The DSS GeScoN for Managing Irrigation and N Fertilization in Vegetable Crops: Application in Processing Tomato Crop in Southern Italy

The work illustrates the theoretical basis, the methodological approach and the structure of a new decision support system program (GesCoN) designed for the management of N fertigation in vegetable crops. The methodological approach is based on daily water and N balance, considering the water lost by evapotranspiration and the N uptake by the crop as output and irrigation, net rainfall, N fertilization, N  mineralization from soil organic matter as main inputs. The software calculates on a daily basis the availability of water and N into the root zone, and assesses when to start a fertigation event and the amount of irrigation water and N fertiliser that has to be applied in order to fulfill the water and N-crop requirements. The models used by GesCoN  for the prediction of plant growth, including root apparatus geometry and its interaction with wet soil zones, N uptake as well as the approaches used for predicting N mineralization and the dynamics of N and water into the soil are also described. Water balance is done by estimating ET₀ through Penman-Montheit or a calibrated Hargreaves model. ETc can be estimated by using the single or dual Kc approach. The flow-chart of the program and the basic information for its functioning are described. The application of the DSS in a processing tomato crop including its parametrization in a Souther Italy environment, are also reported.