Nutrient recycling in a hydroponic tomato crop

Abstract

A comparative analysis of nutrient solution (NS) recycling and non-recycling treatments in a hydroponic tomato crop was studied. The aims of the study were to measure nutrient concentration variations along the productive cycle in both treatments, to clarify the differences regarding fruit yield and to assess recycling system viability. Emitter and drained nutrient solution samples from both treatments were analyzed once per week, tomato samples were collected three times per week and they were measured and weighed. It was concluded that the average nitrate concentration in the inlet of the recycling treatment was 11.60 meq/l. The concentration increased by 7.01% in the leachate solution. The average sulfate concentration was 8.07 meq/l in the recycling system supplied solution, and 146.47% higher in leachates. Three analyzed nutrients, i.e. phosphate, potassium and ammonium, presented a lower concentration in the drained solution than in the supplied solution. Fruit yield was not increased by the recycling technique in the hydroponic crop. Recycling treatment viability has to be measured in terms of water and fertilizer savings and minimization of polluting waste in drainage solutions.