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ARS Home » Plains Area » Lincoln, Nebraska » Agroecosystem Management Research » Research » Publications at this Location » Publication #421544
Research Project: Integrated Agricultural Systems for a Resilient Circular Bioeconomy in the Central Plains

Location: Agroecosystem Management Research

Title: Impact of fertilizer strategy on nitrogen (15N) transformation through crop, microbial, and mineral pools

Author
item REKHI, MANJOT - University Of New Hampshire
item DALY, AMANDA - University Of New Hampshire
item GARDENER, BRIAN - Ag Spectrum Company
item Schmer, Marty
item Jin, Virginia
item FREY, SERITA - University Of New Hampshire
item GRANDY, STUART - University Of New Hampshire

Submitted to: Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 11/11/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Over 50% of the crop nitrogen (N) originates from the soil organic matter pool (SOM-N) while the contribution of applied N fertilizers to this pool remains unknown. To investigate this, we conducted a micro-plot experiment with corn in New Hampshire (NH) and Nebraska (Neb) to show how the type, rate, and placement of starter fertilizers affect internal N cycling using the isotope tracing technique. At planting, InFurrow (“InF”), a proprietary biostimulant multi-nutrient solution (AgSpectrum, USA) was injected in crop row, while urea ammonium nitrate (28-0-0; “UAN”) solution was banded 4-6 inches from crop row. These fertilizers were applied alone and in combination (“Both”) at single and double application rates to yield total rates of 5 (InF-1X), 10 (InF-2X), 74 (UAN-1X), 79 (Both-1X), 148 (UAN-2X), and 158 (Both-2X) kg N/ha labeled at 10 at% with 15N. Soil core and plant samples were collected at V3 and V6 stages and separated into several N pools for analysis: whole soil, mineral-associated OM (MAOM), total dissolved N (TDN), and microbial biomass N (MBN), roots, and shoots. Fertilizer-N was found to be rapidly stored (within 20 days of planting) in MAOM. Small applications of InF fertilizer had similar or greater recovery in shoots and MAOM than high rates of UAN. Regardless of treatment, >50% of corn shoot N was derived from SOM. Doubling application rates resulted in lower fertilizer NUE. In conclusion, this study highlights the importance of microbial processing and mineral ‘storage’ of fertilizer-N to optimize the NUE of starter fertilizer in agricultural soils.