Weed Invasion in New Stands of Alfalfa Seeded with Perennial Forage Grasses and an Oat Companion Crop
- Eric Spandl,
- James J. Kells and
- Oran B. Hesterman
Weed invasion in alfalfa (Medicago sativa L.) may be reduced by seeding with a perennial forage grass. Our objectives were to determine if any of four perennial forage grasses influenced weed invasion when seeded with alfalfa, with and without an oat companion, and if this reduction was consistent among harvests and throughout the duration of the stand. Alfalfa was seeded alone and in binary mixtures with smooth bromegrass (Bromus inermis Leysser), orchardgrass (Dactylis glomerata L.), timothy (Phleum pratense L.), or Kentucky bluegrass (Poa pratensis L.). All forages were seeded with and without an oat (Avena sativa L.) companion crop in May of 1993 and 1994. Seeding grasses with alfalfa occasionally reduced weed yield in the first 2 yr of the stand. Weed density was not influenced by the perennial grasses in the seeding year. In the third year, mixtures containing orchardgrass or Kentucky bluegrass reduced weed yields by 20 to 130 kg ha−1 in three of four harvests and dandelion (Taraxacum officinale Wigg.) density up to 5.4 plants m2 (71%). Bromegrass and timothy did not persist with four annual harvests. Seeding the mixtures with an oat companion reduced weed and perennial grass yield in the seeding year and perennial grass yield the fo|lowing year. As a result, dandelion density in the third year was 2.6 plants m2 (70%) greater in mixtures established with oat than without oat. Including perennial forage grasses can be effective at reducing weed invasion by the third year of the stand if grass is maintained as a major component of the forage.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .