Biplob K Saha1, Michael T Rose2, Vanessa Wong3, Timothy R Cavagnaro4, Antonio F Patti5. 1. School of Chemistry, Monash University, Clayton, Victoria 3800, Australia; Department of Agricultural Chemistry, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh. 2. NSW Department of Primary Industries, Wollongbar Primary Industries Institute, Wollongbar, NSW 2477, Australia. 3. School of Earth, Atmosphere & Environment, Monash University, Clayton, Victoria 3800, Australia. 4. The Waite Research Institute and The School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, PMBI, Glen Osmonds, South Australia 5064, Australia. 5. School of Chemistry, Monash University, Clayton, Victoria 3800, Australia. Electronic address: tony.patti@monash.edu.
Abstract
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.
Synthetic nitrogen (n class="Chemical">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.