Fava Beans as Cover Crops: A Comprehensive Guide

June 12, 2024 Bill Hageman

Cover cropping is an age-old agricultural practice that provides numerous benefits to the soil and the overall health of the farming ecosystem. Among the many cover crops available, fava beans (Vicia faba), also known as broad beans, stand out for their unique properties and versatility. This comprehensive guide will delve into the characteristics, benefits, and cultivation of fava beans as cover crops, highlighting various popular varieties and comparing them to other cover crops.

Introduction to Fava Beans

Fava beans, belonging to the legume family, are one of the oldest cultivated plants, with a history dating back to ancient civilizations. They are known for their ability to thrive in cool weather and their remarkable capacity to fix atmospheric nitrogen into the soil. This dual-purpose plant serves both as a nutritious food source and an effective cover crop.

Popular Varieties of Fava Beans

Several varieties of fava beans are cultivated for their specific traits, ranging from size and flavor to growth habits and climate adaptability. Here are some of the most popular varieties:

Windsor: Known for its large seeds and robust growth, Windsor fava beans are favored both for culinary uses and as a cover crop. They produce substantial biomass and enrich the soil with nitrogen. To purchase Windsor Fava Beans, click here.
Aquadulce Claudia: This variety is appreciated for its cold tolerance, making it suitable for early spring or late fall planting. It has long, slender pods with delicious seeds.
Banner: Banner fava beans are renowned for their large, flavorful seeds and high yields. They are a popular choice for both gardeners and farmers.
Superaguadulce: This variety is similar to Aquadulce Claudia but is known for its even greater cold tolerance and larger pods.
Sweet Lorane: Specifically bred for cover cropping, Sweet Lorane has smaller seeds but excels in nitrogen fixation and biomass production.

Physical Characteristics of Fava Bean Plants

Fava bean plants are easily recognizable by their distinct appearance. They grow upright, reaching heights of up to 4-5 feet. The plants have sturdy, hollow stems with pinnate leaves, each composed of multiple oval-shaped leaflets. Fava beans produce clusters of white or purplish flowers, which are followed by large, green pods. Each pod contains several large seeds, which can be green, brown, or even black, depending on the variety.

Benefits of Using Fava Beans as Cover Crops

Nitrogen Fixation: One of the most significant benefits of fava beans is their ability to fix nitrogen from the atmosphere into the soil. This is facilitated by symbiotic bacteria (Rhizobium) that form nodules on the plant roots. The nitrogen fixed in these nodules becomes available to subsequent crops, reducing the need for synthetic fertilizers.
Soil Improvement: Fava beans contribute to soil health by improving its structure and fertility. Their deep root systems break up compacted soil, enhance water infiltration, and reduce erosion. The organic matter added to the soil from decomposed fava bean plants also improves soil tilth and microbial activity.
Weed Suppression: The dense canopy formed by fava bean plants helps suppress weed growth by shading out competing weeds. This reduces the need for herbicides and mechanical weeding.
Pest and Disease Management: Fava beans can help break pest and disease cycles by providing a rotational break from susceptible crops. They can also attract beneficial insects, such as pollinators and natural predators of pests.
Cold Tolerance: Unlike many other cover crops, fava beans thrive in cool weather, making them ideal for early spring or late fall planting. This extends the growing season and maximizes the benefits of cover cropping.

Comparison to Other Cover Crops

Fava beans offer unique advantages compared to other commonly used cover crops such as clover, vetch, and rye.

Clover: While clover is also a nitrogen-fixing legume, it typically produces less biomass than fava beans. Clover is well-suited for intercropping and ground cover but may not provide the same level of soil improvement and weed suppression as fava beans.
Vetch: Vetch is another nitrogen-fixing legume that is often used as a cover crop. It grows well in a variety of soils and climates but tends to have a more sprawling growth habit compared to the upright growth of fava beans. Vetch can also become invasive if not managed properly.
Rye: Rye is a grass cover crop that is excellent for erosion control and weed suppression. However, it does not fix nitrogen and may require additional management to prevent it from becoming a weed itself. Rye is often used in combination with legumes like vetch or clover to balance its benefits.

