A frequently asked question here in New Mexico: Does it make sense to spend our precious water growing alfalfa?

That's a specific case of a broader question frequently being asked here in the West regarding the tradeoffs between urban and agricultural water use. It's closely related to the price of water, because irrigated ag depends on low-cost water, and cities are frequenly willing to pay far more for an acre foot than a farmer can afford.

The question gets interesting play in a piece by Melinda Burns about exporting hay from California to Japan:

Container ships from Japan unload electronics and other goods in the Port of Long Beach, and the farmers fill up the containers with hay for the trip back across the Pacific. Since the containers would otherwise return empty, it ends up costing less to ship hay from Long Beach to Japan than to California's Central Valley.

"Everything is done for economics," said Ronnie Leimgruber, an Imperial Valley hay grower who is expanding into the export market. "Japan cannot get hay cheaper. The freight is cheaper from Long Beach than from anywhere else in the world."

Water is cheap for valley farmers, too: urban rates there are four times as high. It costs only $100 to irrigate an acre of hay in the desert for a year.

I don't know of anyone exporting hay from New Mexico to Japan, but the underlying question comes up here all the time. What do you think? Water managers believe there is an inevitable transition underway from ag to urban use, as cities buy up water writes because they water is more "valuable", in dollar terms, coming out your tap than it is irrigating alfalfa fields. Do you agree?