Nitrogen‐15 evaluation of fertilizer placement at planting for corn production

Abstract

Numerous studies have been reported to ascertain the benefits of starter fertilization for corn (Zea mays L.) production, but most rely on data collected by measuring early growth or grain yield at harvest. As a more conclusive evaluation, five field trials were conducted using 15 N-labeled urea-ammonium nitrate (UAN) solution (90 kg N ha −1 ) to compare single and dual subsurface band placement, as well as surface dribble and broadcasting with incorporation. Significant differences in dry matter production and total N uptake occurred between fertilized and unfertilized treatments, but not among the different placements studied. In contrast, fertilizer 15 N uptake efficiency (F 15 NUE) tended to be greater for either type of subsurface banding than for the dribble treatment, demonstrating the added sensitivity that can be achieved through isotopic measurements. More importantly, band placement consistently outperformed broadcasting, according to estimates of F 15 NUE for total aboveground biomass that ranged from 11% to 46% when UAN was banded and from 7% to 34% for broadcast applications.

Corn 15N uptake and partitioning in response to fertilizer application rate and timing

“…Since those earlier studies, there have been substantial changes in climate, advances in fertilizer N management, and corn improvement through breeding efforts, which have important impacts on N use efficiency. Renewed interest in quantifying fertilizer‐N use efficiency (F 15 NUE) or soil‐derived N (SDN) contributions in corn production has resulted in recent studies that evaluate N fertilizer sources (Griesheim, Mulvaney, Smith, & Hertzberger 2023), placement (Griesheim, Mulvaney, Smith, Nunes et al., 2023), and application timings (Griesheim et al., 2019; Spackman, 2020). The objective of the study was to quantify FDN and SDN uptake and accumulation patterns of corn across the growing season as affected by the rate and timing of fertilizer application in a corn following corn cropping system over two consecutive growing seasons.…”