Result for: Crops: Corn for grain
4R Practices: Metadata Project

Relationships of Nitrous Oxide Emissions to Fertilizer Nitrogen Recovery Efficiencies in Rain-fed and Irrigated Corn Production Systems: Data Review

Dr. Tony Vyn

Lead Researcher:

Dr. Tony Vyn

Department of Agronomy, Henry A. Wallace Chair in Crop Sciences

Purdue University

Start Date: 2014

End Date: 2015

Collaborating scientists and universities

  • Dr. Rex Omonode, Purdue University
  • Dr. Ardell Halvorson, USDA-ARS

Project Summary

Nitrous oxide (N2O) emissions from corn production systems are a large societal concern because so much of the N fertilizer applied to crop production in the United States is applied to corn, and because agriculture alone accounts for the majority of N2O emissions from all sources. The IPCC (2006) has estimated that an average of approximately 1.0% of the N fertilizer applied is lost as N2O, but we know from our own studies in rain-fed corn production that estimated emissions can sometimes exceed the equivalent of 5% of the N in the N fertilizers applied.

Over the years of scientific monitoring of N2O emissions, the predominant reporting method has been to quantify episodic and/or cumulative growing season N2O emissions per unit land area. Later refereed publications included acknowledgement of the importance of reporting yield scaled N2O emissions, but not until relatively recently has there been a plea to focus on emissions within the context of actual N use efficiencies. The recent meta-analysis by Decock (2014) highlighted the low proportion of past N2O emission studies that included critical information on treatment effects on crop N export (let alone any mention of crop N uptake).

The central hypothesis of this proposal is that increased corn plant N uptake (as a fraction of the fertilizer N applied) will be associated with reduced N2O emissions on area-scaled, yield-scaled, and NRE-scaled (i.e. plant N uptake per unit of N fertilizer initially applied) methods of interpreting relative N2O emissions from different management systems for corn production.

Project Goals:

  • Relate cumulative growing-season nitrous oxide (N2O) emissions to existing data on corn whole-plant N uptake (NU) and apparent nitrogen recovery efficiencies (NRE) in previous N2O emissions research in North America involving changing N management treatments (whether focused on N source, N rate, N timing and/or N placement) in both irrigated and rainfed corn production systems.

  • To illustrate the relationships between corn N uptake (apparent N recovery) and N2O emissions in different production environments and at different corn yield levels.

Project Results:

  • A data review found relationships between nitrogen efficiency terms and nitrous oxide emissions would be more discernable if published studies measured total nitrogen uptake in aboveground biomass and reported nitrogen recovery efficiency data.

  • The timing of nitrogen application affected the relationship between nitrogen recovery efficiency and nitrous oxide emissions, with a stronger relationship in treatments with side-dressed nitrogen applied at corn growth stages V6-8 and V14.

  • Nitrogen uptake is a better indicator of nitrous oxide emissions for systems applying nitrogen pre-plant.

Annual Reports