Urea ammonium nitrate placement methods, row patterns, and irrigation effects on corn productivity in a humid subtropical region

Authors: VARGAS, AMILCAR - Mississippi State University; SINGH, GURBIR - University Of Missouri; KAUR, GURPREET - University Of Missouri; LO, TSZ HIM - Mississippi State University; SPENCER, G.D. - Mississippi State University; KRUTZ, JASON - Mississippi State University; GHOLSON, DREW - Mississippi State University

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2023
Publication Date: 1/8/2024
Citation: Vargas, A., Singh, G., Kaur, G., Lo, T., Spencer, G., Krutz, J.L., Gholson, D.M. 2024. Urea ammonium nitrate placement methods, row patterns, and irrigation effects on corn productivity in a humid subtropical region. Agrosystems, Geosciences & Environment. https://doi.org/10.1002/agg2.20462.
DOI: https://doi.org/10.1002/agg2.20462

Interpretive Summary: The loss of nitrogen (N) in humid subtropical regions has an adverse affect on crop yields. This study was conducted to determine whether N dynamics could be manipulated through either planting geometry or fertilizer placement. The effects of irrigation (irrigated and rainfed), row pattern (single- and twin-row), and N placement (surface dribble, one knife, two knives, and control) on corn productivity and N use efficiency were investigated at Leland, Mississippi, on a Bosket very fine sandy loam. The total N rate was split into two equal halves at V2 and V6 growth stages. The effects of row pattern and N placement were consistent between both the irrigated and rainfed environments. There was no interaction between row pattern and N placement nor did row pattern affect corn productivity or N use efficiency parameters. Rainfall patterns did impact the results. In 2020, when less than 30 mm of rainfall occurred from the first N application through 2 weeks after the last N application, corn grain yield and agronomic N efficiency were not different among placement methods and averaged 11.1 Mg ha-1 and 20.3 kg grain kg-1 fertilizer N, respectively. However, in 2021, applying N with one knife increased corn grain yield by 7% to 14% compared to the two knives and surface dribble application methods; in that year, 235 mm of rainfall occurred from the first N application through 2 weeks after the last N application. Applying N with one knife appears to consistently improve crop productivity and N use efficiency parameters for both irrigated and rainfed environments.

Technical Abstract: Crop yields are adversely affected by nitrogen (N) losses in humid subtropical regions. This study was conducted to determine whether N dynamics could be manipulated through planting geometry and fertilizer placement. The effects of irrigation (irrigated and rainfed), row pattern (single- and twin-row), and N placement (surface dribble, one knife, two knives, and control) on corn (Zea mays L.) productivity and N use efficiency were investigated at Leland, Mississippi, on a Bosket very fine sandy loam. The total N rate was split into two equal halves of 128 kg N ha-1 at V2 and V6 growth stages. The effects of row pattern and N placement were consistent between irrigated and rainfed environments. There was no interaction between row pattern and N placement nor did row pattern affect corn productivity or N use efficiency parameters. In 2020, when less than 30 mm of rainfall occurred from the first N application through 2 weeks after the last N application, corn grain yield and agronomic N efficiency were not different among placement methods and averaged 11.1 Mg ha-1 and 20.3 kg grain kg-1 fertilizer N, respectively. However, in 2021, applying N with one knife increased corn grain yield by 7% to 14% compared to the two knives and surface dribble application methods; in that year, 235 mm of rainfall occurred from the first N application through 2 weeks after the last N application. Applying N with one knife appears to consistently improve crop productivity and N use efficiency parameters for both irrigated and rainfed environments.