Drought strategies for the long haul

You would have to be living in a cave to not know California is in the third year of a severe natural and regulatory drought.

The media heralds the fact daily, but the sobering reality of California’s water crisis — not just a drought — hit home when longtime consulting plant pathologist Tom Yamashita of Turlock, Calif., told a group of agronomists that there will be no new water developed in the state in their lifetime.

This means a water harvesting and delivery system designed for 20 million people decades ago will not increase significantly as the state’s population continues expanding from the current 37 million, roughly 8 percent of the U.S. population.

Agriculture relies heavily on that surface water collection and distribution system, and the No. 1 industry in the state faces the most serious challenge in dealing with the state’s water crisis.

Yamashita, who owns Sunburst Plant Disease Clinic in Turlock, spent a half day offering suggestions to Crop Production Services (formerly Western Farm Service) agronomists on how to help producers survive with less water.

It was no one-year plan, Yamashita says, explaining that with annual rainfall or better, it will take at least five years from today to recover and replenish water supplies as a result of the past three years of drought.

Yamashita says the drought is the worst he has seen in his 30 years of work in California agriculture.

He calls it a “huge, huge problem” as evidenced by some of his drought survival recommendations like using chainsaws to cut away at least 25 percent to as much as 50 percent of an orchard’s canopy to reduce water use.

That is very draconian, but it may be the only way growers with little or no water available this year can save an orchard in hopes of having more water after this season.

His other recommendations to survive this drought year are less dramatic. They include:

• Line irrigation water flumes or trenches with plastic.

• Adjust flood irrigation heads to reflect soils. High heads and/or shorter runs for sandy soil; moderate heads and/or moderate runs for loam soils and slower head and/or longer runs for clay soils.

• Do not flood irrigate the entire width of orchard middles. Rather irrigate down a single furrow along one side — not both sides — of a tree row berm.

• Avoid row/field crop sprinkler irrigation (solid set, portable and/or hose connect) when winds are greater than 10 miles per hour.

• Keep weed growth short in orchards by frequent mowing. Mowed vegetative growth serves as a buffer against unusually high soil temperatures and it acts to curb wind and water erosion.

• Utilize solid set, portable hand-move and hose line sprinkler irrigation only on solid plantings (alfalfa, sod, sorghum, grass seed, etc.)

• Level ground to maximize irrigation sprinkler efficiency.

• If naturally hilly terrain, use smaller nozzles and keep soil activated with microbial enhancement.

For drip or mini-sprinklers:

• Use of fine meshed sand filtration for drip systems.

Mini-Sprinklers can get by with coarser sand filters.

• Train the roots to come towards the nutrients or to the “sweet spot.” Roots will grow into a zone of the soil if they sense nutrients are present in that zone.

• Maintain a moderate to high degree of microbial activity to maximize the plant’s ability to harvest nutrients from that soil.

• Apply nutrients incrementally versus slugging fertilizers early in the season.

• Deliver the fertility package in well-designed fertilizer programs.

• Recognize that many agronomic problems are the result of uneven and imbalanced nutrient deliveries to the plant.

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