Improving potato irrigation efficiency with mobile drip irrigation, newer cultivars, and changes in cultural management practices.

As water shortages and irrigation restrictions become more prevalent, the need for new more efficient irrigation technologies and techniques are essential for keeping potato growers globally competitive and profitable. Three 2024 field trials near Othello, WA investigated potential solutions to these problems including utilizing new irrigation technology (Mobile Drip Irrigation (MDI)), adopting water efficient cultivars, and adjusting plant population and spatial arrangement. Trial one compared MDI with conventional overhead irrigation using three season-long evapotranspiration (ET) replacement rates: 60%, 80%, and 100%. Trial two compared crop water productivity of four new, unreleased clones to Clearwater Russet and Ranger Russet using the three MDI irrigation treatments. Trial three compared 6 plant spatial arrangement treatments (32 and 34 in. row widths x four in-row seed piece spacings (6, 9, 12, and 15 in.)) and four season-long ET replacement irrigation rates: 60%, 80%, 100%, and 120%. Use of MDI allowed for a 20% or greater irrigation rate reduction to achieve comparable yields and economic returns as the 100% ET conventional irrigation treatment. The potato clone OR12133-1 (Vantage Russet) had higher crop water productivity, producing higher yields and economic returns than all trialed clones and cultivars. Changes in spatial arrangement (plant population) failed to improve water crop productivity; however, yield and economic return were both positively correlated with irrigation rate and plant population. The highest yield (994 CWT) was achieved with the highest plant population (32,670 plants/A) irrigated with the most water (120% ET). Inversely, the lowest plant population (12,299 plants/A) irrigated with the least amount of water (60% ET) produced the lowest yield and economic return. Spatial arrangement alterations may not allow for reduced irrigation rates, however, newer cultivars and irrigation methods, such as MDI, may help improve crop water productivity and/or reduce water potato irrigation rate, thereby saving water for other life uses.