California Growers Look for Long-term Solutions to Conserve Resources

By Dirk Lenie

While recent storms have ended the drought in many parts of the state, California growers are planning for the future — looking for long-term solutions to combat future water shortages.

Years ago, when there was an abundance of water and inexpensive labor, gravity flow systems worked well in California. Because water resources are now scarce and labor costs are rising, it’s imperative that growers consider newer forms of irrigation in order to wisely maximize limited resources and remain sustainable.

Among the options, replacing flood irriga- tion with “pressurized irrigation” (e.g., drip, center pivot or permanent set sprinklers) could help address water shortages as well as the state’s rising labor costs.

According to the USDA’s 2013 Farm and Ranch Irrigation Survey, of the 7.5 million acres of land currently irrigated in California, the vast majority (4.5 million acres) still use flood (gravity flow systems) for irrigation, with 2.3 million acres using gravity systems exclusively, which are much less efficient than other methods.1

Commonly used on row crops and vegetables, center pivots have sprinkler heads that can be lowered to just inches above the tops of plants, minimizing water loss from evaporation and wind drift. Switching from flood to center pivot irrigation is both water- and labor-efficient and typically results in the following:

28 Irrigation TODAY | April 2017

• Up to 75 percent labor savings • Up to 45 percent less water use • Energy savings of more than 33 percent • Fewer pumping hours, which extends pump life

• More even application for up to 50 percent higher yields

• Less runoff for fertilizer and chemical savings2

Using microirrigation, or a drip system, is generally more efficient than using a flood system because it slowly delivers low volumes of water directly to the plants’ roots, eliminating runoff and evaporation. Drip irrigation systems typically consist of pressurized tubing that runs along crop rows. The tubing is fitted with emission devices at specific distances that allow water to drip into the root zones. While initial investment costs per acre may be higher than other systems, there are many benefits to microirrigation. Results from a study published in the World Academy of Science, Engineering and Technology indicate the following:3

• The drip irrigation method saved 55.4 percent water and gave 22 percent more yield as compared to that of the furrow irrigation method.

• Higher water-use efficiency of about 4.87 kilograms per cubic meters was obtained in the drip irrigation method, whereas lower water-use efficiency of about 1.66 kilograms per cubic meters was obtained in furrow irrigation.

Photos courtesy of Lindsay Corporation

For California grower Ed Hale Jr., converting from flood to drip irrigation resulted in reduced costs and improved yields.

According to an article in the Sacramento Bee about Hale, “He converted a 2,600- acre alfalfa field to drip irrigation. Flood irrigation would have caused lots of water wasted, he said, because the field sloped too much, causing water to run off too fast. He estimates drip uses about two-thirds less water, yet the crop yield has doubled.”4

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