A WORLD-FIRST project will investigate the possibility of a flame-suppressing fertiliser, which could one day limit the impact of large-scale fires like Pinery and Wangary.
Project leader and SA No-Till Farmers Association research and development manager Greg Butler said the increasing practice of stubble retention prompted a literature review into how to prevent the heightened fire risk caused by the subsequent extra fuel loads.
Mr Butler said they wanted to investigate how to contain fast-moving standing stubble fires, as well as smouldering ground stubble fires.
“We found out some flame retardants are ammonium polyphosphates,” he said.
APP Phase I is a liquid fertiliser commonly used in North America and APP Phase II is used as a flame retardant in commercial products including pyjamas.
While Phase I’s chemical makeup consists of a long chain of linked phosphate, Phase II also has cross links which gives it a net-like structure and an increased flame retardant capacity.
“Diammonium phosphate has limited flame retardant capacity, APP has some more flame retardant capacity and APP Phase II has the best flame retardant capacity,” Mr Butler said.
“But their breakdown under heat and solubility is proportional as well. DAP is the most soluble, APP is less soluble and APP Phase II is less soluble again.”
The CFS will be in attendance when in-paddock trials begin at Templers in late March/early April, with different windrows burned after being subjected to different rates of fertiliser and with different application timings.
“That’ll effectively be APP Phase I and APP Phase II,” Mr Butler said.
“The treatments will be done at different rates – a low and very economical rate, a rate similar to a standard fertiliser application, and five times a standard rate.
“We’ll apply four weeks, one week, one day and one hour in advance of burning.
“The other cross-reference we’ll use is a product called a bond, which is traditionally used with fungicides so they don’t get washed off beans in rainfall.
“We’ll have APP Phase I and APP Phase II by themselves and then chemicals with a bond, and all those different rates and timings.”
Mr Butler said with no knowledge of in-paddock testing of APP Phase II, the first trial is simply gauging relative effect.
“We just want to see if it works at all or not at all,” he said. “Another thing we want to look at is how effective that fertiliser, once it starts to break down, is on the crop.”
Mr Butler said they were beginning the project with a level of caution and didn’t want to raise anyone’s hopes.
“But sometimes you have to look at stuff no one has ever done before and if we don’t look, we’ll never know,” he said. “Especially when it’s an issue as serious as fire.”
The project is being supported by the Adelaide and Mount Lofty Ranges Natural Resources Management board, through funding from the federal government’s National Landcare program.