NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665
March 30, 2000
Alfalfa producers located in areas of North Dakota that received snow along with the cold temperatures during the first full week of March probably don't have to worry about the condition of their crops. But producers whose alfalfa didn't benefit from that protective blanket of snow may be looking at some potentially serious instances of winter injury and perhaps even winter kill, says a forage specialist at North Dakota State University.
"The alfalfa in the north central and northeastern parts of the state had broken dormancy and initiated growth of from 1 to 2 inches," says Dwain Meyer, NDSU plant sciences professor. "We know for a fact that those alfalfa stems which initiated growth have burned off. What we don't know is if those plants still have any buds left that can initiate more new growth."
Alfalfa stands that are 1 year old are more likely to have survived the sub-freezing temperatures than are 3-year-old stands. Meyer says producers concerned about their alfalfa fields should dig root samples from three or four locations in each suspect field.
Healthy roots should be white and firm. A tap root with a black streak running down its center indicates a plant infected by Fusarium root rot, a condition generally unrelated to winter injury or winter kill. Meyer says Fusarium root rot is prevalent in alfalfa fields throughout North Dakota, and plants infected with the disease are still capable of growing adequately, but vigor has been compromised. A tap root that is yellowish in color with a soft, cork-like texture is dead, the result of winter kill.
"If you find dead plants in several areas of a field, you've got to decide if there's going to be an adequate stand," Meyer says.
In fields where there are between 40 and 50 healthy stems per square foot, producers can expect full production. In fields with less than 20 stems per square foot--especially if this density pattern is widespread across the entire field--producers should rotate the old alfalfa ground to a cereal crop that can utilize the nitrogen produced by the alfalfa. Meyer says another option would be to no-till an annual forage such as Sudangrass or foxtail millet into the old alfalfa ground.
In alfalfa fields that have been only partially killed--those, for example, with about 30 stems per square foot--Meyer suggests seeding oats into the dead spots. He says, "No-till it an inch or an inch and a half deep. The resulting oat-alfalfa mixture will make an excellent feed for beef cows."
Cash hay producers and operators of livestock enterprises requiring alfalfa in their rations will need to re-establish their alfalfa fields in new locations. Planting a new alfalfa crop into the old alfalfa ground is risky, Meyer says, because alfalfa contains an autotoxic compound that can stunt or kill alfalfa seedlings.
"Use new ground and go for seeding-year forage," Meyer says. "With reasonable moisture, you can expect from one to two harvests during the seeding year if it's seeded the first week of May."
New-crop alfalfa will produce a harvestable stand in about 70 days, Meyer says. So producers could expect the first cutting of seeding-year alfalfa in mid-July. If significant moisture occurs either before or after that harvest, a second cutting is likely. Alfalfa producers in north central and northeastern North Dakota could expect 1.25 to 1.5 tons per acre of alfalfa from the first harvest and about 1 ton from the second with good moisture, or about 2.25 to 2.5 tons per acre in total. Under dry conditions, producers should expect no more than 1.25 tons per acre for the season.
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Source: Dwain Meyer (701) 231-8154
Editor: Dean Hulse (701) 231-6136