Assistant Professor University of Idaho Aberdeen, Idaho
Irrigation is a limiting factor in improving potato yields and quality, and mitigating external and internal defects, especially in the high desert growing regions of the Pacific Northwest. Furthermore, improper irrigation can result in large variations in tuber size profile, maturity, and postharvest storability. Beginning in 2024, three commercial varieties and one clonal selection (Teton Russet, Russet Burbank, Clearwater Russet, and A12305-2adg) were grown at the University of Idaho’s Aberdeen R&E Center under differing irrigation rates that were selected as a percentage of average evapotranspiration (50%ET, 75%ET, 100%ET, and 125%ET). Soil moisture was monitored using 8 soil moisture sensors per treatment (METER Group, 2024) and applied irrigation and natural precipitation was measured using rain gauges located at several points within the treatments. Irritation was applied using a custom sprinkler irrigation design that applied 0.5 inches of water per hour. One year of data showed that varying irrigation rates impacted each variety differently. Russet Burbank, Clearwater Russet and Teton Russet had the highest total yields when irrigated at 100% ET, however A12305-2adg produced greatest total yields at 75% ET. Irrigation rate also affected external defects with 125% ET resulting in a greater number of tubers with knobs and growthcracks compared to 100% ET. Marketable yields for Teton Russet was reduced when irrigated at 125% ET due to a 76% increase in tubers with growth cracks and 175% increase in knobs. Water use efficiency (WUE), defined as the yield of tubers produced by total water applied, was highly significant among varieties and based on irrigation rates. Following one year of data, the lowest irrigation rate, 50%ET, had the highest WUE.
