Polymer Coated Urea (ESN): Increase In Nitrogen Use Efficiency and Potato Tuber Size and Quality.

Potato (Solanum tuberosum L.) production is sensitive to a steady, adequate supply of nitrogen (N). Synergistically optimizing grower profits while maximizing N use efficiency (NUE) is critical to conserve nonrenewable natural resources used to manufacture N fertilizer and minimize N pollution to water and the atmosphere. Polymer coated urea (PCU, Environmentally Smart N or ESN^®) is one type of N fertilizer which uses temperature-controlled diffusion to control N release to better match plant demand and mitigate environmental losses. Twelve studies were performed on Russet Burbank potato with urea, split-applied urea, and polymer coated urea (PCU) fertilizer at rates of 0, 33, 67, and 100% of the expected optimum N rate. Urea and PCU were applied at time of plant emergence with soil incorporation via hilling. The split applied urea was applied 50% at hilling and the remaining applied at 8-11 day intervals after the onset of tuber bulking phase. Averaged across rates, the polymer coated urea resulted in significantly higher US No. 1 yield than hilling and split applied urea an average of 8.5 and 5.2 Mg ha^-1, respectively. Total yield was not significantly impacted in all fields. Tuber size increased an average of 38 g per tuber. Use of properly manufactured polymer coated urea, such as ESN, is a best management practice for potato production.