OSU research saves water and cuts pollution for onion farmers

Onions being sliced
OSU researchers are helping farmers grow better onions with less water and fertilizer. (Photo by Stephen Ward)

Southeastern Oregon provides a dry and sunny climate for growing onions. But farmers there face a dual challenge: making the most of the region’s limited water stores, and minimizing overfertilization of the soil, which can lead to groundwater contamination.

Onions are mostly water--86 percent water, to be precise. That water has to come from somewhere. Former practices called for overhead irrigation combined with heavy use of nitrogen fertilizer, which wasted water and led to yield-crushing e. coli and other disease-causing organisms.

Clint Shock and his team of scientists at the Malheur Experiment Station near Ontario have spent the last three decades developing and refining new tools, notably in-soil sensors and per-plant drip irrigation systems, that have dramatically cut water and fertilizer inputs while boosting onion yield and quality.

Shock noted that in the 1980s, onion producers put on 400-500 pounds of nitrogen per acre, yet only 125 pounds were taken up by the plants. The rest ran off into streams or seeped into groundwater. The Ontario area became Oregon’s first Groundwater Management Area in 1991, and the Experiment Station’s subsequent discoveries have resulted in a reversal of that trend. Now the plants receive 150 to 180 pounds per acre, and drip irrigation has decreased water usage from 4-5 acre-feet of water to 2.5-3 acre-feet. (An acre-foot represents a hypothetical foot of water over an acre of land—about 326,000 gallons.)

For Oregon’s onion farmers, who contributed $125 million to Oregon’s agriculture production in 2015, these improvements mean less money spent on water and fertilizer inputs and more profit in the marketplace.

Source: Clint Shock, professor, OSU Crop and Soil Science

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