PRODUCCIÓN DE FORRAJE VERDE HIDROPÓNICO DE CEBADA (Hordeum vulgare) USANDO EFLUENTE DE PISCIGRANJA DE TRUCHAS/PRODUCTION OF GREEN HYDROPONIC FORAGE OF BARLEY (Hordeum vulgare) USING TROUT FARM'S EFFLUENT

The objective was to determine the effect of trout farm effluent on the production of green hydroponic forage of barley (GHF). The activities were: oxidation of ammonia (N-NH4^sup +^) in the trout farm effluent to nitrate of nitrogen (N-NO^sub 3^^sup -^) in a biofilter (nitrification), and the use of this effluent in the production of GHF. Design was completely randomized with three treatments: 100% of water from water supply channel (T0), 50% of water from biofilter effluent, plus 50% of water from water supply channel (T1), and 100% of water from biofilter effluent (T2); with 10 replications. Variables assessed were: development time of biofilter; N-NO^sub 3^^sup -^ content in fully developed biofilter; percentage of protein and plant height on 4th, 8th, 12th, and 16th day production; and biomass production of GHF on 16th day. By the end of the 90th day, the biofilter installed to generate N-NO^sub 3^^sup -^ was developed at a medium pH of 8.23 and at a medium temperature of 14.9°C. N-NO^sub 3^^sup -^ content (mg/L) in biofilter effluent was 2.2 while trout farm effluent was 1.2. No significant difference was found in protein percentage of GHF (P