Abstract: Adaptation of agricultural systems to climate uncertainties requires the construction of scenarios that should take into account the complexities of socio-ecological systems of a specific local context. Adaptation scenarios of agricultural systems are not making forecasts or predictions, but prospective futures or future paths. They can facilitate our understanding of how systems work and evolve. Adaptation processes of agricultural systems involve a variety of changes in local practices and social organization. The development of adaptation scenarios at farm level entails a clear understanding of farmers’ frames that are mediated by their interests, experiences and internal and external forces. Farmers’ frames is the way in which farmers frame climate issues emphasizing vulnerabilities, uncertainties and opportunities (i.e: impacts on their farming systems) and open the window for searching adaptation strategies. This study reports on the methodologies for the development of explorative scenarios (i.e., scenarios that explore the future from a variety of perspectives) for the climate change adaptation of four agricultural systems (intensive dairy cattle, extensive dairy sheep, rice farming and horticulture) in the Oristano regional pilot study in Italy. Explorative scenarios were used to explore trends into the future from the past and present. Three research steps were followed: (i) in the first step farmers’ perceptions and prospective through semi-structured interviews and questionnaires were analysed; (ii) in the second step the evolution of the agricultural systems (i.e. temporal and spatial) was evaluated; (iii) the third step examined multiple stakeholders’ outlooks about farm-level possible adaptive strategies through interactive workshops.

Abstract: Agronomic research is important to identify suitable options for improving soil carbon (C) sequestration and reducing soil CO2 emissions. Therefore, the objectives of this study were i) to analyse the on-farm effects of different nitrogen fertilization sources on soil respiration, ii) to explore the effect of fertilization on soil respiration sensitivity to soil temperature (T) and iii) to assess the effect of the different fertilization regimes on the soil C balance. We hypothesized that i) the soil CO2 emission dynamics in Mediterranean irrigated cropping systems were mainly affected by fertilization management and T and ii) fertilization affected the soil C budget via different C inputs and CO2 efflux. Four fertilization systems (farmyard manure, cattle slurry, cattle slurry + mineral, and mineral) were compared in a double-crop rotation based on silage maize (Zea mays L) and a mixture of Italian ryegrass (Lolium multiflorum Lam.) and oats (Avena sativa L). The research was performed in the dairy district of Arborea, in the coastal zone of Sardinia (Italy), from May 2011 to May 2012. The soil was a Psammentic Palexeralfs with a sandy texture (940 g sand kg(-1)). The soil total respiration (SR), heterotrophic respiration (Rh), T and soil water content (SWC) were simultaneously measured in situ. The soil C balance was computed considering the Rh C losses and the soil C inputs from fertilizer and crop residues. The results showed that the maximum soil CO2 emission rates soon after the application of organic fertilizer reached values up to 121,1111 1 111(-2) s(-1). On average, the manure fertilizer showed significantly higher CO2 emissions, which resulted in a negative annual C balance (-2.9 t ha(-1)). T also affected the soil respiration temporal dynamics during the summer, consistently with results obtained in other temperate climatic regions that are characterized by wet summers and contrary to results from rainfed Mediterranean systems where the summer SR and Rh are constrained by the low SWC. The sensitivity of soil respiration to temperature significantly increased with C input from fertilizer. In conclusion, this research supported the hypotheses tested. Furthermore, the results indicated that i) soil CO2 efflux was significantly affected by fertilization management and T, and ii) fertilization with manure increased the soil respiration and resulted in a significantly negative soil C budget. This latter finding could be primarily explained by a reduction in productivity and, consequently, in crop residue with organic fertilization alone as compared to mineral, by the favourable SWC and T for mineralization, and by the sandy soil texture, which hindered the formation of macroaggregates and hence soil C stabilization, making fertilizer organic inputs highly susceptible to mineralization. (C) 2016 Elsevier B.V. All rights reserved.