Assessing Management of Nitrapyrin with Urea Ammonium Nitrate Fertilizer on Corn Yield and Soil Nitrogen in a Poorly-Drained Claypan Soil

H. Habibullah,Kelly A. Nelson,Peter P. Motavalli

doi:10.5539/jas.v9n11p17

Abstract

Use of nitrification inhibitors (NI) in agricultural production systems is considered a risk management strategy for both agricultural and environmental considerations. It can be utilized when risk of reduced nitrogen (N) fertilizer use efficiency or yield, and risk of pollution from mineral N is high which can occur in poorly-drained soils that are vulnerable to waterlogging and runoff. Field research was conducted on corn (Zea mays L.) from 2012 to 2015 in Missouri, USA on a poorly-drained claypan soil. Treatments consisted of two application timings of urea ammonium nitrate (UAN) fertilizer solution [pre-emergence (PRE) and V3 growth stage], two application rates (143 and 168 kg N ha-1) in the presence or absence of nitrapyrin, and a non-treated control. UAN at 143 kg ha-1 with nitrapyrin at the V3 growth stage resulted in the highest yield (8.6 Mg ha-1). Similarly, pre-emergence application of UAN 168 kg ha-1 with nitrapyrin resulted in greater yields (7.7 Mg ha-1). UAN application rates and timings affected soil NO3-N and NH4-N concentrations more than the presence or absence of nitrapyrin during the growing season. A side-dress application of a lower rate of UAN with nitrapyrin at V3 was effective in poorly-drained soils when risk of N losses during the growing season due to unfavorable precipitation events and other environmental variables was high. A pre-emergence application of UAN with nitrapyrin was also effective and it may eliminate the need for split-application of N fertilizer later in the season thereby reducing the workload on growers during the growing season.

Highlights

Careful selection of N fertilizer sources, application rates, and application timings are common strategies to better match the crops N demand with supply
An application of urea ammonium nitrate solution (UAN) at 143 kg ha-1 with nitrapyrin at V3 had the highest grain yield (8.6 Mg ha-1), followed by 7.7 Mg ha-1 yield with UAN at 168 kg ha-1 with nitrapyrin applied PRE
Soil NO3-N and NH4-N concentrations were generally affected by UAN application rates and timings, and relatively less by the application of nitrapyrin

Summary

Introduction

Careful selection of N fertilizer sources, application rates, and application timings are common strategies to better match the crops N demand with supply. Application of N fertilizer in the spring at the time of planting or soon after emergence of the crop is a common fertilization practice for corn production in the Midwestern U.S (Randall & Sawyer, 2008). There is lack of research studies which have investigated the effects of a new formulation of nitrapyrin (Instinct II, Dow Agro Sciences, Indianapolis, IN) and UAN fertilizer solution on soil N, corn N status, and grain yield. Few studies have reported significant increases in grain yields. One exception was Maharjan et al (2017) who observed grain yield increases with application of UAN and nitrapyrin only in one out of two years when rainfall was relatively lower. The NI might not have had significant effects on yields in those studies since they were conducted with irrigated systems and NI typically works best in soils that experience saturated conditions

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