Like other legumes its root nodules contain bacteria, Sinorhizobium meliloti, with the ability to fix nitrogen, producing a high-protein feed regardless of available nitrogen in the soil. Its nitrogen-fixing abilities (which increases soil nitrogen) and its use as an animal feed greatly improved agricultural efficiency. (The nitrogen comes from the air, which is 78 percent molecular nitrogen.)

2008 WI Alfalfa Yield and Persistence (WAYP) Program Summary

Alfalfa Management
This is the CCA pre test MS PowerPoint training module covering  general principles of alfalfa management.  Developed by Dan Undersander, UW Extension Forage Agronomist

Redesigning Alfalfa for Dairy Cattle
A MS PowerPoint presentation by Neal Martin et al., USDA Dairy Forage Research Center