Effects of salinity on the development of rocket grown on different substrates hydroponic.

This study evaluated the effects of salinity on the nutrient solution on the production of rocket, grown on different substrates. The test was developed in an environment protected by the Department of Environmental Sciences and Technology, Federal Rural University of the Semi-Arid in Mossoro-RN, housed in a completely randomized design in a factorial 3 x 5 with three replications. Five salinity levels of nutrient solution were used, obtained with or without the fish farming wastewater (S1-0.5, S2-2.0, S3-3.5, S4-5.0 and S5-6.5 dS m-1) and three substrates (SUB1-Mix coconut fibre + sand + rice husk (1:1:1), SUB2-Cambisol and SUB3-SUB1 reused in the previous experiment). Harvesting of rocket was performed at 35 days after sowing and evaluated the following variables: plant height, leaf number, leaf area, fresh weight, and dry weight. The salinity of the nutrient solution negatively affected the development of the rocket grown, having effect varying according to the type of substrate used. The plants grown on the substrate formed by the mixture of coconut fibre + sand + rice hulls (1:1:1) showed higher tolerance to salinity. The substrate formed by mixing coir + sand + rice husk can be recommended for growing rocket containers, but cannot be reused without treatment.