Water and fertilizers productivity in closed and open hydroponic systems of tomato production

Abstract

The amount of water and fertilizers used in the production of vegetables, specifically tomatoes ( Solanum lycopersicum L.) is high. This study was conducted to determine water and fertilizer productivity in closed and open hydroponic system for tomato production in greenhouse. Two treatments with eight replications were assessed; each replication consisted of 67 pots with two plants each. One treatment was a closed hydroponic system (with nutrient solution recirculation), and the other was an open hydroponic system (with non-recirculating nutrient solution). We quantified the amounts of water and fertilizers applied, as well as losses (drained nutrient solution), in the two treatments during the entire cycle. Also, we measured different parameters in the nutrient solution: electric conductivity, pH, volume applied, and volume drained; and in plants: total weight of fruits (25 pickings). There were no significant differences between the two treatments in fruit production. Water productivity was 59.53 kg fruit m -3 for the closed system and 46.03 kg fruit m -3 in the open system. The productivity of the fertilizers was higher in the closed system, 22.68% more efficiency was obtained with respect to the open system. Tomato production in the closed hydroponic system was higher by 13.50 kg fruit m -3 of water and there were applied 10.31 grams less of fertilizer per kilogram of fruit produced in relation to the open system.