REUSE OF WATER FROM FISH FARMING AND ITS EFFECTS ON GAS EXCHANGE IN HYDROPONIC ARUGULAS

Abstract

Reusing water for agriculture can be an important alternative for expanding the sector. Given this, the objective of this study was to analyze the potential of water from fish farming in hydroponic arugula and its effects on gas exchange. The crop used was the arugula cultivar “folha larga”. The experimental design was subdivided plots (2 × 4), with four replications, with the plots having different circulation times (T1 = 15/15 minutes, and T2 = 15/30 minutes) and subplots with four mixtures of solutions (S1: 75% of the Fish Farming Water-FW and 25% of the nutrient solution: NS; S2: 50% of the FW and 50% of the NS; S3: 25% of the FW and 75% of the NS and S4: 100% of the NS). The variables obtained were photosynthesis, internal CO2 concentration and water use efficiency. Photosynthesis showed the best response with a recirculation time of 15 minutes, at which point plants reached higher levels with a nutrient solution concentration of 100%. In relation to the internal CO2 concentration and water use efficiency, the 15-minute circulation time provided higher values of these variables, while the solution composed of 68% NS and 32% FW presented the highest values. The use of water from fish farming has potential for use in arugula production without major interference in the gas exchange of this crop.