Use of satellite-based phenometrics, geophysical soil data and a semi-distributed agro-hydrological model for variable-rate irrigation management in a maize farm in northern Italy

In the most recent agricultural seasons water scarcity problems in many areas of the Po plain had become more frequent; thus, the introduction of irrigation-saving methods and technologies is becoming essential, especially in areas that cannot benefit from a large availability of surface water resources. In the context of precision irrigation, aimed at increasing water and energy productivity at the farm scale by operating a spatial and temporal variable-rate irrigation if needed, agro-hydrological models play a crucial role. In this study, remote-sensed phenometrics and biophysical crop parameters, and delineation of homogeneous management zones through an electromagnetic induction (EMI) sensor, were used to parametrize a semi-distributed mechanistic agro-hydrological model in the case of a 300-ha maize farm located in Brescia (northern Italy). The modelling system was applied to simulate irrigation use in the current situation and in the case of an optimized and variable rate irrigation management. Average results for the period 2016-2020 showed a water and energy saving of about 20% in the case of the optimized irrigation management, confirmed by savings achieved in a pilot pivot in which the modelling procedure was used in 2021 to support the irrigation scheduling in combination with 7-days weather forecast data.