Climatic changes in Central Italy and their potential effects on corn water consumption

This study evaluates the trends of meteorological and agrometeorological indices computed at different sites in the Region of Umbria (Central Italy). The indices were selected on the basis of whether they enable the evaluation of the potential effects of climatic changes on agricultural water requirements and management. The meteorological stations were preliminarily selected considering the length and entirety of the data series and a homogeneous spatial coverage of the region under study. The daily rainfall and minimum and maximum temperature data collected at the stations were elaborated to calculate meteorological and agrometeorological indices (for corn, widespread irrigated crop in Central Italy). The results of the analysis show that rainfall has decreased generally everywhere and the temperature has either remained unchanged or have increased. In particular, in two areas an asymmetric warming results in a decreasing evapotranspiration level. The trends, when present, are stronger in southeastern Umbria; this observation is valid for all the meteorological and agrometeorological indices analysed. At some sites the risk of crop damage due to frost has decreased and sowing time in spring can be anticipated; increasing trends in crop water requirements are expected only when high positive trends in reference evapotranspiration and negative trends in precipitation occur at the same time. Therefore, the regulating function of the soil water zone and the specific plant ability to modify its phenology seem to mitigate the water shortage peaks and the irrigation water requirement potential trends.