POLYMER COATED UREA IN POTATO PRODUCTION

Nitrogen (N) is the most important mineral nutrient in potato (Solanum tuberosum) production. Studies show a steady, but not excessive, supply of N is important for maximum tuber yield, size, and solids, as well as minimal internal and external defects. Although more costly and labor intensive dry broadcast applications, growers typically apply the majority of N through the irrigation water in-season in order to maximize yield components. A controlled release N fertilizer, in the form of polymer-coated urea (PCU), is a possible alternative to the grower’s standard practices. A newly formulated PCU may meet plant demand more timely and efficiently through temperaturecontrolled release of N into the soil solution. This improved efficiency could increase yield and tuber quality, prevent excess N loss from leaching and denitrification, and allow a more convenient and less labor-intensive fertilization system. The objectives of this study are to determine the effects of PCU on the yield and quality of Russet Burbank potatoes grown in Southeast Idaho. Nitrogen was applied at four rates (33, 67, 100, or 133% of recommended) with four methods of application, namely: 1) urea at emergence, 2) PCU at emergence, 3) split urea with half applied at emergence and the remaining applied in three in-season applications, and 4) PCU at pre-plant. The PCU pre-plant treatment was only applied at the 67% rate. Results showed increases in US No. 1, marketable, and total yield, as well as increases in crop value for PCU treatments (especially the 67% rate) over the other treatments.