Plants that contribute to the nitrogen fixation include the family vegetables – Fabaceae – with taxa such as clover, soybeans, alfalfa, lupins, peanuts, and rooibos. They contain symbiotic bacteria called Rhizobia within nodules in their root systems, producing nitrogen compounds that help the plant grow and compete with other plants. When the plant dies, the fixed nitrogen is released, making it available to other plants and this helps fertilize the soil. The vast majority of legumes have this association, but few genera (e.g., Styphnolobium) do not. In many traditional and organic farming practices, fields are rotated through different types of crops, which usually include one or more of the clover or buckwheat (family Polygonaceae), often referred to as „green manure“.
The nitrogen fixation crops we grow on our farm are beans and winter peas. We produce them on the local market. Beans as healthy protein food for humans, and peas for animal feed.