By Ben Beckman
As temperatures begin to rise, don’t forget to take a bit of time to assess alfalfa stand health going into this year’s growing season. Snow cover over the winter helped insulate plants from extreme temperatures, but exposed plants, older stands or late harvested alfalfa still have a potential for winter kill.
Even before plants begin to green up, individual plant assessments can be done. While assessment before green-up occurs may seem a bit preemptive, pre-scouting now can focus scouting efforts to problem areas later on when time becomes precious during spring planting.
- Dig up four to five random plants per 20 acres, being sure to get the crown and a good portion of the tap root (around 6 inches at least). Split the root and crown open. A healthy plant will be white and firm, while winter-damaged taproots will be yellow to brown and stringy. Yield will begin to be impacted when damage is greater than 30% of the total root/crown area.
- Look for alive, intact basal buds at the crown of the plant. Buds formed last fall will start growth sooner and boost first cutting yields. A lack of basal buds doesn’t mean that the plant won’t recover, but first cuttings may be smaller.
- If plants have begun growth, look at where it is occurring on the crown. Healthy plants will have growth fully throughout the crown while damaged plants will often have asymmetrical growth with more stems on one side than the other.
If more than 30% of the plants assessed have significant damage, yield for the upcoming year may be impacted. Options like interseeding perennial grasses, seeding a warm-season forage crop after the first harvest, or terminating the stand may need to be considered.
Source : unl.edu