LAUSR

Decisions in irrigation management can greatly impact the overall sustainability of potato production. A field study was conducted in 2018 and 2019 to evaluate the impacts of different irrigation regimes on yield and quality of three russet potato varieties. For Russet Burbank, fry quality at harvest and at 4 and 8 months after harvest was assessed. During early growth stages, the standard practice of irrigating to maintain 60–80% soil moisture was employed. The irrigation treatments were applied during the late tuber bulking and maturation growth stages, and consisted of irrigation at 125%, 100%, 75%, and 50% of daily evapotranspiration (ET). We found that 125%ET provided no increase in total yield and marketable yield compared to other treatments in 2018, and it produced similar marketable yield to 100%ET in 2019. Total yield, but not marketable yield, of 125%ET and 100%ET was significantly higher than the number under 50%ET in 2019. In both years, increasing irrigation rate led to a decrease in irrigation efficiency and water-use efficiency. Irrigation rate had no significant effects on tuber quality at harvest and during storage. This study indicated that over-irrigation at 125%ET was not beneficial to profitable potato production in the Upper Midwest of the US, and deficit irrigation at 75%ET during late tuber bulking and tuber maturation could potentially result in more sustainable water use while not jeopardizing tuber growth. The results support the possibility of adopting late-season deficit irrigation for growing potatoes in the region, though more years of research would allow for a better understanding of the impacts of this practice.