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The area surrounding the Po River, known as the Po Valley, provides a central contribution in the economy of Italy and is highly devoted to agriculture. Recently it has been hit by multiple droughts, among which the exceptional event of summer 2022 is considered the worst dry period of the past 200 years. In the near future, the frequency of such exceptional events is predicted to rise; thus, a deep knowledge of the past droughts that hit the area, the variables used to characterize the events, the impacts they caused and the mitigation strategies adopted to deal with dry periods is of the utmost importance for policy definitions and planning. This study maps the scientific literature published from 2000 to February 2024 on the topic of drought in the Po Valley using the Scopus and Web of Science databases. Overall, 44 articles have been identified and grouped in three main classes: event identification and characterization, impact analysis and management strategies. The main gaps found in the collected papers are the lack of evaluations of the impacts of drought events on human health, hydroelectric energy production and tourism. Furthermore, comprehensive drought management and planning in the area is never addressed in the considered articles. The mentioned aspects deserve more attention, especially the development of drought management plans and policies and the evaluation of their effectiveness. [ABSTRACT FROM AUTHOR]

Drought and water stress negatively affect many human activities, with agriculture playing a crucial role in ensuring food security. The drought vulnerability assessment of agricultural systems has been widely investigated in the past and the relationship between drought hazard and losses has been traditionally expressed through vulnerability curves. This study develops maize drought vulnerability curves tailored to the context of the Po River Basin (Northern Italy) which is the largest Italian agricultural area and accounts for 35% of national crop production. The curves express the relationship between crop water stress and maize yield losses. Four crop growth stages are considered (establishment, vegetative, flowering and yield formation) since the sensitivity of maize to water stress is strictly related with the plant growth stage. In addition, the influence of soil texture on the maize response to water stress is investigated. The Agricultural Production System sIMulator (APSIM) is used to simulate the crop yield and the water stress. APSIM is calibrated on observed yield and the model skill in reproducing maize yield is satisfactorily verified (Pearson correlation coefficient equals to 0.87). Flowering is the most sensitive stage to water deficit independently from the soil texture, while the yield formation phase is most sensitive to water stress than the vegetative in the case of Loam soils. The achieved results suggest the importance of the use of appropriate irrigation strategies. Water should be provided to maize in case of a water stress during the flowering phase to avoid irreparable yield losses. [ABSTRACT FROM AUTHOR]