level. CDPs are compared with conventional cropping systems and clustered in terms of their gross margin (GM) results and variations. Farm-level assessment shows that CDPs provide positive economic results, representing an adaptive management strategy for ecological transition, without compromising economic sustainability. Particularly, the main findings show that (1) the impact of diversification depends more on crop type than on the selected CDPs, (2) most farms exhibited a low GM with low economic impact, and (3) there is a great likelihood that the CDPs facilitate the buildup of more resilient farming systems.

Predicting the regional net greenhouse gas emissions (Net GHG) of grasslands is increasingly important, as these are one of the most globally widespread vegetation types, providing several ecosystem services. In this study, we assessed the regional soil organic carbon (SOC) change over a 30-year period (1981–2010), and the annual GHG balance for 405,000 ha of moist temperate Spanish grassland associated with dairy cow production. To do this we used the following: (i) an integrated modelling framework comprising geographic information systems (GIS); (ii) the RothC model to simulate SOC changes in managed grasslands under moist temperate conditions; and (iii) Tier 2 recent IPCC methods to estimate emissions. The results showed an average regional SOC change rate of 0.16 Mg C ha−1 year−1, associated with the initial SOC and livestock density. The annual GHG balance was positive, contributing to global warming by 5.6 Mg CO2-e ha−1 year−1. Livestock density was the main factor affecting net GHG emissions in the grasslands associated with dairy production in northern Spain. We determined a livestock density threshold of 0.95 LU ha−1, below which there is no SOC accumulation, and a threshold of approximately 0.4 LU ha−1, above which net GHG per livestock unit (LU) are reduced. In conclusion, our study confirms the importance of dairy cow grazing systems in preserving and/or enhancing SOC stocks in the grasslands of northern Spain. It is therefore crucial to optimise the livestock density considering large variety of feed intake and alternative manure management mitigation options to reduce the net GHG emissions. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Simulation models represent soil organic carbon (SOC) dynamics in global carbon (C) cycle scenarios to support climate‐change studies. It is imperative to increase confidence in long‐term predictions of SOC dynamics by reducing the uncertainty in model estimates. We evaluated SOC simulated from an ensemble of 26 process‐based C models by comparing simulations to experimental data from seven long‐term bare‐fallow (vegetation‐free) plots at six sites: Denmark (two sites), France, Russia, Sweden and the United Kingdom. The decay of SOC in these plots has been monitored for decades since the last inputs of plant material, providing the opportunity to test decomposition without the continuous input of new organic material. The models were run independently over multi‐year simulation periods (from 28 to 80 years) in a blind test with no calibration (Bln) and with the following three calibration scenarios, each providing different levels of information and/or allowing different levels of model fitting: (a) calibrating decomposition parameters separately at each experimental site (Spe); (b) using a generic, knowledge‐based, parameterization applicable in the Central European region (Gen); and (c) using a combination of both (a) and (b) strategies (Mix). We addressed uncertainties from different modelling approaches with or without spin‐up initialization of SOC. Changes in the multi‐model median (MMM) of SOC were used as descriptors of the ensemble performance. On average across sites, Gen proved adequate in describing changes in SOC, with MMM equal to average SOC (and standard deviation) of 39.2 (±15.5) Mg C/ha compared to the observed mean of 36.0 (±19.7) Mg C/ha (last observed year), indicating sufficiently reliable SOC estimates. Moving to Mix (37.5 ± 16.7 Mg C/ha) and Spe (36.8 ± 19.8 Mg C/ha) provided only marginal gains in accuracy, but modellers would

Soil organic C (SOC) stock assessments at the regional scale under climate change scenarios are of paramount importance in implementing soil management practices to mitigate climate change. In this study, we estimated the changes in SOC sequestration under climate change conditions in agricultural land in Spain using the RothC model at the regional level. Four Intergovernmental Panel on Climate Change (IPCC) climate change scenarios (CGCM2-A2, CGCM2-B2, ECHAM4-A2, and ECHAM4-B2) were used to simulate SOC changes during the 2010 to 2100 period across a total surface area of 2.33 ´ 104 km2. Although RothC predicted a general increase in SOC stocks by 2100 under all climate change scenarios, these SOC sequestration rates were smaller than those under baseline conditions. Moreover, this SOC response differed among climate change scenarios, and in some situations, some losses of SOC occurred. The greatest losses of C stocks were found mainly in the ECHAM4 (highest temperature rise and precipitation drop) scenarios and for rainfed and certain woody crops (lower C inputs). Under climate change conditions, management practices including no-tillage for rainfed crops and vegetation cover for woody crops were predicted to double and quadruple C sequestration rates, reaching values of 0.47 and 0.35 Mg C ha−1 yr−1, respectively.

