Nitrogen is a vital nutrient for plant growth and although about 78% of the earth’s atmosphere is nitrogen, most plants cannot utilize this. The majority of nitrogen is provided in the form of industrially produced fertilizers. Nitrogen fixing plants, on the other hand, are hugely beneficial in any ecosystem because they have the ability to transform nitrogen from the air into the soil. When their leaves fall and their roots die, the excess nitrogen is released back into the soil where it is picked up by other plants in the area and utilized for their own growth. The plants are also capable of growing in poor soils and improving them through their nitrogen fixation.
In this way various trees and plants growing next to each other (including the nitrogen fixers playing their unique role), can thrive in harmony. This benefits the plants themselves, but also the soil, microbes, insects and animals, and last but not least- us humans. PERMACULTURE is a fairly new term applied to this really old concept.