The virtues of alfalfa in drought

Alfalfa, which recently handed over its”Demon Crop” title to almonds, is really a far better crop in drought than common wisdom suggests, according to U.C. Davis’s Dan Putnam:

Contrary to popular belief, alfalfa has several unique positive biological properties and advantages when it comes to water. Due to these properties, alfalfa is remarkably resilient when it comes to severe drought conditions.

Among other things, Putnam argues that “deficit irrigation” – the ability to cut way back on water during the heat of a summer drought – provides important water management flexibility. The full piece is worth reading.

One Comment

  1. Somewhere in that article, the fact that alfalfa production uses — 5 or 6 acre-ft per year — got lost, along with the fact that almonds use less water both per acre and total, along with fact that 80% of Colorado River alfalfa and 80% of Central Valley almonds get exported to Asia, meaning all that water use has no benefit whatsoever to America’s food supply much less ‘food security’.

    Just saying. Not making a parallel to massive food exports from Ireland that continued full bore during the height of the Irish Potato Famine under the then-new doctrine of laissez-faire free markets, though that wikipedia article instructive.

    As far as I know, not one drop of Colorado River or CAP water is used to grow almonds because they need too many winter chill days (36-42 degrees) which they certainly aren’t going to see in ag land west of the Tucson-Phoenix line. This is significant because with water deliveries shut off from northern California, we have two uncoupled systems so sparing almond water does not help LA’s MWD.

    Almonds, like pecans, can be grown at cooler elevations south of Tucson and along the NM border. In fact Arizona has 29 farms with 326 acres of almonds. Meanwhile California has 6,841 almond operations occupying 935,804 acres. That’s a 3000:1 ratio. Note a CAP pipeline extension to the Rosemont mine and thus to pecan groves in the Santa Cruz valley could change these numbers.

    The article at hand offers the oft-made valid point that, unlike with trees, alfalfa water can be reduced during the summer without killing it. UC Davis estimates an annual savings of one acre-ft per year could be realized without fallowing, thus with relatively little money needed to compensate the grower. So ‘deficit alfalfa’ becomes a minimally disruptive strategy to free up water.

    Those savings may not be realizable for massive acreages of Colorado River-irrigated alfalfa in the Imperial Valley (ditto Coachella and Palo Verde irrigation districts) because it is so hot there in summer. The mean historic temperature for Brawley on May 17th is already 94 degrees, with the record for that 109. July has hit 120º.

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