Field-level comparison of nitrogen rates and application methods on maize yield, grain quality and nitrogen use efficiency in a humid environment

Appropriate nitrogen (N) management practices are of critical importance in improving N use efficiency (NUE), maize (Zea mays) yield and environmental quality. A six-year (2005–2010) on-farm trial was conducted in Ottawa, Canada to assess the effects of N rates and application methods on grain yield and NUE. In four out of the six-year study, grain yield increased by 60–77 kg ha−1 by sidedress, compared to 49–66 kg ha−1 for each kg N ha−1 applied at preplant. Grain yield response to N between the two strategies was similar in the other growing seasons. Sidedress strategy required 15 kg N ha−1 less of the maximum economic rate of N (MERN) than preplant application. Our results indicate that sidedress application of 90–120 kg N ha−1 with a starter of 30 kg N ha−1 resulted in greater yield, grain quality and NUE than preplant N application in this cool, humid and short growing-season region.