Fertilizzazione e irrigazione delle colture in substrato: attuale stato dell’arte e tendenze future

The low water use efficiency, typical of soilless cultures, is mainly due to an inaccurate irrigation scheduling and the use of highly porous substrates. The increase of the water use efficiency of these cultures is also crucial for improving their nutrient use efficiency. An higher irrigation efficiency can be achieved only through an improvement of irrigation scheduling and, at least, by the reuse of drainage water. The paper focused on how to calculate the optimal irrigation volume and the frequency of the irrigation events. The optimal irrigation volume can be easily determined by the knowledge of the substrate retention curve and the type of container, using a software developed by the University of Pisa (CAL-VIR). The calculation of the irrigation frequency required the knowledge of the crop evapotranspiration. that could be estimated by evapotranspiration models (i.e. FAO model) or directly assessed by gravimetric methods or by root zone sensors (RZS), able to meaure the substrate volumetric water content. The use of controlled release fertilizers (CRF) and the fertigation are the main options adopted by the growers to feed the soilless culture crops. Finally, a free software (SOL-NUTRI), developed by the University of Pisa for the calculation of the nutrient solution, was described.