The Influence Of Seeding Rate On Plant Population Yield And Quality Of Two Alfalfa Medicago Sativa L Varieties

A field study was conducted in the Willamette Valley near Corvallis, Oregon, to determine the influence of seedling rate, drill row spacing, grass association, and variety on the yield of dry matter and quality (crude protein content and leafiness) of alfalfa. Treatments included seeding rates of 7.5, 10, 15 and 20 pounds per acre in various combinations with row spacings of 3, 6 and 12 inches. Orchardgrass (Dactvlis glomerata L.) was included tn three treatments. Complete data were obtained for three harvests and yield data only for an aftermath harvest. Alfalfa varieties were Vernal and DuPuits. Plant population and stem numbers per unit area increased with increasing seeding rates and with closer row spacing, but stem size, dry weight of the stems, leafiness and crude protein were not affected by seeding rate or row spacing. Grass grown in association with alfalfa did not influence any of the characteristics studied except for an increase in stem size at second harvest and increased protein content of the alfalfa at first harvest. Vernal and DuPuits yielded the same weight of dry material for the season. Vernal maintained a higher plant population, more stems per square foot at each harvest and a higher percentage of leaves than DuPuits. Stem size and weight and crude protein content of whole plants was higher in DuPuits than in Vernal. Both varieties decreased in yield, plant population, stem size and stem weight with each successive cutting. Stem number per square foot and per plant increased with each successive cutting. It was concluded that seedling rates from 7.5 to 20 pounds per acre and row spacings up to 12 inches had very little influence on quantity and quality of alfalfa hay production.