The objective was to determine growth, biomass production, water use efficiency, and the chemical characteristics of sorghum (BRS Ponta Negra), irrigated with different depths of brackish water and fertilized with levels of organic matter, in two cultivation cycles. The experiment was a 4 × 4 factorial randomized block design, consisting of four levels of irrigation with brackish water (25, 50, 75, and 100% evapotranspiration), 4 levels of organic matter (0, 15, 30, and 45 t/ha), with three repetitions. The brackish water levels promoted an isolated effect for stem diameter, number and percentage of leaves and number and percentage of dead leaves (P < .05) in the first cut. For the second cut, there was effect of brackish water on the number of leaves, number of dead leaves, percentage of dead material, water use efficiency, dry matter content, and hemicellulose content (P < .05). Regarding the applied organic matter levels, there was an isolated effect of treatments on plant height, stem diameter and fresh matter production (P < .05) in the first cut of sorghum. The application of organic matter influences the growth and production variables. The greater amount of brackish water can negatively affect growth variables, water use efficiency, and chemical composition of sorghum plants.