Brian Edwards-Tiekert, I think you need to look again at California's Alfalfa industry, perhaps bigger than you may have estimated this morning.

Alfalfa is now the biggest field crop in California, with more than 1 million acres planted. The booming dairy industry has raised the level of importance of the forage from basically a rotational forage crop to a more important cash crop.
http://westernfarmpress.com/alfalfa-yield-monitor-providing-solid-data-c...

HISTORY OF ALFALFA IN CALIFORNIA

Although the first recorded attempt to cultivate alfalfa as a crop in the US was in Georgia in 1736, this and other subsequent eastern colonial efforts were largely unsuccessful (Oakley and Westover, 1922; Barnes et al., 1988). Contrary to the pathway of many crops which were important in the East and then moved west, alfalfa gained its first important foothold in the US in California and other western states of the expanding nation in the 19th Century.

Alfalfa had been introduced to Spain by the Moorish invasions of the Eighth Century, and was closely tied with the horse culture of the Iberian peninsula, and thereby military power. Due to this linkage, alfalfa likely accompanied the Spanish colonial expeditions to South America and Mexico in the 16th Century, and is thought to have been introduced into present-day Southwestern US by early Spanish expeditions. However, there is no record of these introductions, and the important introductions of alfalfa into California and the United States came during the Gold Rush around 1850 (Barnes et al., 1988).

California agriculture prior to the 1850s consisted of sleepy rancheros with the predominant economic products being cattle hides and tallow for shipment to eastern ports, Mexico, and South America. Boston, with its shoe industry, was a major recipient. Some Missions had by this time a long history of irrigation of row crops and vines on a small scale, but these were later replaced by the Mexican and American rancheros. Previously, the Native American people of California had represented about 1/3 of the Indian population of the continental US before Spanish contact. However, these peoples were largely non-agricultural, unlike their brethren from the East and Southwest. There is no reference to alfalfa being grown in California much before the 1850s.
https://umdrive.memphis.edu/g-sig/www/alfalfa.htm