Roots of the Mammoth Soy Bean
This picture shows the nodules due to the nitrifying bacilli, through which the leguminous plants are enabled to perform a feat that other plants find impossible,-namely the direct extraction of nitrogen from the air. Other plants might starve for want of nitrogen, although bathed in the atmospheric ocean which is so largely composed of nitrogen. But the legumes, thanks to the particular types of bacilli that colonize the roots, can get a supply, or a partial supply, of nitrogen, without waiting for it to be combined and made into soluble compounds. Nowadays cultures of the nitrifying bacilli are sometimes thrown on a fleld, as one sows grain or the innoculated seed, put out under the trade name "Nitragin", is sown.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 7 Chapter 3