If an alfalfa field is hit by hail, the amount of damage and the crop’s growth stage should help determine when to cut, says Bruce Anderson, University of Nebraska Extension forage agronomist.
Alfalfa growth normally originates from the tip of the stem, Anderson explains. If the tip is removed – by mowing, grazing or hail – stem growth ceases and regrowth must begin. Regrowth comes from the crown if the entire top of the plant has been cut off. But when lower branches and leaves still remain on the stem, as usually is the case after hail, new growth often develops slowly from axillary buds near stem branches. Regrowth rates can be very low if many plants in the field were damaged.
“You can speed up recovery of alfalfa by harvesting the field as soon as possible after hail to encourage crown regrowth rather than axillary regrowth,” says Anderson. “Deciding when is your biggest challenge.”
Cut immediately if plants have reached late bud stage and more than 25% of plant tips are broken, he advises. For plants within two weeks of harvest, cut if one-half or more of the growing tips are injured or if most plants are lodged. And harvest or shred anytime more than two-thirds of the plant tips are broken, regardless of how much growth exists, unless the hail was so severe that only stubble remains anyway. After cutting, delay your next harvest to allow plants extra time to recover from the extra stress.
“To cut or not to cut, that is the question,” says Anderson. “And your answer will affect growth rates of this, and your next, cutting.”