Sod‐Seeding and Grazing Effects on Alfalfa Weevils, Weeds, and Forage Yields in Established Alfalfa

Abstract

Alfalfa (Medicago sativa L.) hay production for dairy and equine industries is a profitable enterprise in the Great Plains. However, as stands thin, forage production decreases and weeds increase, resulting in decreased returns. The objective of this research was to determine if alternative management strategies using October sod seeding plus March grazing could be utilized to increase forage production and control pests. Experiments were conducted at four locations in central Oklahoma from 1998–2000. Two ungrazed treatments (with and without pesticides) were compared with three treatments without pesticides but grazed by cattle in March. The three grazing treatments included: no sod seed, ryegrass (Lolium multiflorum Lam.) sod‐seeded in October, and wheat (Triticum aestivum L.) sod‐seeded in October. Grazing by cattle reduced alfalfa weevil (Hypera postica Gyllenhal) larval populations as effectively as insecticide application. In thin stands (<200 stems m−2), total forage yields were increased with alfalfa–grass mixtures by an average of 2.7 kg ha−1. However, alfalfa yields were decreased 0.9 kg ha−1 with sod‐seeded ryegrass (P = 0.05). In thin stands, sod‐seeded grass treatments were more effective at weed suppression than a herbicide treatment. Net returns from cool‐season forage production increased with sod seeding plus March grazing compared with net returns using conventional haying methods. In thin stands (<200 stems m−2), sod seeding of ryegrass or wheat plus March grazing provided greater net returns ($175 ha−1) than conventional practice of using pesticides and haying. In full stands (>250 stems m−2), net returns from conventional alfalfa management (using pesticides and only haying) were comparable to October sod seed plus March grazing treatments.