Examples of crops that replenish nitrogen in the soil
1. Legumes: Beans, peas, lentils, alfalfa, clover, and other leguminous plants have a symbiotic relationship with nitrogen-fixing bacteria that live in nodules on their roots. These bacteria take nitrogen from the air and convert it into a form that plants can use, thereby enriching the soil with nitrogen.
2. Brassicas: Crops such as broccoli, cabbage, cauliflower, kale, and mustard are considered biofumigants because they release compounds that suppress soil-borne pests and diseases. They also have a deep root system that brings up nutrients from lower soil layers, including nitrogen.
3. Grasses: Certain grass species such as ryegrass, fescue, and bermudagrass have the ability to accumulate nitrogen in their leafy biomass, which can be returned to the soil when the grass is mowed or grazed by animals.
4. Cover crops: Cover crops are grown to protect the soil from erosion, improve soil structure, and increase organic matter. Some popular cover crop species that replenish nitrogen include hairy vetch, crimson clover, field peas, and winter rye.
5. Soybeans: Soybeans have the same nitrogen-fixing capability as other legumes, but they also have a high protein content, which makes them a valuable crop for animal feed and human consumption. They are often grown as a rotation crop with corn to improve soil fertility and reduce the need for synthetic fertilizers.
Crops that replenish nitrogen in the soil are known as nitrogen-fixing crops. Here are a few examples:
1. Legumes: Leguminous plants such as peas, beans, soybeans, lentils, and clover have a mutualistic relationship with nitrogen-fixing bacteria. These bacteria form nodules on the plants' roots, converting atmospheric nitrogen into a usable form for the plants.
2. Alfalfa: Alfalfa is a perennial legume that not only fixes nitrogen but also has deep roots that can draw nutrients from deep within the soil, making it an excellent soil conditioner.
3. Fava beans: Fava beans are another legume crop that fixes nitrogen and is commonly grown as a cover crop during the winter.
4. Chickpeas: Chickpeas, also known as garbanzo beans, are nitrogen-fixing legumes that are not only valuable for their edible seeds but also as a cover crop.
5. Peanuts: Peanuts are another legume crop that fixes nitrogen and is commonly grown in warm climates.
6. Red clover: Red clover is a popular cover crop that fixes nitrogen and improves soil fertility.
7. Winter vetch: Winter vetch is a cover crop that grows during the colder months and fixes substantial amounts of nitrogen.
These crops help replenish nitrogen in the soil and can be used in crop rotation systems to improve soil fertility naturally.