Keelnatham T. Shanmugam, University of California
Raymond C. Valentine, University of California
California Agriculture 30(11):4-7. DOI: 10.3733/ca.v030n11p4.
Not available – first paragraph follows:
Our major food plants may be divided into two types-those which need nitrogen fertilizer (cereal grains, such as corn, wheat, and rice) and those which do not (alfalfa, soybeans, and other legumes). The latter group produces protain by manufacturing its own nitrogen in a process that uses energy from the sun-hence, the term “solar protain.”