With some rainfall (and snow in the mountains) in November and December, the water availability picture may brighten somewhat, but as Dr. Ken Shackel, UC Davis, said at an Almond Conference workshop on Irrigation Strategies for Drought Management, “No one has to be told we’re having a drought — it’s serious.”
Dr. Shackel had some general advice for growers with limited water availability:
- Almond growers anticipating reduced levels of available water should spread out that reduction over the season, typically mid-March to mid-November, as much as possible in proportion to
almond evapotranspiration (ETc).
- Control weeds!
- There is no benefit from heavy pruning, using so-called antistress or anti-transpiration products, or whitewash.
- Mild to moderate water stress at hullsplit, which may happen
unintentionally if trees are on a deficit irrigation program, means
less hull rot and speeds up hullsplit.
- Be aware that different soils within an orchard may result in different levels of stress among the trees.
Be careful, and use a pressure chamber to determine which
trees may become too stressed. Bruce Lampinen, also with UC Davis, made the point that tree density has increased, along with yields, since the last drought. “Drought will have a bigger impact this year because yields are higher, there is more canopy, and that needs more water,” he said. “The best growers are getting 4,000 pounds per acre in orchards with 80% light interception, which takes 56 inches of water,” he added, whereas a yield of 2,560 pounds per acre takes only 36 inches of water.
Farm advisors Blake Sanden, Kern County; Allan Fulton, Tehama County; and David Doll, Merced County, underscored the critical importance of system tune-up and maintenance to optimize distribution uniformity. This is done through such actions as adjusting pressure regulators and keeping emitters free from plugging, which can boost irrigation system efficiency and save water. Sanden talks further about system maintenance in this video.
The entire presentation, shared at The Almond Conference, can be viewed here.