Effect Of Fertilisation With Black Table Olive Wastewater Solutions On Production And Quality Of Tomatoes Cultivated Under Open Field Conditions

This studywas aimed atmaking progress on the valorisation of table olive wastewater that currently represent a big environmental problem for factories. Concentrates from vacuum evaporation of the wastewater generated during processing of black ripe olives treated with KOH were tested as fertilisers of tomato plants in open field assays for three consecutive crops. Fertilisation was performed by drip irrigation every 15 days; the first treatment being 15 days after transplanting, and a total of five fertilisation treatments were carried out. A phytotoxic effect was not observed on plants or fruit in any case but higher yield (fruit/plant and g/plant) was obtained in comparison to irrigationwith only tapwater. Moreover, the combined use of the olive concentratewith inorganic nitrogen supply (NH4NO3), in order to complywith the nutrient needs of plants, was also tested. The results demonstrated that the olive concentrates could be a good substitute for inorganic potassium (as KNO3) during the cultivation of tomato plants without any negative effect on the tomato quality (pH, degrees Brix, sugars, organic acids) or content of bioactive substances (phenolic compounds and carotenoids). (C) 2021 The Author(s). Published by Elsevier B.V.