Identification of a new N‐heterocyclic core structure with nitrification inhibition activity in Australian soils

Nitrification inhibitors (NIs) can be utilised to reduce nitrogen losses and environmental implications of synthetic fertilisation. However, current commercial NIs provide variable results under Australian field conditions, with effectiveness influenced strongly by soil characteristics and environmental factors. A library of nitrogen-containing heterocycles was synthesised and subsequently assessed as NIs, in five soils from eastern Australia under laboratory conditions. Several of the potential NIs performed statistically better than the control treatments, prolonging the residence time of ammonium-N. When compared to treatment with commercial inhibitor DMPP, some of the potential NIs showed promising results at elevated temperatures and low soil pH.

involved in the soil microbial process of nitrification, the multi-step oxidation of ammonium (NH4 +) to nitrate (NO3 – ). Using nitrification inhibitors (NIs) is one approach to increase nitrogen use efficiency (NUE) of synthetic fertilisers, by extending the residence time of applied N in the less-vulnerable NH4 + form (Subbarao et al., 2006). Many chemicals with NI activity have been identified, with Ncontaining heterocycles among the most potent. With current commercial NIs like 3,4-dimethylpyrazole phosphate (DMPP) failing to provide consistent results particularly at varying soil pH or temperature (Mahmood et al., 2017), a need exists to identify new inhibitors that offer more consistent and predictable performance.