Nitrogen fertilizer management for nitrous oxide (N2O) mitigation in intensive corn (Maize) production: an emissions reduction protocol for US Midwest agriculture

TLDR

Nitrous oxide is a major greenhouse gas from intensive agriculture, and in the US Midwest fertilizer nitrogen rate is the best single predictor of its emissions, serving as a transparent, tangible, and manageable proxy despite other influencing factors. The study proposes a transparent, scientifically robust protocol for agricultural offset projects to generate fungible GHG emission reduction credits in the emerging US carbon cap and trade market. The protocol couples predicted N₂O flux with the maximum return to N approach to set economically profitable nitrogen rates that incentivize reductions without yield loss, while also addressing baseline, additionality, permanence, variability, and leakage to provide economic and environmental incentives for adoption. If widely adopted, the protocol could cut N₂O emissions from fertilized row‑crop agriculture by over 50%.

Abstract

Nitrous oxide (N2O) is a major greenhouse gas (GHG) product of intensive agriculture. Fertilizer nitrogen (N) rate is the best single predictor of N2O emissions in row-crop agriculture in the US Midwest. We use this relationship to propose a transparent, scientifically robust protocol that can be utilized by developers of agricultural offset projects for generating fungible GHG emission reduction credits for the emerging US carbon cap and trade market. By coupling predicted N2O flux with the recently developed maximum return to N (MRTN) approach for determining economically profitable N input rates for optimized crop yield, we provide the basis for incentivizing N2O reductions without affecting yields. The protocol, if widely adopted, could reduce N2O from fertilized row-crop agriculture by more than 50%. Although other management and environmental factors can influence N2O emissions, fertilizer N rate can be viewed as a single unambiguous proxy—a transparent, tangible, and readily manageable commodity. Our protocol addresses baseline establishment, additionality, permanence, variability, and leakage, and provides for producers and other stakeholders the economic and environmental incentives necessary for adoption of agricultural N2O reduction offset projects.