Cultivation Practices for Fava Beans as Cover Crops

Growing fava beans as cover crops involves several key steps to ensure successful establishment and maximum benefits:

Site Selection and Soil Preparation: Fava beans prefer well-drained soil with a pH between 6.0 and 7.5. Prepare the soil by incorporating organic matter and ensuring good drainage. Avoid waterlogged conditions, which can lead to root rot.
Planting Time: Fava beans thrive in cool weather and can be planted in early spring or late fall. In mild climates, they can even be grown over winter. The ideal soil temperature for germination is between 50°F and 60°F.
Seeding Rate and Depth: Plant fava beans at a rate of 1-2 pounds per 1000 square feet. Sow the seeds 1-2 inches deep, spacing them 6-8 inches apart in rows 18-24 inches apart. This spacing allows adequate room for growth and reduces competition for resources.
Watering and Fertilization: While fava beans are relatively drought-tolerant, they benefit from consistent moisture, especially during germination and pod formation. Avoid overwatering, as waterlogged conditions can harm the plants. Typically, additional fertilization is not necessary due to their nitrogen-fixing ability.
Weed and Pest Management: Fava beans' dense canopy helps suppress weeds, but it is important to manage any weed growth during the early stages of establishment. Monitor for pests such as aphids and bean weevils, and implement integrated pest management strategies if necessary.
Harvesting and Termination: Fava beans can be harvested for their pods and seeds if desired. However, for cover cropping purposes, it is more common to terminate the plants before they set seeds. This is usually done by mowing, cutting, or incorporating the plants into the soil as green manure.

Economic and Environmental Impact of Fava Beans

Using fava beans as cover crops not only benefits the soil and subsequent crops but also offers economic and environmental advantages. By reducing the need for synthetic fertilizers and herbicides, fava beans help lower input costs and minimize chemical runoff into water sources. Additionally, their ability to improve soil health and structure can lead to increased crop yields and long-term sustainability.

In Summary

Fava beans are a versatile and highly beneficial cover crop that offers a range of advantages for soil health and crop production. With their nitrogen-fixing ability, robust growth, and cool-weather tolerance, they are an excellent choice for gardeners and farmers looking to improve their soil and enhance their farming practices. By incorporating popular varieties such as Windsor, Aquadulce Claudia, Banner, Superaguadulce, and Sweet Lorane into your cover cropping strategy, you can enjoy the many benefits that fava beans have to offer. Whether you're aiming to suppress weeds, reduce erosion, or boost soil fertility, fava beans are a valuable addition to any agricultural system.

Fava Beans - UC ANR Small Farms Network
This article provides an extensive overview of fava beans, highlighting their use as cover crops, livestock feed, and for vegetable production. It explains the planting schedule for fava beans in California, noting that they are typically planted from September to November for cover crops. The beans are known for their nitrogen-fixing ability, making them valuable for soil health and fertility. Additionally, the article details the plant's tolerance to frost, optimal growing conditions, and potential yields. For more detailed information, visit the article here.
Beans, Fava | College of Agricultural Sciences, Oregon State University
This article discusses the agronomic practices for growing fava beans, including proper fertilization, seeding, pest control, irrigation, and timely harvest. It emphasizes the importance of nitrogen fixation by Rhizobium bacteria, which helps supply the plant with nitrogen from the air. The article also provides specific recommendations for fertilizing fava beans, particularly in Western Oregon, based on soil tests and crop needs. For more insights, read the full article here.
Cover Crops for the Pacific Northwest – Elisabeth C. Miller Library, University of Washington
This resource offers guidance on selecting and managing cover crops in the Pacific Northwest, including fava beans. It highlights the benefits of fava beans as a cover crop, such as their ability to supply significant amounts of nitrogen to the soil, improving soil fertility and structure. The article also discusses other legumes that can be used as cover crops and their nitrogen contribution to the soil. For more details, check out the article here.