Nitrogen fertilizer and pronitridine rates for corn production in the Midwest U.S.

Abstract

ContextReducing nitrogen (N) losses can be accomplished by applying recommended N rates and using nitrification inhibitors (NI). In some agricultural systems, managing N application rate or using a NI could improve N use efficiency and increase crop yields. ObjectiveThe objectives of this 13 site-year study were to determine the agronomic optimum N rate (AONR) application rate using linear plateau and quadratic plateau models, determine the optimum pronitridine rate when applied with 70 % of the recommended N amount, and evaluate the effect of nitrapyrin and pronitridine on corn (Zea mays L.) yield. MethodsIn this experiment, pronitridine and nitrapyrin were used as NIs and were applied in the fall and spring. This research was conducted in the US in Illinois (IL), Missouri (MO), and Nebraska (NE) from 2016 to 2019. ResultsThe AONR varied from 176 to 291 kg ha-1 in different site-years. The optimal pronitridine rate was predicted using the generalized additive model (GAM) for each site. A pronitridine rate of 5.6 g kg-1 N and 8.2 g kg-1 N was recommended for well drained (NE) and poorly drained (MO and IL) sites, respectively. The pronitridine application at an average rate of 5.6 g kg-1 N increased corn grain yield 4 % compared to the non-treated control. Economic analysis showed an increase in gross margin returns of 32–67 $ ha-1 in poorly drained soils (MO & IL) when applied at 8 g kg-1 with fall and spring N application. Whereas 10–30 $ ha-1 higher gross margins were observed in well-drained soils (NE) with an application of 4 g kg-1 of pronitridine for fall and spring application timings. ConclusionThe differences in AONR and pronitridine rate prediction observed in this study emphasize the variability caused by factors such as the soil, environment, and their interaction with the N cycle. When we evaluated pronitridine and nitrapyrin with all site years combined, no differences between the two NIs were observed in terms of corn yield production. SignificanceOur findings are the first to quantify corn yield response for pronitridine applications at different locations and multiple rates in the Midwest U.S. The results of this study highlight the optimum pronitridine optimum rate for improved corn yield in poorly drained and well-drained soils in the Midwest U.S. Profitability of pronitridine can be improved by applying an optimum rate based on N requirements and soil conditions.