The adequate management of irrigation with brackish water associated with balanced nutrition with potassium (K) should be investigated to reduce the deleterious effects of salt stress and increase the yield of sweet sorghum, which is suitable for forage exploration and in the biofuel industry. This investigation evaluated the effects of irrigation depth of brackish water and different doses of potassium on the growth and production of sweet sorghum, with the aim of obtaining better performance of this crop under different management of these inputs in the semi-arid region of Pernambuco, Brazil. Thus, the growth and yield of sweet sorghum were investigated under five irrigation depths (ID1 = 222, ID2 = 388, ID3 = 554, ID4 = 720, and ID5 = 886 mm) with brackish water and five K2O doses (0, 10, 20, 30, and 40 kg ha-1) in a randomized complete block design. Plant height, stem diameter, fresh mass of the stem, leaves, panicle, and total fresh mass were evaluated in this investigation. Total fresh mass exhibited a surface response, with the highest estimated value (39.10 Mg ha-1) observed under an irrigation depth of 760 mm combined with a K2O application rate of 40 kg ha-1.The study of different irrigation depths and their interaction with doses of K2O indicates the requirements for a greater supply of nutrients and water to sweet sorghum in the semi-arid region, enabling a more appropriate irrigation and nutrition regime for the crop in the region.