Rocket production (eruca sativa mill.) in a floating system using peracetic acid as oxygen source compared with substrate culture

Rocket (Eruca sativa Mill.) is a green leafy vegetable that is increasingly used as an ingredient in salad. The floating system is a way to grow this crop, at high density from sowing to harvest and easy to use in relation substrate culture, and it is well known water culture can be limited by hypoxia. Few studies have examined the use of peroxides or peracetic acid in nutrient solutions as a source of oxygenation. The aim of the study was to evaluate the rocket grown in substrates as compared to the floating system, with a stabilized mixture of peracetic acid in the nutrient solution. The experiment was carried out in and Talca (Chile) from October to November 2008. The treatments were substrate culture perlite and composted pine bark (1:1); floating system with trays filled with the same substrate and 0, 40 and 80 mg·L^-1 of stabilized peracetic acid mix (PA). The fresh and dry weight of rocket leaves at harvest we evaluated. We recorded total nutrient solution uptake; the average dissolved oxygen; pH and electrical conductivity (EC). A randomized complete block design with four replicates was conducted using Tukey's multiple range test (P < 0.05). The results suggest from 40 to 80 mg·L^-1 PA applied to the nutrient solution, increases the fresh and dry weight in the rocket crop grown by floating system and may compensate this limiting factor in the growth, if it was compared with higher oxygen available substrate culture.