[EN] An integrated assessment of the potential of different management practices for mitigating specific components of the total GHG budget (N2O and CH4 emissions and C sequestration) of Mediterranean agrosystems was performed in this study. Their suitability regarding both yield and environmental (e.g. nitrate leaching and ammonia volatilization) sustainability, and regional barriers and opportunities for their implementation were also considered. Based on its results best strategies to abate GHG emissions in Mediterranean agro-systems were proposed. Adjusting N fertilization to crop needs in both irrigated and rain-fed systems could reduce N2O emissions up to 50% compared with a non-adjusted practice. Substitution of N synthetic fertilizers by solid manure can be also implemented in those systems, and may abate N2O emissions by about 20% under Mediterranean conditions, with additional indirect benefits associated to energy savings and positive effects in crop yields. The use of urease and nitrification inhibitors enhances N use efficiency of the cropping systems and may mitigate N2O emissions up to 80% and 50%, respectively. The type of irrigation may also have a great mitigation potential in the Mediterranean region. Drip-irrigated systems have on average 80% lower N2O emissions than sprinkler systems and drip-irrigation combined with optimized fertilization showed a reduction in direct N2O emissions up to 50%. Methane fluxes have a relatively small contribution to the total GHG budget of Mediterranean crops, which can mostly be controlled by careful management of the water table and organic inputs in paddies. Reduced soil tillage, improved management of crop residues and agro-industry by-products, and cover cropping in orchards, are the most suitable interventions to enhance organic C stocks in Mediterranean agricultural soils. The adoption of the proposed agricultural practices will require farmers training. The global analysis of life cycle emissions associate

Agriculture in the Mediterranean basin is currently contributing to greenhouse gas emissions (GHG) and in the future is expected to be strongly affected by climate change. Increasing soil organic carbon (SOC) via soil organic matter (SOM) improvement is widely regarded as a way to both mitigate and adapt to climate change. Using as a case study the Mediterranean coastal area in Spain, which is regarded as one of the most intensively managed areas in Europe for orchards and horticultural cropping, we analyzed the potential for climate change mitigation of introducing different practices that are expected to increase SOC. We selected both as a single measure and in combination, cover cropping and application to the soil of the available underutilized exogenous organic matter (EOM), treated (e.g. composted or digested) or non-treated. These practices were compared against a baseline scenario that intended to reflect the current practices in the area (e.g. all livestock manure produced in the area is applied to the agricultural soil). We carried out a modelling exercise at the regional scale using the agricultural activity data and current climatic conditions as inputs. Modelling runs were performed coupling a widely used dynamic model of SOC turnover (RothC) with a model to simulate the GHG emissions from EOM processing or storage prior to soil application (SIMSWASTE). Results indicate that the most promising practice, considered as a single measure and with respect to the baseline, was introducing cover crops in woody cropping systems. This practice resulted in an increase of 0.44 Mg C ha−1 yr−1 during the first 20 years (range 0.41-0.52 Mg C ha−1 yr−1) and led to a total SOC accumulation of about 30 Tg C after 100 years. Amendment of all agricultural land with available underutilized EOM resulted in an increase of up to 0.09 Mg C ha−1 yr−1 (range 0.07-0.16 Mg C ha−1 yr−1) as a single measure (urban waste) and 0.13 Mg C ha−1 yr−1 (range 0.11-0.21 Mg C ha−1 yr−1) as a

Soil organic carbon stock (SOCS) assessments at a national level are essential in the climate change mitigation role. Our study provides the first assessment of the SOC stored in entire Spanish surface soils obtained from one sampling protocol within a regular sampling framework in a short edaphic time. In this study, we analysed topsoil samples (0-30cm) from 4401 locations. SOC, soil bulk density and stoniness were measured to estimate SOCS. The results showed that half the Spanish areas obtained a SOC value below 1%. There is inherently wide spatial variability in SOC contents in Spain with low SOC concentration levels located in southern areas. The lowest SOC levels were associated with agricultural soils. However, no statistically significant differences were found between forestlands and grasslands. The mean SOCS in the Spanish topsoil layer was 56.57MgCha-1 and the total stored in topsoil was 2.8 Pg C. We were surprised to find that our estimates were 40% lower than those known to date for Spain. The results herein highlight the potential land use change for SOC sequestration in Spanish soils. Certain changes in agricultural practises (conservation tillage) or converting some unproductive croplands into grasslands or forestlands can increase carbon sequestration in soils. © 2015 Elsevier B.V.