Spring wheat yield and grain quality response to nitrogen rate

• Published in: Agronomy journal Vol. 114; no. 4; pp. 2562 - 2572
• Main Authors: Walsh, Olga S, Marshall, Juliet, Nambi, Eva, Shafian, Sanaz, Jayawardena, Dileepa, Jackson, Chad, Lamichhane, Ritika, Ansah Owusu, Emmanuella, McClintick‐Chess, Jordan
• Format: Journal Article
• Language: English
• Published: 01-07-2022
• ISSN: 0002-1962; 1435-0645
• DOI: 10.1002/agj2.21101

Nitrogen (N) is the most limiting nutrient in cereal production, yet its use efficiency remains very low at only 35%. Nutrient use efficiency (NUE) is crucial for increasing crop yield and quality while reducing fertilizer inputs and minimizing environmental damage. Optimum N rates that maximize yield without reducing NUE have been found to vary from location to location. This field study assessed the effect of N rates on the yield and quality of spring wheat (Triticum aestivum L.) at five locations in southern Idaho in 2015–2017. Nitrogen was applied as urea (46–0–0) immediately after planting at five rates: 0, 84, 168, 252, and 336 kg ha–1. Nitrogen application improved grain quality (increased protein) even when no increase in yield was noted. Nitrogen use efficiency and N uptake were affected by N rate at only 2 and 4 of 14 site‐years, respectively. These observations highlight the challenging task of pinpointing the appropriate N rates for optimizing wheat yield, grain protein, N uptake and NUE; and the importance of adjusting N rates based on location, year, and prevalent environmental conditions.
Core Ideas
Application of all N fertilizer at planting is not efficient for wheat.
Nitrogen fertilizer rates for wheat should account for site‐ and year‐specific conditions.
When prescribing N rates to wheat, yield potential and responsiveness to N should be considered.
Higher N rates resulted in enhanced grain protein content, but low N use efficiency.