The stress of forage season is officially underway for farmers across the country. With alfalfa being one of the most important forage crops on the farm and feed prices on the rise, it’s critical to ensure your stand is harvested in a timely manner to maximize quality while preserving quantity. But when is alfalfa ready to cut? The Pennsylvania State University dairy extension team provides the following tips to consider:
Harvesting Established Stands
What’s Your Crop’s Life Expectancy? - The intensity of cutting management (the number of cuttings made per year) should be based on the desired quality and life expectancy of the crop. If the goal is to have a long-lived stand, then a longer cutting interval should be considered. If the crop is being grown under a short rotation (three years or less), then more cuttings may be desirable to maximize forage quality.
First Cutting - The first cutting in the spring can be made when the crop is in the bud to early-bloom stage. During the spring there is generally limited environmental stress and the alfalfa crop can normally tolerate early cutting. Harvesting at the bud stage has allowed producers to get more cuttings per year, increase their production, and improve the quality of their forage. However, in order to cut this early, there should be optimum levels of soil pH, phosphorus, and potassium, and plants should be allowed to reach the first- bloom stage at least once during the year.
Second Through Fourth Cutting - Cuttings made during the summer (second, third, and fourth cuttings) should be made when the crop is in the bud to early-bloom stage of development. Some producers are attempting to cut when the alfalfa is even less mature than recommended. A cutting interval that is consistently shorter than thirty days can be extremely stressful to the stand because energy reserves cannot be stored in the taproots and crowns. Low energy reserves lead not only to poor regrowth (which results in poor yields) but also to an actual loss of stand--sometimes in one year.
Monitor Crop Stress – Alfalfa generally maintains production during short periods of dry weather because of its deep and extensive root system. However, during extended periods of dry weather alfalfa growth is reduced and flowering may occur on short, stunted plants. Cutting during these stressful periods does not weaken alfalfa plants or cause stand reductions. If there is adequate late summer or fall growth, after the alfalfa plants have been drought stressed during the summer, an additional harvest can be made in the fall with less risk of stand loss than if the alfalfa was not drought stressed.
New Stands
First Cutting - During the year of establishment, seedlings need a high level of energy reserves to persist through the winter. For spring seedings that are made without a companion crop, two harvests can generally be made the first year, provided there are adequate rainfall and optimum levels of soil nutrients. The first harvest can be made before flowers begin to appear, but waiting for the alfalfa to flower will ensure greater energy reserves in the roots. Alfalfa will generally reach this stage of development between 60 and 70 days after emergence.
Second Cutting - The second harvest should either be made before September 1, to ensure an adequate buildup of energy reserves for winter or be delayed until after the first killing frost (24 °F) in the fall or after mid-October. Occasionally, when the second harvest is made before September and there are good fall growing conditions, a third harvest may be made, but not until there is a definite killing frost. When mid-October or later harvests are made, a high stubble (6 inches) should be left for ground cover to protect the crowns and to catch snow for added insulation.
Companion Crop Alfalfa - Spring seedings which are made with a companion crop such as oats are usually harvested for the first time based on the maturity of the companion crop. Alfalfa harvests made after the companion crop has been harvested should follow the same guidelines as for alfalfa when seeded without a companion crop.
Fall Seeded Crop - The spring harvest of a fall-seeded alfalfa crop should be based on plant development and vigor. If the alfalfa plants look vigorous and the roots are well developed, spring cutting can be made at bud to early bloom. If plants are small and poorly developed, it is best to wait until mid-bloom before harvesting.
