Establishment of Corn in Rotation with Alfalfa and Rye: Influence of Grazing, Tillage, and Herbicides

Abstract

AbstractIntegrating livestock into crop rotations offers alternatives for grazing and crop management. Grazing, tillage, and herbicides were evaluated in a randomized block design with four replications for transition from alfalfa (Medicago sativa L.) to corn (Zea mays L.). For the control (T1), alfalfa was overseeded with rye (Secale cereale L.) in October, and corn was no‐till established in early May. For alternative treatments, alfalfa was grazed by cattle (Bos taurus) from July until October. Treatments were: T2, disking prior to rye planting, grazing rye for 12.5 d prior to corn planting, with dicamba (3,6‐dichloro‐2‐methoxybenzoic acid) applied after corn planting; T3, no spring grazing, with glyphosate [N‐(phosphonomethyl)glycine] applied before corn planting; T4, same as T3 plus grazing rye for 1.8 d in early spring; T5, autumn application of glyphosate to alfalfa before planting a rye‐hairy vetch (Vicia villosa Roth) cover crop; and T6, autumn disking before planting rye‐hairy vetch with no herbicides used. System T2 increased suppression of alfalfa and corn plant populations compared with shorter grazing periods. System T4 increased corn plant populations compared with no spring grazing (T3; 3.5 vs. 3.0 plants m−1). Autumn disking (T6) generally provided less control of alfalfa than autumn application of glyphosate (T5). Applying glyphosate before corn planting (T3 and T4) improved corn populations and growth, compared with autumn glyphosate or disking (T5 and T6), and resulted in corn forage yield (23 Mg ha−1) similar to conventional no‐till establishment (T1; 22 Mg ha−1). Herbicides completely killed alfalfa, but grazing alfalfa and rye reduced alfalfa persistence. Grazing could provide benefits to corn production systems while providing forage for cattle.