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Fig. 2. Long-term average county-wide dryland wheat grain yields for Adams County, Washington, and Sherman County, Oregon, superimposed with crop-year precipitation from Lind, WA, and Moro, OR. Data show that grain yield in both counties has increased by an average of 28 kg ha–1 yr–1 since reliable county-wide grain yield data became available in the late 1920s. Long-term average precipitation is 242 mm at Lind and 288 at Moro. The average value of wheat produced in the dryland region in Fig. 1 exceeds $300 million annually. Yield data are from USDA-NASS (2007) and Oregon State University (Sandy Macnab, personal communication, 2006). Precipitation data are from the WSU Dryland Research Station at Lind and the OSU Sherman Station at Moro.
