Technical Abstract: The alkali bee, Nomia melanderi, is native to deserts and semi-arid desert basins of the western United States. It is a very effective and manageable pollinator for the production of seed in alfalfa (=lucerne) and some other crops, such as onion. It is the world¿s only intensively managed ground-nesting bee. Alfalfa seed growers now construct large subirrigated silty nest sites for this bee, supplying them with salt-crusted surfaces. Minimal subsequent maintenance makes this the most cost-effective pollinator of alfalfa. Densities of 400 nests/m2 over a hectare or more can be obtained with this gregarious bee. The largest managed nesting aggregations contain 1.5 million nests. Nest sites can remain populous for more than 50 years with vigilant moisture and pest control. In her lifetime, each female¿s foraging activities in alfalfa results in an estimated 1/3 pound of seed being produced.