Panicum maximum cultivars irrigated with fish farming effluent

Effluent from fish farming with saline water is a source of water, also rich in organic matter and nutrients,that can be used in irrigation of cultivated plants and even fully or partially replace mineral fertilization. The objective wasto evaluate the growth, biomass production and quality of P. maximum cultivars fertigated with fish farming effluent in agreenhouse experiment, using a randomized block design with eight replicates. Treatments were arranged in a split-split-plot scheme,with three irrigation managements in the plot (irrigation with public-supply water, irrigation with public-supply water + conventionalfertilization, and irrigation with fi sh farming effl uent), three cultivars of P. maximum (Tanzania, Mombasa, and Massai) in the sub-plot,and four cutting times in the sub-sub-plot (45, 90, 135, and 180 days after sowing). Plant height, number of tillers, production offresh biomass, neutral detergent fiber, acid detergent fiber, ether extract, crude protein, dry matter, and mineral matter contentswere analyzed. The highest growth, production, and quality of P. maximum grass occurs when irrigated with public-supplywater and under conventional NPK fertilization. Fertigation with fish farming effluent reduces the growth and production ofP. maximum grass, but allows obtaining better quality forage. It is possible to irrigate P. maximum grass using fish farmingeffluent with satisfactory yields. The growth of cv. Massai was more sensitive to irrigation with fish farming effluent than thoseof the cultivars Tanzania and Mombasa.