Controlled release nitrogen fertilizer use in potato production systems of eastern Canada

Noura Ziadi1, Mervin St.Luce1, Athyna N. Cambouris1, and Bernie J. Zebarth2

1Agriculture and Agri-Food Canada, 2560 Hochelaga Blvd, Quebec, QC, Canada, G1V 2J3, [email protected]

2Agriculture and Agri-Food Canada, PO Box 20280, 850 Lincoln Rd., Fredericton, NB, Canada E3B 4Z7

Abstract

Nitrogen (N) is the most limiting essential nutrient for potato (Solanum tuberosum L.) and its management is important from both economic and environmental standpoints. Controlled-release N fertilizers, such as polymer-coated urea (PCU), could reduce N losses and increase N use efficiency (NUE) by matching the release of N with potato N uptake. During the last 10 years, different studies were conducted in eastern Canada (Quebec and New-Brunswick) to evaluate the effectiveness of PCU in potato production. A total of nine site-years were conducted between 2006 and 2012 to compare the PCU to the most used conventional N sources. Their effects were assessed on various parameters including yield, specific gravity, NUE, chlorophyll meter readings nitrate (NO3) leaching, and nitrous oxide (N2O) emissions along with soil nitrate availability during growing seasons and at harvest. Our results showed that PCU can maintain or increase marketable tuber yield and quality, increase NUE, and reduce NO3 leaching, particularly in excessively wet years. However, higher N availability from PCU may have implications for N2O emissions and non-growing season N losses. Evidence of the overall economic advantages of using the PCU in potato production, if any, will be needed to influence a more widespread adoption of PCU by producers.