Response of Four Alfalfa Cultivars to Fall Harvesting in the Southern Plains

Alfalfa (Medicago sativa L.) often makes sufficient fall growth in the Southern Plains of the USA to merit harvesting. The objectives of this research were to evaluate the effect of repeated fall harvesting between mid‐September and late November for several years on stand persistence and forage yields on a stand established in the spring of 1980, and to determine if there are differences among alfalfa cultivars with varying types of pest resistance and winter dormancy. Starting in 1980, 12 fall harvest treatments were imposed on spring established stands of ‘Arc’, ‘Buffalo’, ‘Dawson’, and ‘Riley’ cultivars and repeated in 1981 and 1982. Forage was harvested at 10 to 25% bloom for uniform harvests prior to imposing fall harvest treatments in 1980,1981, and 1982. Forage yields were calculated for the duration of the study and total nonstructural carbohydrate (TNC) reserves were measured in alfalfa roots dug after the initial killing freeze of each fall. Some yield reductions resulted with Arc at first harvest the year following fall harvesting of spring seeded stands. The long‐term effects of fall harvesting did hot appear critical, however, since other uniform harvests and total forage production during the course of the study were not significantly affected. Root carbohydrate concentrations were not affected by fall harvest treatments in any year. Plant and stem densities of the cultivars declined during the study with some differences among cultivars; however, there were no differences in these measurements which could be attributed to fall harvest management.