Unlike Carbon Dioxide, plants are unable to absorb the Nitrogen that is present in air, and instead they must access it via the ground. Nitrogen fixers are a fascinating bunch. In partnership with bacteria (Rhizobia) which are hosted in nodules on their roots, nitrogen fixing plants are able to take atmospheric Nitrogen and convert it into a form accessible by the plant. As the roots die back, leaves drop, or when the plant is tilled into the ground, the plant's nitrogen is released into the surrounding soil, paving the way for other species.Nitrogen fixers are a natural (and historical) alternative to synthetic fertilisers which should be avoided. They are often misused and can lead to marine eutrophication and groundwater contamination amongst other eco-maladies.Some plants included in this skilful array of floral chemists are:
Each of these plants also make for excellent winter cover crops; readying the ground for your spring veggie planting!Since the seeds of legumes (peas, beans and other pulses) are the best source of protein in the entire plant kingdom, the joys of growing them are twofold. Just dig them into the ground once you've harvested your crop and look forward to healthy, nitrogen-rich soil.Image: Oksana2010/Shutterstock