Agronomic parameters assessment in hydroponic tomato crop

In this study we present the results of a comparative analysis of nutrient solution (NS) recycling and non-recycling treatments in hydroponic tomato crop. The established aims are to evaluate water consumption, pH and conductivity variation along the productive cycle in both treatments, to establish the differences in fruit yield and to assess the viability of the recycling system. Watering times and drained nutrient solution volume were counted on a daily basis. Emitter and drained water samples from both treatments were analyzed once per week in the Agricultural Institute of Fraisoro (Gipuzkoa). Tomato samples were collected, weighed and measured three times per week once the harvest had started. There was an 8% reduction in water supply; irrigation excess was between 11-38% and water supply efficiency was 6.7% higher in the recycling treatment in comparison to the non-recycling treatment. Drainage pH values fluctuated from 3.9-7.6 and conductivity varied from 1.9-3.6 mS/cm. Average yield per plant was 7.17 kg/plant. No significant differences were found regarding fruit yield, except for the commercialized smaller size tomatoes (diameter 57-67 mm) whose production was 226% higher in the non-recycling area. Fruit yield was not increased by the recycling technique in hydroponic crop. Recycling treatment viability has to be measured in terms of water and fertilizers saving and minimization of polluting waste in drainage solutions.