Rhizobia/Legume Symbiosis

This pea root was busy fixing nitrogen into its roots all winter, preparing my soil for a growing season for other vegetables.  The light colored nodules along the roots are infections of a rhizobia bacteria.  Though the bacteria consumes carbohydrates and proteins provided by the pea, it supplies ammonia (otherwise known as a chemical fertilizer!) that the legume benefits from.  Both the pea and the bacteria benefit from this symbiosis.

I've since turned under the peas and their nitrogen-rich roots, so my carrots and beets and chard will get to benefit from the fertilized soil.