Fertilizer and irrigation management effects on nitrous oxide emissions and nitrate leaching

Bijesh Maharjan, Rodney T. Venterea, Carl Rosen

Research output: Contribution to journalArticlepeer-review

47 Scopus citations

Abstract

Irrigation and N fertilizer management are important factors affecting crop yield, N fertilizer recovery efficiency, and N losses as nitrous oxide (N2O) and nitrate (NO3-). Split application of conventional urea (split-U) and/or one-time application of products designed to perform as enhanced-efficiency N fertilizers may mitigate N losses. The objective of this study was to compare the effects of controlled-release polymer-coated urea (PCU), stabilized urea with urease and nitrification inhibitors (IU) and split-U on direct soil-to-atmosphere N2O emissions, NO3- leaching, and yield for fully irrigated and minimum-irrigated corn in loamy sand. Indirect N2O emissions due to NO3- leaching were estimated using published emission factors (EF5). Split-U increased yield and N uptake compared with preplant-applied PCU or IU and decreased NO3- leaching compared with PCU. Direct N2O emissions were significantly less with IU or split-U than with PCU, and there was a trend for greater emissions with split-U than with IU (P = 0.08). Irrigation significantly increased NO3-leaching during the growing season but had no significant effect on direct N2O emissions. After accounting for significantly increased yields with irrigation, however, N losses expressed on a yield basis did not differ and in some cases decreased with irrigation. Post-harvest soil N and soil-water NO3- in spring showed the potential for greater N leaching in minimum-irrigated than fully irrigated plots. Indirect emissions due to NO3- leaching were estimated to be 79 to 117% of direct emissions using the default value of EF5, thus signifying the potential importance of indirect emissions in evaluating management effects on N2O emissions.

Original languageEnglish (US)
Pages (from-to)703-714
Number of pages12
JournalAgronomy Journal
Volume106
Issue number2
DOIs
StatePublished - 2014

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