ABOVE: A key learning distinction was made between compost – which has been matured or cured for over 16 weeks – and ‘hot mix’, which commonly undergoes only the first pasteurisation step of composting and is then used for further composting activities.
Recently, I headed to Tocal to hear from global experts on the latest on a common agricultural practice – composting.
The day was organised as part of the Smart Farming project Pilot to Paddock Innovative on-farm water, energy and nutrient technologies and practices for Australian dairy, egg, pork and cropping industries — a build off the partnership created through the National Agriculture Manure Management Program.
The program covered a broad range of topics – from barriers and opportunities for on-farm composting, rules and regulations to setting up a composting operation.
A mix of local speakers was also present – Kevin Wilkinson, Janine Price and Johannes Biala, as well as two international speakers.
It could be argued that the intensive industries have been composting more material than commercial food and garden composters, however, it is usually a secondary activity to the farm business, so there are lessons and advancements to take from this sector.
A key learning distinction was made between compost – which has been matured or cured for over 16 weeks – and ‘hot mix’, which commonly undergoes only the first pasteurisation step of composting and is then used for further composting activities.
Of interest were two talks from US speakers – from the State University of New York and principal editor of the 900-page composting handbook Dr Robert Rynk and Matt Cotton, who owns Integrated Waste Management Consulting and is a lead educator for the US Composting Council.
As US agriculture is more land constrained than Australia, there are logistical challenges for the US to manage waste.
This has led to farmers and businesses becoming experts in and highly proficient at composting, with sites having composting windrows down the sides of internal roads.
Other innovative approaches that were shared included heat recovery from composting static piles, which is used to heat greenhouses.
This uses forced aeration under static piles with pipes and blowers to speed up the process, reducing the number of turns required.
As with most farming ventures, whether composting will work at a site comes down to some fundamental questions:
- What are you going to compost
- How much
- Who is going to compost it
- Where are you going to compost it
- What are you going to do with the compost?
Mortality composting was also explored, including lessons learned from mass mortality composting in the US.
This included a reminder that for windrow composting, a minimum of five turns is required to ensure mortality breakdown.
Recently, NSW Department of Primary Industries – supported by funding from Australian Pork Limited – looked at the possibility of grinding a carcass first, to reduce breakdown times.
More work is planned in this space to assist in preparing for a mass cull event, particularly in the event of emergency animal diseases.
The workshop ended with an overview of the nutrient calculator for organic amendments.
This aims to integrate nutrient supply from compost into farm nutrient budgets and seeks to gauge if compost could replace mineral fertilisers.
The researchers are currently seeking feedback to improve the tool.
To explore this tool, visit oa-nutrient-calculator.netlify.app
