Maize (Zea mays L.) is one of the main cereal crops grown around the world and is widely used as food, feed and raw material in various industries. However, the crop is sensitive to weather conditions, and this causes large variations in yield between crop seasons. Suboptimal irrigation can be used to secure reasonable yields with increased water productivity. For maize grown offseason in the Cerrado biome of Brazil, there is little knowledge about the benefits of suboptimal irrigation. This study was designed to evaluate the effect of different irrigation amounts and two Brachiaria cultivars intercropped with maize on maize grain yield, biomass production for silage and water productivity in the second crop season. The study was conducted at Embrapa Milho e Sorgo Experimental Station, Sete Lagoas, MG, Brazil, in 2018 and 2019. Six irrigation levels were obtained by using a line-source sprinkler irrigation system. The irrigation levels used ranged from 94% to 11% of the cumulative reference evapotranspiration (ET₀) in 2018, and from 90% to 34% of ET₀ in 2019. Suboptimal irrigation above a certain level did not cause a significant decrease in silage biomass (59% and 71% of the ET₀, in 2018 and 2019, respectively) and grain productivity (48% and 60% of the ET₀, in 2018 and 2019, respectively). Additionally, there was an increase in crop water productivity and irrigation water productivity, for biomass of both silage and grains. The results demonstrate the potential of suboptimal irrigation as a strategy to reduce water resource usage while maintaining acceptable productivity levels.

玉米（Zea mays L.）是世界范围内主要的谷物作物之一，被广泛用作食品，饲料和各种行业的原材料。然而，作物对天气条件很敏感，这会导致作物季节之间的产量差异很大。次优灌溉可用于通过提高水生产力来确保合理的产量。对于在巴西塞拉多生物群落种植的淡季玉米，人们对次优灌溉的好处知之甚少。本研究旨在评估不同灌水量和两种臂形草的效果。与玉米间作的品种对玉米籽粒产量、青贮饲料的生物质产量和第二季的水生产力都有影响。该研究于 2018 年和 2019 年在巴西 MG Sete Lagoas 的 Embrapa Milho e Sorgo 实验站进行。 通过使用线源喷灌系统获得了六个灌溉水平。使用的灌溉水平为 2018 年累积参考蒸散量 (ET ₀ ) 的94% 至 11%，2019 年为 ET _{0 的}90% 至 34%。高于一定水平的次优灌溉并未导致青贮饲料显着减少生物量（分别为 ET _{0 的}59% 和 71% ，2018 年和 2019 年）和粮食生产力（ET _{0 的}48% 和 60%，分别在 2018 年和 2019 年）。此外，对于青贮饲料和谷物的生物量而言，作物用水生产率和灌溉用水生产率都有所提高。结果证明了次优灌溉作为减少水资源使用同时保持可接受的生产力水平的策略的潜力。