The effect of soil moisture at application on the behaviour of four nitrogen fertilisers in the presence of 3,4-dimethylpyrazole phosphate

Brooke Kaveney1, Jason Condon1, Greg Doran1

1 Graham Centre for Agricultural Innovation, Wagga Wagga, NSW, 2650, www.grahamcentre.net, bkaveney@csu.edu.au

Abstract:

A laboratory soil incubation experiment was conducted using the nitrification inhibitor 3,4-dimethylpyrazole phosphate in conjunction with four different agriculturally relevant nitrogenous fertilisers to examine the effects of soil moisture at application on inhibitor behaviour. Soil moisture influenced the mineral N concentrations of the nitrogen fertilisers.  Fertilisers that were applied to moistened soils recorded significantly higher mineral N concentrations than when they were applied to dry soils. Of the four fertilisers applied to a moistened soil, urea had the lowest NH4+ and NO3 concentrations after a week of incubation. However, in dry soils both urea and UAN recorded significantly lower mineral N concentrations. Losses were attributed to volatilisation which occurs as urea is converted to NH4+. Regardless of the soil moisture conditions, DMPP effectively suppressed nitrification for all fertilisers. Fertilisers without DMPP recorded higher NO3 concentrations as the NH4+ was oxidised as part of the nitrification process. Experimental results demonstrate that different soil moisture conditions can influence the behaviour of nitrogen fertilisers but not DMPP.

Host

The Australian Society of Agronomy is the professional body for agronomists in Australia. It has approximately 500 active members drawn from government, universities, research organisations and the private sector.

Photo Credits

David Marland Photography david_marland@hotmail.com Graham Centre for Agricultural Innovation, Charles Sturt University

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