Soil Waterlogging and Nitrogen Fertilizer Management Effects on Corn and Soybean Yields

CORE IDEAS: Excessive soil moisture resulting from extreme precipitation events during early spring can often cause decreases in corn grain yields in the midwestern United States. Each day of waterlogging resulted in an average corn grain yield loss of 0.42 Mg ha⁻¹ and 0.72 Mg ha⁻¹ in 2013 and 2014, respectively. Pre‐plant N fertilizer applications of non‐coated urea; polymer coated urea, and non‐coated urea+nitrification inhibitor resulted in 19% higher yields compared to the non‐treated control in 2014. Effects of rescue N fertilizer were seen on soybean yields in the succeeding year after corn, while rescue N affected corn yields only in 2014. Climatic conditions including rainfall and air temperature had a significant role in crop response to waterlogging and N fertilizer treatments. In the midwestern United States, excessive soil moisture resulting from extreme precipitation events during early spring can often cause decreases in corn (Zea mays L.) grain yields and escalate N loss. A field trial was conducted from 2013 to 2015 in Northeast Missouri to determine the effects of soil waterlogging duration, pre‐plant N and rescue N fertilizer applications on corn and succeeding soybean [Glycine max (L.) Merr] production. Plots were either non‐flooded or flooded for durations of 1, 3, or 7 d when corn was at V6 growth stage. Pre‐plant N fertilizer treatments included non‐treated control (CO), urea (NCU), urea plus nitrapyrin (NCU+NI), and polymer coated urea (PCU) applied at 168 kg N ha⁻¹. A rescue N fertilizer application of 0 or 84 kg N ha⁻¹ of urea plus N‐(n‐butyl) thiophosphoric triamide (NBPT) (NCU+UI) was applied at V10 growth stage. Each day of waterlogging resulted in an average corn grain yield loss of 0.42 and 0.72 Mg ha⁻¹ in 2013 and 2014, respectively. Pre‐plant N fertilizer applications of NCU, PCU, and NCU+NI resulted in 19% higher yields compared to CO in 2014. Effects of rescue N fertilizer were seen on soybean yields in the succeeding year after corn, while rescue N positively affected corn yields only in 2014. These results indicated that rescue N fertilizer applications are not effective if drought conditions occur after its application in corn. Climatic conditions including rainfall and air temperature had a significant role in crop response to waterlogging and N fertilizer treatments.