Vine performance of ‘Italia' table grape in relation to organic soil amendment

Abstract

The following research took place during the 2018 − ‘19 season in ‘Italia' table grape vineyard in Apulia. Four treatments were compared: no fertilized (T), organic amendment fertilized (B) at rate of 5.0 ton/hectare, equivalent at the rate of 100 Kg N ha−1, 75 Kg P2O5 ha−1 and 75 Kg K202 ha−1; mineral fertilized (M) at the same rate of N, P2O5 and K2O of organic fertilized vines and finally a cover crops treatment with a mixture of vetch, pea and lentil (S). Leaf gas exchange during summer season shown significant differences in term of net CO2 assimilation, stomatal conductance, transpiration onto organic fertilized vines respect to control vines. Vines fertilized with organic amendment shown a better water status during warmest summer days since organic compounds improve the soil-water holding capacity. Compared to unfertilized vines, vines fertilized with organic amendment have shown a significant increase in yield per vine (+ 32%) in relation to the highest cluster weight and the highest sugar content respect to mineral fertilized vines. Our results indicates that application of an high level of soil organic amendment on ‘Italia' table grape vines increase grapevines yield, berry solid soluble solid and have improved soil properties, contrasting summer drought effect.