Ben Rigby

Theme 2 and 4

Improving the environmental and agronomic potential of nitrification inhibitors by further understanding their dynamic interactions with soil

Nitrification inhibitors (NI’s) slow nitrification (the conversion of ammonia to nitrate) and can be a useful means to reduce the environmentally damaging nitrogen loss associated with fertilisation. However, even the most successful commercially available NI’s have variable efficacy in different soils. This variation is usually linked to the key soil properties of clay, organic carbon content and pH. Whilst being useful general indicators, it is difficult to reliably predict the efficacy of NI’s using these soil properties alone. Because clay and organic carbon content are intrinsically related to other soil properties, it is hypothesised soil properties influenced by clay, organic carbon and pH will allow better prediction of NI bioactivity and therefore efficacy. Consideration of the chemical nature of the individual NI being investigated is critical, as the available NI’s are distinct compounds. This research aims to further understand how different NI’s interact with soil, and how this influences nitrification inhibition.

Ben’s honours research investigated the influence of crop species on fertiliser nitrogen uptake, and whether the rhizosphere microbial community influenced crop fertiliser recovery. His main area of interest is plant nutrition, in particular, the provision of nutrients from soil through nutrient cycling processes. Ben began his PhD at The University of Melbourne in 2020 following undergraduate study at La Trobe University. Whilst at La Trobe University he worked for a number of years with the Crop Agronomy Group, assisting with research related to increasing fertiliser nitrogen use efficiency and improving crop yields through optimising flowering time.