GRAIN producers do have scope to cut crop fertiliser inputs, but have to make sure they choose the right paddocks to do so, according to researchers.
And soil health considerations from changed management practices also have to be taken into account, as it could change the dynamic of nutrient mineralisation and soil biological health.
Nigel Wilhelm, a crop nutrition expert at the South Australian Research and Development Institute (SARDI) said there was an opportunity to reduce phosphorus rates in the right paddocks, but warned against 'silver bullet' alternatives to standard phosphorus fertilisers as a cost-cutting measure.
"A near tripling in the price of most phosphorus fertilisers over the last couple of years has unfortunately promoted a lot of interest in 'silver bullet' solutions to managing phosphorus nutrition through the use of products other than standard phosphorus fertilisers," Dr Wilhelm said.
"Things that did not work when standard fertilisers were cheap are still not going to work now that standard fertilisers are more expensive."
Meanwhile, CSIRO Entomology’s Dr Vadakattu Gupta warned growers of the implications for soil biological health of reducing inputs, especially in terms of carbon, required to break down to provide beneficial soil microbes with a source of energy.
"Soil biological health is essential for the long-term sustainability of Australian agriculture," Dr Gupta said.
"Healthy soils are needed as soil organisms regulate a number of biological processes integral to nutrient recycling, carbon turnover and build-up, clean water and air, plant health, soil structural stability and sustained productivity.
"Processes such as decomposition, nutrient mineralisation and disease suppression are a product of the activities of soil organisms.
"Most soil microbes require carbon as a source of energy, and crop management practices such as crop rotation, stubble retention, tillage and fertiliser inputs influence carbon inputs."
