QUALITATIVE AND PRODUCTIVE RETURNS OF IRRIGATED SMALL BERRY TOMATOES

Abstract

Aims of the study were verifying productive responses in industrial cultivars of cherry tomato and set IRRINET water balance model calculation parameters for small berry tomatoes (crop coefficients, root zone development, duration of phenological phases). Trials have been performed in 2012 in two experimental sites in the Po plains on a loamy soil with a tendency to form crust, and on a silty-loamy soil with a tendency to cracking. Four small berry cultivars have been compared: ‘Mascalzone’ (mini San Marzano), ‘Kikko’ (cherry tomato), ‘Quorum’ and ‘Cesarino’ (mini-plum). Irrigation regimes were initially as follows: 70, 35 and 0% replenishment of estimated crop evapotranspiration (ETc), as for the results of previous experiments showing lesser water requirements of small berry tomato cultivars compared with traditional ones. Crop response to irrigation has been found proportional to water applied. Biomass (leaves and stems) as well as total and commercial yield were higher with 70% ETc treatment, due to a higher number of fruit per plant and average berry weight. As for quality, irrigation caused significant decrease of °Brix, but only in the 70% thesis. However, °Brix and lycopene yield per ha increased proportionally to total yield. ‘Mascalzone’ was the more productive cultivar, both in terms of fruit and aboveground vegetation biomass, showing greater water productivity. The reduction of 30% of processing tomato crop coefficient, as applied in this experiment, was found excessive, thus crop water requirements were underestimated. By recalculating the water balance without any crop coefficient reduction IRRINET model estimated and measured soil water volumetric contents were matching.