This study evaluated the growth, forage production, soil water balance, water indices, biological efficiency and competitive capacity of forage cactus and maize in monoculture and intercropping, with or without mulch. The experiment was conducted in Serra Talhada, Pernambuco, Brazil, using the cactus clone 'Orelha de Elefante Mexicana' (OEM) and the hybrid maize 'Feroz VIP'. The first and second forage cactus cycles were from October 2020 to August 2021 and August 2021 to June 2022, respectively. Each forage cactus cycle was followed by two maize cycles. Treatments were arranged in randomized blocks with four replicates, comprising: (i) single maize and cactus without ground cover; (ii) single maize and cactus with ground cover; (iii) intercropping cactus-maize without ground cover; and (iv) intercropping cactus-maize with ground cover. Biometric and biomass assessments quantified morphophysiological indices, phenology, cutting time, biological efficiency and competitive capacity, while soil moisture and water balance were monitored. The mulched system achieved yields of similar to 19.0 and 12.41 Mg ha(-1) dry matter, and net incomes of US$ 1908 and 1914, evidencing its economic superiority. Water productivity and evapotranspiration efficiency were also improved under cover. Combined cultivation of forage cactus and maize is recommended due to increased production, profitability and sustainability in semi-arid environments.