Jumbo. Colossal. Super colossal. The superlatives used to rate Treasure Valley onions suggest they could take over the world. And in a way, they have. Many of the onions sold in U.S. grocery stores during fall and winter come from this valley at the border of Oregon and Idaho.
After 30 years of research, scientists at OSU’s Malheur Agricultural Experiment Station have helped Treasure Valley onion producers triple their acreage in onions and reduce water use, pesticides, fertilizer, and runoff. And, in the process, the onions got bigger. Clint Shock, the station superintendent, and colleagues replaced old furrow systems with drip irrigation that applied moisture and fertilizer slowly to the root zone and kept topsoil in place and groundwater protected. They developed sensors to initiate irrigation only when soil moisture dropped below a particular level.
As a result, onions grew large and well-centered, perfect for making onion rings. And, Shock said, residues of nitrate and the herbicide DCPA are decreasing in the valley, despite the three-fold increase in onion production.