Climate change, variability and extreme events: risk assessment and management strategies in a Peach cultivated area in Italy

Climate change in Mediterranean area is likely to reduce precipitation amounts and to increase temperature thusaffecting the timing of development stages and the productivity of crops. Further, extreme weather events areexpected to increase in the future leading to significant increase in agricultural risk. Some strategies for effectivelymanaging risks and adapting to climate change involve adjustments to irrigation management and use of differentvarieties.We quantified the risk on Peach production in an irrigated area of "Emilia Romagna" region ( Italy) taking intoaccount the impact on crop yield due to climate change and variability and to extreme weather events as well asthe ability of the agricultural system to modulate this impact (adaptive capacity) through changes in water andcrop management.We have focused on climatic events causing insufficient water supply to crops, while taking into account theeffect of climate on the duration and timing of phenological stages. Further, extreme maximum and minimumtemperature events causing significant reduction of crop yield have been considered using phase-specific criticaltemperatures.In our study risk was assessed as the product of the probability of a damaging event (hazard), such as droughtor extreme temperatures, and the estimated impact of such an event (vulnerability). To estimate vulnerability wetook into account the possible options to reduce risk, by combining estimates of the sensitivity of the system(negative impact on crop yield) and its adaptive capacity. The latter was evaluated as the relative improvement dueto alternate management options: the use of alternate varieties or the changes in irrigation management.Vulnerability was quantified using cultivar-specific thermal and hydrologic requirements of a set of cultivars determinedby experimental data and from scientific literature. Critical temperatures determining a certain reductionof crop yield have been estimated and used to assess thermal hazard and vulnerability in sensitive phenologicalstages. Cultivar-specific yield response functions to water availability were used to assess the reduction of yieldfor a determinate management option.Downscaled climate scenarios have been used to calculate indicators of soil water availability and thermaltimes and to evaluate the variability of crop phenology in combination with critical temperatures. Two climatescenarios were considered: reference (1961-90) and future (2021-2050) climate, the former from climatic statisticson observed variables, and the latter from statistical downscaling of general circulation models (AOGCM).Management options were defined by combinations of irrigation strategies (optimal, rainfed and deficit) with useof alternate varieties.As regards hydrologic conditions, risk assessment has been done at landscape scale in all soil units within eachstudy area. The mechanistic model SWAP (Soil-Water-Atmosphere-Plant model) of water flow in the soil-plantatmospheresystem was used to describe the hydrological conditions in response to climate and irrigation.Different farm management options were evaluated. In a moderate water shortage scenario, deficit irrigation wasan effective strategy to cope with climate change risks. In a severe water shortage scenario, the study showed thepotentiality of intra-specific biodiversity to reduce risk of yield losses, although costs should be evaluated againstthe benefits of each specific management option.The work was carried out within the Italian national project AGROSCENARI funded by the Ministry forAgricultural, Food and Forest Policies (MIPAAF, D.M. 8608/7303/2008)