Heat stress is severely affecting alfalfa seedings, yet growers can help make sure new stands survive, suggests University of Nebraska Extension forage specialist Bruce Anderson.
“Alfalfa seedlings are tough. Despite their slow rate of growth and tender appearance, many of them manage to survive stressful conditions and become productive haymakers,” he says.
“But because of the extended heat and dry weather, alfalfa seedlings are experiencing more stress than usual, so anything you can do to reduce stress and competition will help.”
He advises beginning with weed control. Weeds use moisture and intercept light, which are two critical needs of seedlings. Herbicides are a good control option if weeds aren’t large and are growing actively. Otherwise, clipping may be necessary. If you must clip, be careful not to smother seedlings with clippings. Also leave a tall stubble so seedlings, because of the sudden change in their micro-environment, don’t go into shock after clipping.
Be sure to scout for insects. Leafhoppers, aphids, grasshoppers and other insects cause extra problems during stressful weather. Timely insecticide application or mowing is more important than ever.
During drought, don’t harvest until seedlings have had 70 days or more of growth, he recommends. “They probably will be in full bloom; but they also will have a pretty good root system to gather whatever moisture they can or grow quickly after it rains. They may be short, but at today’s hay prices, it doesn’t take much to pay harvest costs.”