Fertilizer 15N uptake efficiency in Midwestern corn production

The use of synthetic fertilizer nitrogen (N) can lead to significant increases in corn (Zea mays L.) yields, but incomplete uptake of fertilizer N reduces profitability and can result in serious environmental damage. Many strategies have been proposed for increasing fertilizer N uptake efficiency (FNUE), and most evaluations rely on grain yield differences between fertilized and unfertilized plots. As a much more direct approach, field trials were conducted using 15N as a tracer to evaluate surface and subsurface sidedressing, dual- and single-banded starter applications, as well as KNO3, urea-ammonium nitrate (UAN), and liquid urea additions made in-season. These evaluations were each conducted in two growing seasons on conventional production fields of contrasting fertility under second-yr corn or a corn-soybean rotation. Over the 17 site-years studied, isotopic estimates of FNUE (F15NUE) for total aboveground biomass ranged from 7 to 54% and the percentage of N derived from the fertilizer (NDFF) never exceeded the percentage of N derived from the soil (NDFS), highlighting the importance of soil N supply for Midwestern crop production. When compared to applications made at planting, the amount of 15N taken up in-season was much higher during the 2017 and 2020 growing seasons, and while the subsurface application outperformed the surface application made at V9, both offered the same fundamental advantage in that fertilizer N was supplied during the period of maximal crop uptake. Starter band placement was more beneficial than broadcasting, according to isotopic estimates of F15NUE for total aboveground biomass that ranged from 15 to 46% when UAN was banded and from 7 to 46% for broadcast applications. When applied in-season, the three 15N sources often differed significantly in NDFF and F15NUE, both of which decreased in the order: KNO3 > UAN > urea. Although not always apparent from grain yields alone, altering N application, placement, and timing can increase FNUE for Midwestern corn production.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Natural Res & Env Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Griesheim, Kelsey

Contributors dc:contributor

• Mulvaney, Richard L
• Arai, Yuji
• Below, Fred E
• Yu, Zhongjie
• Smith, Tim J

• Fertilizer N Uptake Efficiency
• 15n
• Corn
• Soil Fertility

Statement dc:rights

• Copyright 2022 Kelsey Griesheim

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/117737

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F117737