Modelling plausible impacts of Biological Nitrification Inhibition in Australian farming systems

Retaining nitrogen (N) in soils in the form of ammonia (NH4) by inhibiting nitrification processes has been long hypothesised as a solution to N loss from denitrification and leaching of nitrate (NO3) below the root zone. Enhanced-efficiency fertilisers (EEF) that inhibit nitrification offer a partial solution, but they are ineffective on soil and residue derived NO3. More recently, research has shown nitrification reactions are inhibited by root exudates from some crops (e.g., wheat, rice, sorghum, maize, canola) and these biological nitrification inhibitors (BNIs) may contribute to maximising N uptake, improving nitrogen use efficiency (NUE) and minimising environmental nitrogen pollution. However, there have been variable results between BNI production, BNI exudation and nitrification efficacy, likely dependent on genotype and environmental conditions. This investment will utilise a modelling systems approach using the current body of literature on BNI to assess the prospects of potential impacts from BNI for the wheat, canola and sorghum crops in Australian farming systems.