Use of the VegSyst v3 model to simulate seasonal dry matter production, uptake of nutrients, and evapotranspiration in a greenhouse soilless tomato crop in Tuscany

This study explores the application of the VegSyst v3 model, developed in Spain for greenhouse soil-grown vegetable crops, to estimate dry matter production (DMP), evapotranspiration (ETc), and nutrient uptake in spring greenhouse soilless tomato in Italy. The cultivar Pisanello was chosen because it is particularly popular within the Tuscan region. The original VegSyst v3 model was calibrated to specific growing conditions in the Tuscan region for radiation use efficiency (RUE=3.90 and 2.20 after detopping instead of RUE=4.01) and crop coefficient (kc=1.45 instead of 1.00). The Almeria radiation model was used to estimate greenhouse reference evapotranspiration (ET₀). New dilution curves for magnesium (Mg) and phosphorus (P), expressed by the power equation %Mg = 0.60 × DMP^(-0.200) (R² = 0.94), and %P = 0.55 × DMP^(-150) (R² = 0.98), were introduced. These recalibrated Mg and P curves performed better in soilless system than the original dilution curve from VegSyst v3. The calibrated model demonstrated accurate predictions for DMP, ETc, the uptake of all macronutrients (N, P, K, Ca, Mg), and the uptake concentrations throughout the tomato-crop spring seasons. Moreover, the model was also preliminarily validated in a commercial farm of soilless tomato cultivation. The recalibrated VegSyst v3 model could be incorporated into a Decision Support System (DSS) to provide recommendations to farmers in Tuscany for managing the nutrient solution composition for soilless tomato crops in greenhouses.