The Water Efficiency and Productivity of Forage Maize (Zea mays L.) in a Semi-Arid Region Under Different Humidity, Nitrogen, and Substrate Levels

The Lagunera Region, located in northern Mexico, is home to the country’s most important dairy basin, situated in a semi-arid environment. In this region, forage corn (Zea mays L.) is the main input in dairy cattle feed. In this context, optimizing water use and nitrogen nutrition is a priority to ensure the sustainability of this activity. The main objective of this study was to evaluate the productivity and water use efficiency of forage corn under different humidity, nitrogen, and substrate type levels. A randomized block design with sub-subdivided plots was used. The larger plot contained two usable moisture levels (80 and 50%); the subplots were assigned according to three nitrogen levels: 13.6 (N1), 6.8 (N2), and control 0.35 (N3) NO3 mmol·L−1; the sub-subplots were assigned based on two substrates: sand and a mixture (MI) of sand, perlite, and peat moss. The results showed significant triple interactions (p < 0.05) in the root volume traits, where nitrogen played a determining role, as well as double interactions (Nutrition*Substrate) for all vegetative and radicle production variables and water use efficiency. Principal components analysis explained 91.4% of the total observed variation, where basal diameter had the vector with the highest load value. Cluster analysis identified that the main discriminant factor was nutrition. It is concluded that usable moisture levels up to 50% with 6.8 mmol·L−1 of NO3 show acceptable levels of vegetative production and root volume in forage corn. These results suggest the possibility of reducing water and nitrogen fertilizer consumption without compromising yield, with significant economic and environmental benefits for agriculture in arid and semi-arid regions.