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

Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria di ricerca, Centro di ricerca Viticoltura ed Enologia, Via Casamassima, 148, 70010 Turi (BA), Italia

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.