Hybrid brown coal-urea fertiliser reduces nitrogen loss compared to urea alone

Biplob K. Saha, Michael T. Rose, Vanessa Wong, Timothy R. Cavagnaro, Antonio F. Patti

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13 Citations (Scopus)


Synthetic nitrogen (N) fertilisers, such as urea, are susceptible to rapid dissipation from soil. More gradual release of mineral N from fertiliser may reduce the off-site movement of mineral N, thereby enhancing N supply to crops and minimising negative off-site impacts. We hypothesised that granulation of urea with humified brown coal (BC) delays mineral N release and maintains higher concentrations of N in soil than conventional urea granules. Four different brown coal-urea granules, with C:N ratios of 1‐10, were prepared by pan granulation. Advanced spectroscopic and X-ray powder diffraction (XRD) techniques confirmed loading of urea-N into the BC structure. Nitrogen-release from BCU granules was slower than from urea, resulting in higher N retention over a longer period for increasing growth and N uptake by crop plants. This trend increased with higher loading of BC, emphasising the significant role of BC in N retention. These findings support the hypothesis that BC is suitable for developing slow release N fertilisers.

Original languageEnglish
Pages (from-to)1496-1504
Number of pages9
JournalScience of the Total Environment
Publication statusPublished - 1 Dec 2017


  • Brown coal
  • Fertiliser N use efficiency
  • Pan granulation
  • Slow release fertiliser
  • Urea

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