Spring Alfalfa Plant Evaluation
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.
Irrigated Annual Forage Options
Whether it is the possibility of drought or loss of pasture because of wildfire, some producers are considering using irrigated annual forages to bolster their grazing or hay supplies.
For spring or cool-season annual forages, we are in the planting period of late March to early April. Soil temperatures this year are currently well above the recommended 42- to 45-degree range. Oats are probably the most common cool-season annual forage planted in Nebraska. However, spring triticale or spring barley are two other small grain options that have been found to perform similarly to oats in terms of forage yield and quality.
Also similar is the number of days until ready to begin grazing or hay, so the different species could be mixed if desired. One could look at seed cost of the different species before making a decision.
With the early spring planting date of the cool-season annuals, grazing can typically begin around the third or fourth week of May and last into early July. Haying usually take place around the third week of June.
Following the cool-season forage, a warm-season annual such as sudangrass, sorghum-sudan hybrids, forage sorghum (which we often call cane or sorgo), foxtail millet or pearl millet could be planted. Systems can also be put together where different acres of cool- and warm-season annuals are planted to create the continuous availability of grazable forage from late spring through fall.
Remember to consider the herbicides that may have been used on a field the previous year. Some herbicides may have long residuals that could hinder establishment even into this spring.
