Legume Establishment in Grass Sods Using Minimum-Tillage Seeding Techniques without Herbicide Application: Forage Yield and Quality

Seedings of forages can now be made directly into existing vegetation following herbicide application. Herbicides, however, are expensive and may destroy desirable vegetation. Three field experiments were conducted on a Paxton fine sandy loam soil (coarse-loamy, mixed, mesic Typic Dystrochrepts) to evaluate minimum-tillage establishment of legumes in grass sods without herbicide application and to evaluate subsequent changes in forage quality. In Exp. I, alfalfa (Medicago sativa L.), birdsfoot trefoil (Lotus corniculatus L.), and crownvetch (Coronilla varia L.) were seeded into orchardgrass (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.), smooth bromegrass (Bromus inermis Leyss.), and timothy (Phleum pratense L.) sods. Harvests were taken in 1975 through 1978 and samples obtained in 1977 and 1978 were analyzed for in vitro dry matter disappearance (IVDMD), crude protein, and mineral content. Alfalfa and birdsfoot trefoil establishment was most successful in timothy and smooth bromegrass and least successful in orchardgrass. Crownvetch failed to establish. Alfalfa mixtures produced the most dry matter, digestible dry matter, and crude protein in 1977 and 1978. Winter survival was greatest for legumes seeded in tall fescue. Experiments II and III were conducted on sites where soil pH was 6.4 and 5.6, respectively. Birdsfoot trefoil, red clover (Trifolium pratense L.), and crownvetch were directly seeded into a mixed grass-forb sod. Vegetation was mowed for 8 weeks after seeding at either 2- or 4-week intervals. Crownvetch failed to establish. Mowing frequency after seeding had little effect on legume establishment. Red clover seedings increased yields of crude protein in 1977 and digestible dry matter in 1977 and 1978. Birdsfoot trefoil did not increase digestible dry matter yields, compared to the control, until 1979 on the timed soil but increased digestible dry matter yields in 1978 on the initially unlimed soil. Results indicate that alfalfa, birdsfoot trefoil, and red clover may be successfully direct seeded into certain grass sods that have not been suppressed using herbicides.