To enhance livestock productivity in dry seasons and drought areas, deficit irrigation, fertilizers, and water-efficient forage grasses become crucial in agriculture. The experiment evaluated the effects of different deficit irrigation levels and fertilizer rates on the productivity and nutritional quality of forage grasses at the Robit Bata site in the 2020/21 and 2021/22 study periods. The experiment consisted of three types of forage grasses, desho grass (arekadzf 590), brachiaria decumbens (ILRI 10871), and brachiaria mutica (ILRI 18659), three irrigation levels I100 (100% of the total available soil water), I80 and I60, and three fertilizer type and rates (Manure 30t/ha, 100kg/ha Urea and 300kg/ha Urea) arranged in a split-split plot with 3×3×3 with three replications. The main plots were assigned to the irrigation treatments, while the subplots and sub-sub plots were assigned to fertilizer and forage varieties respectively. The growth, yield, and nutritional quality parameters were collected and organized by MS- Excel and subjected to ANOVA analysis using R software's general linear model procedure, at a significance level of 5%. The use of urea at a rate of 300 kg/ha had 44 and 47% increments in dry matter yield compared with 100kg/ha and manure 30t/ha., as well as the highest water use efficiency and water productivity of the grasses were obtained at urea 300kg/ha. Dry matter yield, crude protein yield, and metabolized energy did not significantly differ between I80 and I100 irrigation levels for forage grasses. Likewise, there were no significant differences in water use efficiency and productivity between I80 and I60 irrigation levels. However, a significant difference in dry matter yield was observed between I80 and I60. Brachiaria mutica exhibited 37% and 118% greater dry matter yield and 22% and 100% superior in water use efficiency with comparison to Brachiaria decumbens and Desho grass, respectively. Therefore, the recommendation is to use brachiaria mutica (ILRI 18659) with I80 irrigation level and 300kg/ha urea application, demonstrated to be the most favorable in terms of forage productivity, water use efficiency, and nutritional quality under experimental conditions. A more detailed socioeconomic analysis should be conducted to further validate the adaptability and social acceptability of this forage production system. Keywords: Livestock, Forage, deficit irrigation, full irrigation, fertilizer response, water use efficiency, nutritional quality.