Alfalfa, a widely cultivated forage crop, is known for its deep root system and ability to enhance soil health. Companion planting, an agricultural practice involving growing different plants together, can significantly improve the health and productivity of alfalfa. This strategy creates a more balanced ecosystem, benefiting the primary crop in various ways.
Benefits of Companion Planting with Alfalfa
Companion planting with alfalfa offers several advantages for a robust and sustainable growing system. It improves soil health; alfalfa’s extensive root system enhances soil structure, aeration, and water infiltration. When combined with other beneficial plants, this effect is amplified, leading to better nutrient cycling and overall soil fertility.
Companion plants also provide natural pest control. They attract beneficial insects, such as ladybugs and parasitic wasps, which prey on common alfalfa pests, reducing the need for chemical interventions. Furthermore, companion crops suppress weeds, especially during alfalfa’s vulnerable establishment phase, by competing for light and nutrients. This integrated approach increases biodiversity, fostering a more resilient agricultural system.
Good Companion Plants for Alfalfa
Selecting appropriate companion plants enhances alfalfa’s growth and overall field health. Grasses like oats, wheat, rye, and orchardgrass control erosion and suppress weeds. They provide early ground cover, protecting young alfalfa seedlings from wind and water erosion, and can offer structural support. For instance, oat companion crops can reduce weed growth and improve first-cutting forage yield in the seedling year. Orchardgrass and meadow fescue are good choices for mixed alfalfa-grass hay, often increasing yields compared to pure alfalfa stands.
Flowering plants attract beneficial insects, natural predators of alfalfa pests. Dill, cilantro, and fennel, from the carrot family, attract parasitic wasps, ladybugs, and lacewings. Sweet alyssum also attracts these beneficial insects, helping manage aphid and other pest populations for a healthier alfalfa stand.
Root vegetables with deep taproots, such as carrots or parsnips, improve soil aeration and water penetration. Their deep root systems break up compacted soil layers, creating channels that allow water and air to reach deeper into the soil profile. This benefits alfalfa’s own deep roots by improving their access to moisture and nutrients.
Other legumes like clover offer ground cover benefits and attract beneficial insects. Red clover, for example, helps build soil structure and retain moisture, in addition to attracting pollinators. When planting other legumes with alfalfa, the primary benefit is their contribution to soil health and biodiversity, not nitrogen fixation for alfalfa.
Plants to Avoid with Alfalfa
Certain plants should not be grown near alfalfa due to potential negative interactions. Aggressive weeds or plants that compete heavily for resources like water, nutrients, and light can hinder alfalfa’s growth, especially during its vulnerable seedling stage, potentially reducing stand vigor and yield.
Some plants exhibit allelopathy, releasing biochemicals that inhibit the growth of nearby plants; it’s generally best to avoid those known for strong allelopathic effects. Furthermore, plants that serve as hosts for shared pests or diseases can pose a significant risk, making crop rotation with non-host crops generally recommended.
Implementing Alfalfa Companion Planting
Successful alfalfa companion planting requires careful timing. For spring-seeded alfalfa, companion crops like oats are often planted simultaneously. However, for late-summer sown alfalfa, companion crops are generally not recommended as they can compete for vital moisture when the alfalfa seedlings are establishing.
Optimal spacing prevents excessive competition while maximizing benefits. For instance, when using oat as a companion, a seeding rate of around 10 to 15 pounds per acre is recommended, lower than for a pure oat stand, to minimize competition with young alfalfa. Planting dates should prioritize alfalfa establishment.
Site preparation ensures good soil conditions for mixed planting. Ongoing management includes monitoring for competition; if the companion crop becomes too competitive, early harvesting can allow more light to reach the developing alfalfa. Avoiding nitrogen fertilizer application to alfalfa-small grain companion seedings is advised, as it can enhance the growth and competitiveness of the small grains, potentially reducing the alfalfa stand.