A slow release nitrogen fertiliser produced by simultaneous granulation and superheated steam drying of urea with brown coal

Michael T Rose, Emily L Perkins, Biplob K. Saha, Evone C.W. Tang, Timothy R. Cavagnaro, W. Roy Jackson, Karen P. Hapgood, Andrew F.A. Hoadley, Antonio F. Patti

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Background: The inefficient use of nitrogen (N) fertiliser as a consequence of N losses from soil is a pressing issue in broad-acre agricultural systems. The research reported here tested the hypothesis that granulation of synthetic N fertiliser (urea) with a natural organic C resource (brown coal) would reduce fertiliser N loss from the soil system. 

Results: Urea-enriched brown coal granules were simultaneously formed and dried within a pilot-scale superheated steam dryer. After application to unplanted soil columns, the urea-brown coal granules reduced nitrous oxide emission by up to 40 %, reduced mineral nitrogen leaching and maintained higher levels of N in topsoil when compared to conventional urea alone. Reduced gaseous N losses without a reduction in plant N uptake were also observed in planted soil columns treated with urea-brown coal granules. 

Conclusions: Brown coal-urea blended fertiliser showed potential for more efficient use of N in the long term and has environmental benefits in retaining more N in the soil.

Original languageEnglish
Article number10
Pages (from-to)1-14
Number of pages14
JournalChemical and Biological Technologies in Agriculture
Issue number1
Publication statusPublished - 2016


  • Controlled-release fertiliser
  • Greenhouse gas emissions
  • Lignite
  • Nitrous oxide
  • Soil enhancement
  • Superheated steam drying

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