A new use for chicken manure

Kate Raston
Wheatbelt NRM's Tracey Hobbs with Living Farm's Richard Devlin in the trial crop.

Poultry farmers have spent years trying to find a market for their chicken manure, and a solution may now be in sight with help from the forestry and broadacre cropping industries.

A trial near York is using a combination of leftover thinnings or prunings from pine plantations, mixed with chicken manure, to spread on wheat crops.

The product contains high levels of organic nitrogen, and useful levels of phosphorous and potassium and has already recorded a healthy visual response, although October rain has delayed harvest with the initial yield data not expected for another month.

The three-year trial is being funded by natural resource management group Wheatbelt NRM, and co-ordinated by York consultants Living Farm.

Adding another element to the project is the involvement of WA Biofuels, which has found a use for the forestry thinnings that would otherwise be left on the plantation floor to decompose.

The manager of biofuels and forestry Darryl Outhwaite said his company had developed a process to turn these thinnings into bedding material for chicken farms.

"Traditionally poultry operations relied on sawdust from mills and more recently macerated waste timber from the city's recycling depots," he said. "When mixed with the chicken manure the bedding can contain foreign matter and some toxins, but by using the forestry thinnings it makes the bedding free of contaminants."

Mr Outhwaite said the entire poultry industry in WA used roughly 100,000cum of bedding each year, with poultry sheds needing to be cleaned out eight times a year.

He said since their introduction two years ago, about 10 per cent of poultry farms were now using the forestry thinnings as bedding.

WA Biofuels was also investigating converting the thinnings into Biochar, carbonised in a purpose built furnace and then crushed, screened and mixed with the poultry manure in pellet form.

"We're hoping the Biochar mixed with chicken bedding and manure will improve the soil's carbon stocks and thus increase nutrient and water retention," Mr Outhwaite said.

"It would also make the manure more cost-effective by boosting its capacity to catch volatile nitrates, increasing its value to farmers."

Contract research provider Living Farm and its agronomist Richard Devlin were carrying out the trial.

"Many of our clients are farmers who see a large proportion of their annual budget spent on inorganic fertilisers including urea and sulphate of ammonia," Mr Devlin said.

"Analysis has shown the chicken manure has high levels of nitrogen and useful but low levels of phosphorous and potassium.

"It is therefore more suitable as a substitute for nitrogenous fertilisers and in this trial we decided to test it up against sulphate of ammonia."

In order to test the quality of the chicken manure, a trial site was established using 11 treatments replicated four times.

The treatments included varying applications of sulphate of ammonia, chicken manure and bedding, and Biochar. The trial was sown in June using Corack wheat at a rate of 75kg/ha.

Watching the results closely will be natural resource management group Wheatbelt NRM and its project delivery officer Tracey Hobbs.

"Farmers are becoming increasingly concerned that traditional fertilisers are not improving their soil health," she said.

"We're keen to see if this pelletised chicken manure could be a possible low-cost alternative supply of nitrogen, while also providing longer term benefits by conditioning the soil."