High‐frequency Trickle Irrigation and Row Spacing Effects on Yield and Quality of Potatoes1

Abstract

AbstractSoil water is a major limiting factor in the production and quality of potatoes (Solanum tuberosum L.). The objectives of this research were to determine the effects of trickle irrigation under controlled soil matric potential and two row spacings on the yield, quality, and nutrient contents of potatoes. Potatoes, trickle irrigated with nutrient solution and grown on 100‐cm row spacing (CSI) on sandy loam (Typic Palendult) soil, yielded 76% more marketable potatoes than those trickle irrigated under a plastic mulch and grown on twin row spacing (TRI) and 206% more than 100‐cm spaced, nonirrigated potatoes (CSNI). Water deficit, calculated by subtracting rainfall from 80% of pan evaporation, was 14.0 cm. Soil matric potentials 15 cm from the soil surface were not different for the CSI and TRI treatments irrigated, respectively, with amounts of water equivalent to 60 and 43% of the water deficit. The N and Mg contents of tubers were increased by irrigation. Leaf petiole nitrate N of CSI and TRI potatoes was consistently greater than 16,000 ppm, a critical level for Russett Burbank potato production in Idaho, but fell significantly below that level for the CSNI potatoes after an extended drought.