Fertilizer research

, Volume 13, Issue 3, pp 199–207 | Cite as

The influence of sward mass, defoliation and watering on ammonia volatilization losses from an Italian ryegrass sward topdressed with urea

  • E. H. Hoult
  • J. W. McGarity


Using intact pasture sods with 0.15m2 surface area and sealed in volatilization chambers, the influence of the mass of herbage on the ammonia volatilization losses following a surface application of urea was determined. Ammonia volatilization loss increased as sward mass decreased. This effect was still evident in poorly established pastures.

Under drying conditions the timing of defoliation and water applications relative to the application of urea was also shown to influence ammonia volatilization patterns and magnitude of loss. Delaying defoliation promotes a reduction in ammonia volatilization losses while delayed watering resulted in increased losses.

Key words

ammonia volatilization urea pasture defoliation water application 


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Copyright information

© Martinus Nijhoff Publishers 1987

Authors and Affiliations

  • E. H. Hoult
    • 1
  • J. W. McGarity
    • 1
  1. 1.Division of Soil Science, Department of Agronomy and Soil ScienceUniversity of New EnglandArmidaleAustralia

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