Management and productivity of corn–alfalfa intercropping systems in the southeastern United States

Abstract Corn ( Zea mays L.) is widely used in the southeastern U.S., but its low protein concentration and drought susceptibility often limit productivity and nutritive value in corn silage systems for ruminant livestock. Intercropping forages into corn‐based systems may improve nutritive value and system resilience. A two‐year field study in Tennessee evaluated herbage mass (HM), botanical composition, nutritive value, and corn silage yield in four systems: alfalfa ( Medicago sativa L.) alone (AA), corn alone (CA), alfalfa intercropped with corn (AC), and alfalfa intercropped with corn and crabgrass ( Digitaria ciliaris L.) (ACC). Herbage mass was influenced by year but not by cropping system, averaging 2556 lbs dry matter (DM) acre −1 . Alfalfa persistence declined over time, particularly when crabgrass was included, while crabgrass proportion increased under drier conditions. Crude protein was highest in alfalfa‐based systems but declined as alfalfa persistence decreased. Crabgrass inclusion improved fiber digestibility and helped maintain nutritive value when alfalfa declined. Corn silage yield was greater in 2023 than in 2024; CA outyielded intercropped systems in 2023, whereas no yield differences were observed in 2024 (4817 lbs DM acre −1 ). Under Middle Tennessee conditions, alfalfa‐corn intercropping alone is unlikely to improve productivity due to the limited alfalfa persistence during hot, dry summers, although crabgrass can help maintain forage nutritive value and productivity. Irrigation and targeted management may be necessary to maintain long‐term system benefits.