Fertilizer management Effects on nitrate leaching and indirect nitrous oxide emissions in irrigated potato production

Rodney T. Venterea, Charles R. Hyatt, Carl J. Rosen

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

Potato (Solanum tuberosum L.) is a N-intensive crop, with high potential for nitrate (NO 3 -) leaching, which can contribute to both water contamination and indirect nitrous oxide (N 2O) emissions. Two approaches that have been considered for reducing N losses include conventional split application (CSA) of soluble fertilizers and single application of polymer-coated urea (PCU). The objectives of this study were to: (i) compare NO 3 - leaching using CSA and two PCUs (PCU-1 and PCU- 2), which differed in their polymer formulations, and (ii) use measured NO 3 - leaching rates and published emissions factors to estimate indirect N 2O emissions. Averaged over three growing seasons (2007-2009), NO 3 - leaching rates were not significantly different among the three fertilizer treatments. Using previously reported direct N 2O emissions data from the same experiment, total direct plus indirect growing season N 2O emissions with PCU-1 were estimated to be 30 to 40% less than with CSA. However, PCU-1 also resulted in greater residual soil N after harvest in 2007 and greater soil-water NO 3 - in the spring following the 2008 growing season. These results provide evidence that single PCU applications for irrigated potato production do not increase growing season NO 3 - leaching compared with multiple split applications of soluble fertilizers, but have the potential to increase N losses after the growing season and into the following year. Estimates of indirect N 2O emissions ranged from 0.8 to 64% of direct emissions, depending on what value was assumed for the emission factor describing off-site conversion of NO 3 - to N 2O. Thus, our results also demonstrate how more robust models are needed to account for off-site conversion of NO 3 - to N 2O, since current emission factor models have an enormous degree of uncertainty.

Original languageEnglish (US)
Pages (from-to)1103-1112
Number of pages10
JournalJournal of Environmental Quality
Volume40
Issue number4
DOIs
StatePublished - Jul 1 2011

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