My Account: Log In | Join | Renew
Search
Author
Title
Vol.
Issue
Year
1st Page

Abstract

 

This article in SSSAJ

  1. Vol. 43 No. 4, p. 726-728
     
    Received: Oct 24, 1978
    Published: July, 1979


 View
 Download
 Alerts
 Permissions
 Share

doi:10.2136/sssaj1979.03615995004300040020x

Studies of Nitrous Oxide Emission from a Grass Sward1

  1. O. T. Denmead,
  2. J. R. Freney and
  3. J. R. Simpson2

Abstract

Abstract

The exchange of nitrous oxide (N2O) between soils and the atmosphere is believed to play an important part in controlling stratospheric ozone levels, but so far, very little information is available on rates of emission or absorption of N2O by soils in the field. The paper reports measurements of N2O exchange made over 5 months from winter to summer in an unfertilized, mown, grass sward.

Ambient air was drawn continuously in an open flow system through the above-ground portion of a steel cylinder driven into the ground. The enrichment or depletion of N2O in the air stream was measured with an infrared gas analyzer. Exchange rates as small as 1 ng N m−2 sec−1 could be measured.

Nitrous oxide was always emitted from the sward, even at very low soil moisture contents. The emission showed a clear diurnal cycle in phase with the temperature of the surface soil; peak emission rates occurred in the afternoon, minima near sunrise. Additions of water as small as 5 mm increased emission rates markedly. Both results suggest that most of the N2O was produced close to the soil surface rather than at depth in the soil profile. Further, the production of N2O was accompanied by a net increase in soil nitrate.

Emissions were largest in the spring. With the soil moist to less than field capacity, average daily emissions over periods of several days ranged from 0.6 to 2.5 mg N m−2.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © . Soil Science Society of America