Alfalfa (Medicago sativa) is one of the world’s most important forage crops. This perennial flowering legume is highly valued for its exceptional nutritional quality, particularly its high protein and mineral content, making it a staple in livestock feed production. Achieving maximum yield requires careful planning and precise management, starting with foundational field conditions and continuing through cyclical harvesting.
Preparing the Field and Selecting Seed Variety
Success with alfalfa production starts long before planting by ensuring optimal soil conditions are met. Alfalfa thrives best in deep, well-drained soils, such as sandy, silt, or clay loam, which allow for the development of its extensive taproot system. The most restrictive requirement is the soil’s acidity, as alfalfa is highly sensitive; the target pH range for maximum growth is between 6.5 and 7.5. Soil testing should be performed six to twelve months prior to seeding to allow time for necessary amendments, since acidic conditions impair the plant’s ability to absorb nutrients and establish nitrogen-fixing nodules.
If the soil pH is too low, agricultural lime must be applied and incorporated into the top six inches of soil to neutralize the acidity, as lime reacts slowly. Selecting the correct seed variety depends on the local climate and the intended lifespan of the stand. Dormant varieties are preferred in colder regions for winter survival, while non-dormant types suit warmer climates that allow for more frequent cutting. Crucially, alfalfa seed must be inoculated with specific Rhizobium bacteria just before planting to ensure the formation of root nodules that fix atmospheric nitrogen, providing the plant with its own nitrogen supply.
Planting Methods and Optimal Timing
The timing and technique of planting are important for establishing a dense, uniform stand that supports high yields for multiple years. Optimal seeding generally occurs either in early spring or in late summer to early fall, depending on the climate. Spring planting is often favored in northern regions, while late summer planting is preferred where weed pressure is a concern. Successful germination requires soil temperatures around 50°F and a firm seedbed that minimizes air pockets and ensures excellent seed-to-soil contact.
Proper seeding depth is essential because the small seeds have limited energy reserves for emergence. A depth of 1/4 to 1/2 inch is recommended in heavier soils, while placement up to 3/4 inch may be necessary in sandy soils. Drilling is the preferred method for precise depth control, but broadcasting can be successful if followed immediately by a cultipacker or roller to firm the soil. Although initial soil moisture below the surface is important, planting into a dry surface soil is often advised, relying on subsequent rainfall or irrigation to trigger germination.
Essential Care and Management During Growth
Once the stand is established, ongoing management focuses on nutrient replacement, water availability, and integrated pest control to maintain stand health and productivity. Since alfalfa fixes its own nitrogen, the primary focus for fertilization shifts to phosphorus, potassium, and sulfur, which are removed in large quantities with each harvest. For example, a single ton of alfalfa hay can remove approximately 15 pounds of phosphate and 60 pounds of potash. Potassium, in particular, is directly linked to stand longevity, winter hardiness, and rapid regrowth after cutting, making its maintenance—often through fall or early spring broadcast applications—a high priority.
Irrigation is necessary in many regions, especially during dry periods, as the deep-rooted plants require about six inches of water for every ton of hay produced. New stands are vulnerable to competition, making weed control a major challenge during the first year. Control methods include pre-emergent or post-emergent herbicides, or mechanical control like timely mowing for organic production. Common insect pests, such as the alfalfa weevil, primarily damage the first cutting. Management decisions are based on scouting and economic thresholds, which may necessitate an insecticide application or a decision to harvest early.
Maximizing Yield Through Harvesting Cycles
Maximizing the lifetime yield of an alfalfa stand requires balancing the trade-off between forage quality and tonnage with each successive cutting. The first harvest is often timed to achieve the highest quality, typically occurring at the late bud stage, as quality rapidly declines as the plant matures. Subsequent cuts are usually performed on a calendar cycle, with an interval of approximately 28 to 40 days, or when new crown buds begin to appear at the base of the stem, indicating the plant has replenished its root carbohydrate reserves for regrowth.
A consistent cutting height of at least 2 to 4 inches is necessary to protect the plant’s crown, which is the growth point for the next crop, and to ensure vigorous regrowth. Cutting too low can damage the crown and reduce stand life. Cutting too high may slightly improve forage quality but will reduce overall yield. After cutting, the forage must be properly cured to reduce its moisture content before baling and storage, which prevents spoilage and minimizes the risk of fire.