Interference Between Oats and Alfalfa in Mixed Seedings1
- R. L. Nielsen,
- D. D. Stuthman and
- D. K. Barnes2
Oats (Avena sativa L.) are frequently used as a companion crop for the establishment of alfalfa (Medicago sativa L.) in the Upper Midwest of the United States. Unpublished observations from research in Minnesota suggested that some level of interference might be occurring between the two species. The objectives of this research were to determine if companion cropping affected oat grain yield and subsequent alfalfa forage yield under field conditions and to identify cultivar combinations that exhibited either interference or tolerance for each other.
Five oat cultivars (‘Multiline E-77’, ‘Froker’, ‘Lang’, ‘Noble’, and ‘Stout’) and five alfalfa cultivars (‘Agate’, ‘Cody’, ‘DuPuits’, ‘Iroquois’, and ‘Washoe’) plus an experimental alfalfa population (MN Allelopathy) selected or its allelopathic potential on maize (Zea mays L.) were seeded in a split-split plot design at two locations in 1978 and three locations in 1979. Oats and alfalfa were harvested for grain and for second-year forage production, respectively.
Oat grain yield changes across all oat and alfalfa cultivars caused by alfalfa ranged from a 1.56 quintals/ha reduction at St. Paul, Minnesota, to a 1.65 quintals/ha increase at Waseca, Minnesota. Alfalfa yield in the year after establishment was reduced by oats by 0.44 metric ton/ha/cutting at Rosemount, Minnesota, and 0.19 metric ton/ha/cutting at Waseca, Minnesota. Across all environments and oat cultivars, only the MN Allelopathy alfalfa selection significantly reduced oat grain yield. Significant grain yield reductions were also observed in three oat-alfalfa cultivar combinations: Noble/Cody, Stout/MN Allelopathy, and Lang/Iroquois. The results indicated that interference existed between some oat and alfalfa combinations in some companion cropping systems.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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