Advantages Of Fixing Nitrogen With Cover Crop

A cover crop is a plant used to cover the soil rather than for the purpose of being harvested. It is mostly used to improve soil health, provide nutrients for other plants, slow erosion, smother weeds, attract beneficial insects and help control pests and diseases.

Try planting a cover crop of legumes. After flowering and before the seeds set, you can simply till under the plants. As these plants decay, they will raise the nitrogen in the soil without the need for commercial fertilizers. They will make nitrogen available to your lawn or plants that cannot get nitrogen from the air.

Best Cover Crop For Nitrogen Fixation

1. Alfalfa (Medicago sativa) 
This is one of the most powerful nitrogen fixers of all legumes and may fix 250–500 lb of nitrogen per acre. Alfalfa is also strong in iron and is also a good source of phosphorus, potassium, magnesium, and trace minerals.
 

2. Clover (Trifolium): 
Red Clover and White Clover can fix up to 150 lb of nitrogen per acre. They are used in spring or fall.
 

3. Peas or beans
They can be used as a summer nitrogen-fixing cover crop or harvested for food. Both ways, they enrich the soil with nitrogen.
Among them are Fava Beans, Green Beans or French Beans, Runner Beans, Soybeans, Chickpeas, Cowpeas or Black-Eyed Peas, Garden Peas, Field Peas, Lentils, Pigeon Peas, and Everlasting Sweet Pea.

While they all fix nitrogen, some are better at it than others. Fava beans top the list of nitrogen fixers, deriving 90% of their nitrogen from fixation. Peas and Lentils follow close behind at 80%, Chickpeas at 70%, and Soybean and dry beans at 50%

4. Vetches (Vicia): 
Hairy Vetch, American Vetch, Wood Vetch, and Tufted Vetch. Vetches are winter-hardy and suitable for cooler seasons. Hairy vetch is the strongest type that is a good nitrogen-fixing winter cover crop. It is planted in early fall for the roots to establish before the first frosts.
 

5. lupins (Lupinus)

Lupins or bluebonnets are both an agricultural crop and an ornamental garden plant. They fix nitrogen, which benefits the soil, and act as green manure. As an added bonus, they add color and eye-catching beauty to any flower bed or garden spot. Native lupins also support wildlife by attracting native bees, bumblebees, and other pollinators.

6. Peanuts (Arachis hypogaea)
Peanuts are a legume with amazing nitrogen-fixing properties and are an excellent crop to plant in rotation with other crops.