Winters in the Intermountain West can be long and harsh. The extreme weather conditions often affect fall-planted annual crops and even perennial crops, like alfalfa. As the snow melts and plants start to grow, you can evaluate your alfalfa stand to determine its condition and a plan of action. By early May, you should have adequate growth to evaluate your alfalfa stand's overall health, and still have a few weeks to implement your plan before harvesting your first cutting.
Evaluating Alfalfa Crop Stands
Plant Health
When evaluating the health and productivity of your alfalfa stands, dig up three to four representative plants. First, count the number of stems on each plant and evaluate them for size and symmetry. You should have ten or more stems per plant that are similar in size. Having less than eight stems on each plant indicates that the stand is in decline.
Next, you want to evaluate the roots of the plants. Cut the root lengthwise, looking for rot or discoloration. Healthy roots will be firm with a white or slightly yellow color. A diseased root will have dark brown areas extending down the center of the taproot.
Field Health
After evaluating the individual plants, you should do a stem count on the overall field. The easiest way is to create a one-foot square out of PVC pipe or small pieces of wood that you can toss into the alfalfa stand. Randomly toss the square and count the number of stems inside that area. Do this four to five times throughout the field to get a good sample size and average your counts.
If your average is greater than 54 stems, you have a healthy stand and can expect no yield loss. If your average is below 54, you are likely to see yield loss, and if your average is below 40 stems per square foot, you should consider replacing the stand.
Managing Low-Producing Alfalfa Stands
If your evaluation reveals that the stand needs replacing due to disease, winterkill, or natural thinning, you have multiple options depending on the type of alfalfa you grow.
Conventional Alfalfa Crop (NOT Roundup Ready)
If you planted conventional alfalfa (not Roundup Ready), you can kill the stand and plant back into another crop, such as a 3-way forage grain or any number of grass crops. You can either spray the field immediately and replant as soon as you work the soil or, because you are only a few weeks away from harvesting your first cutting, you can wait until it is time to cut and then spray with Roundup.
The Roundup label allows you to spray and harvest the crop, work the soil, and replant all within a short time. You can still feed the hay to livestock or sell it for feed without issues from the Roundup. Please consult your local IFA crop advisor for exact details and requirements for this procedure.
Companion Crops
Another option when dealing with a thinning or weak stand is to thicken the stand with a companion crop, allowing you to finish the crop year with your alfalfa stand and use the companion crop to increase yields. If you planted Roundup Ready alfalfa, this is the ideal option because you cannot kill it using Roundup. Here are a few planting suggestions to thicken up your stand:
Sudan Grass
Sudan grass can be inter-seeded with alfalfa stands and rapidly establishes in the summer heat, providing quality forage blended with the alfalfa’s nutrient quality. Sudan grass will terminate in the fall with the first killing frost, allowing time for planting fall-seeded rotational crops.
Sorghum Sudan
Sorghum Sudan is great for chopping or baling as a companion crop and provides significant yield in the summer heat. Sorghum Sudan and Sudan grass are susceptible to prussic acid buildup, which can be fatal to livestock. Please always consult a crop advisor if planting either of these crops to understand best harvesting practices.
Pearl Millet
Pearl Millet is a reliable, leafy grass that grows quickly in the summer heat and does not contain the prussic acid and the short-term issues related to Sorghum and Sudan plants.
Foxtail Millet
Foxtail Millet produces significant forage for a single cutting in areas with limited water at the end of the growing season. If water is unpredictable or you know it will be short, planting Foxtail Millet is a good option to get one more cutting before replanting.
Timothy Grass
Timothy Grass is great for inter-seeding in alfalfa stands and establishes rapidly with high production. Timothy grass is especially good in areas where your harvest window is longer between cuttings (42-45 days apart). This palatable, nutritious grass is a valuable companion crop if your customer base is the horse market.
Teff Grass
Teff grass produces soft, leafy, high-quality hay ideal for the horse market. It has good forage production through the summer months and terminates in the first killing frost of the fall, like other summer annuals.
Italian Ryegrass
Italian Ryegrass is another leafy, high-quality grass that is a great companion to alfalfa in areas with adequate water. It requires irrigation, so avoid planting in areas with short water. Italian Ryegrass produces quality forage in good volumes through the summer, with vernalization occurring over the following winter. The crop then enters the reproductive part of its life cycle, allowing for one final spring cutting that terminates the crop.
Orchard Grass
Orchard Grass is a perennial solution that can extend the life of an alfalfa stand several years if you are looking for a solution to keep the stand a little longer. Planting Orchard Grass produces a monoculture with more grass and less alfalfa each subsequent year.
Fescue
Much like orchard grass, Fescue is another perennial solution to extend the life of a stand. It produces quality forage for several years as a companion to thinning alfalfa. Fescue can be problematic for pregnant mares, so consult a veterinarian before feeding horses.
Growing Productive Alfalfa Stands with IFA
Improving production in your alfalfa stands means better yields and a quality product. These solutions apply to hay growers and cattlemen who grow their own forage and graze their fields in the fall. Again, you want to be cautious with Sorghum Sudan grasses to avoid prussic acid poisoning, but these planting options are grazeable.
IFA appreciates our co-op members, and we look forward to working with you throughout the growing season. If you have any questions, please contact your local IFA crop advisor for help deciding the best solution to an early thinning alfalfa stand.
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Written by Tony Carlile , CCA & IFA Agronomy Salesman, and originally published in the IFA Cooperator magazine (vol. 90, no. 2) Summer 2024.