Worldwide, Mediterranean cropping systems face the complex challenge of producing enough high-quality food while preserving the quantity and quality of scarce water for people and agriculture in the context of climate change. While good management of nitrogen (N) is paramount to achieving this objective, the efficient strategies developed for temperate systems are often not adapted to the specificities of Mediterranean systems. In this work, we combine original data with a thorough literature review to highlight the most relevant drivers of N dynamics in these semi-arid systems. To do so, we provide an analysis at nested scales combining a bottom-up approach from the field scale, with a top-down approach considering the agro-food system where cropping systems are inserted. We analyze the structural changes in the agro-food systems affecting total N entering the territory, the contrasting response of yields to N availability under rainfed and irrigated conditions in a precipitation gradient, the interaction between N management and climate change adaptation, the main drivers affecting the release of Nr compounds (nitrate, ammonia, nitric oxide and nitrous oxide) compared with temperate systems and finally, the behavior of N once exported to highly regulated river networks. We conclude that sustainable N management in Mediterranean cropping systems requires the specific adaptation of practices to particular local agro-environmental characteristics with special emphasis on water availability for rainfed and irrigated systems. This approach should also include a systemic analysis of N input into the territory that is driven by the configuration of the agro-food system.

No abstract

Crop multi-model ensembles (MME) have proven to be effective in increasing the accuracy of simulations in modelling experiments. However, the ability of a MME to capture crop response to changes in sowing dates and densities has not yet been investigated. These management interventions are some of the main levers for adapting cropping systems to climate change. Here, we explore the performance of a MME of 29 wheat crop models to predict the effect of changing sowing dates and rates on yield and yield components, on two sites located in a high-yielding environment in New Zealand. The experiment was conducted for 6 years and provided 50 combinations of sowing date, sowing density and growing season.”. We show that the MME simulates seasonal growth of wheat well under standard sowing conditions, but fails under early sowing and high sowing rates. The comparison between observed and simulated in-season fraction of intercepted photosynthetically active radiation (FIPAR) for early sown wheat shows that the MME does not capture the decrease of crop above ground biomass during winter months due to senescence. Models need to better account for tiller competition for light, nutrients and water during vegetative growth, and early tiller senescence and tiller mortality, which are exacerbated by early sowing, high sowing densities and warmer winter temperatures.

<p>Agricultural practices and technologies play a crucial role in the adaptation to climate change and disaster risk reduction, especially in contexts of high social and environmental vulnerability as in the Meso American Dry Corridor. This area, home to more than 40 million people and half of the smallholders basic grain farmers, is highly sensitive to El Niño phenomenon, associated to 30-40% decrease of precipitation and long periods of water shortages. This in turn makes agricultural production difficult to success and maintain subsistence livelihoods of the rural poor. Thus, adaptation to climate variability is key for sustainable development in the dry corridor.</p><p>In this study we develop a methodology to systematically review Good Agricultural Practices (GAP) for climate change adaptation and disaster risk reduction to gain a comprehensive overview of adaptation options that can guide policy recommendations at the local level. The food-water-energy nexus approach has been considered in this methodology.</p><p>The methodology starts analyzing good agricultural practices (GAP) already identified in the Meso American Dry Corridor documented by different types of actors (International organizations, NGOs, local and national governments, academia, private sector). They were classified in different agricultural subsectors (farming, livestock, agroforestry, forestry and fishing and aquaculture) regarding climate variability and several natural hazards such as drought and flood. Then, a live spread sheet database was developed where the best practices were organized following the criteria defined based on literature review and expert knowledge. These  criteria were established to assess each potential good practice taking into account agroecological adequacy, socioeconomic viability, increase in resilience and environmental co-benefits, and specific consideration to the water-energy nexus. Finally, a group of 145 GAP were identified for the region.</p><p>Most of the GAP correspond to crop production, and they are mostly related to drought management and coping with interannual climate variability. It is observed that GAP are frequently implemented as a combination of practices and techniques as well as to face several hazards at the same time. In this regard, the analysis of water resources and the energy component should be seen under the food-water-energy nexus approach to ensure that a complete assessment of a potential GAP.</p>

Metodología para el monitoreo y evaluación de buenas prácticas en agricultura para la adaptación al cambio climático y la gestión integral del riesgo de desastres Con participación de: Con apoyo de:Con participación de: Con apoyo de:Metodología para el monitoreo y evaluación de buenas prácticas en agricultura para la adaptación al cambio climático y la gestión integral del riesgo de desastres