Abstract

Combining a foliar fertilizer and fungicide in a single application could complement soil-applied nitrogen (N) and reduce application costs. Limited research has evaluated such combinations for high-yield corn (Zea mays L.) production systems. This research evaluated the effect of mixing order of enhanced-efficiency foliar N (30-0-0-0, Nitamin) rates (0, 9, and 28 L ha^-1) with pyraclostrobin under different crop-yield environments (soil applied N at 84, 169, and 337 kg ha^-1) on crop injury, disease severity, chlorophyll content, grain quality, and yield at Novelty and Albany, Missouri, in 2010 and 2011. There was no effect of 30-0-0-0 at 9 or 28 L ha^-1 on corn yields in low- (soil applied N at 84 kg ha^-1) or medium-yield environments (soil applied N at 169 kg ha^-1). In a high-yield environment (soil applied N at 337 kg ha^-1 at Novelty and Albany), 30-0-0-0 at 9 L ha^-1 increased grain yields 0.38 Mg ha^-1 (3.7%) compared to the non-treated control, but 30-0-0-0 at 28 L ha^-1 did not increase yield due to 3-4% crop injury. In a high-yield environment (> 9.4 Mg ha^-1), pyraclostrobin increased yields 3.9 to 7.1% (0.38 to 0.7 Mg ha^-1) compared to the non-treated plants. This study found no significant effect of mixing order on corn yield response when 30-0-0-0 was applied with pyraclostrobin at 0.055 kg ai ha^-1. The severity of diseases (Cercospora zea-maydis, Puccinia sorghi, and Exserohilum turcicum), which was less than 12% depending on the treatment, was affected by soil-applied N rate, 30-0-0-0 rate, and pyraclostrobin, depending on the site-year. Pyraclostrobin at 0.11 kg ai ha^-1 (7.1%) and 30-0-0-0 at 9 L ha^-1 (3.7%) were the highest-yielding treatments compared to the non-treated control with good crop safety.

This work is licensed under a Creative Commons Attribution 4.0 License.