Compost Turners – A DIY Alternative
Moving to Compost
Article by Michael Grebert, BMRG Regional Agricultural Landcare Facilitator
5 July 2022
As well as market disruptions caused by Covid19 and volatile weather events, agricultural input costs have soared in the last year, particularly fuel and synthetic fertilizers.
The war in Ukraine has restricted fertilizer supply chains through Russia, China and the Middle East.
Agricultural producers who’ve become reliant on synthetic fertilizer are looking for alternatives to remain viable and improve resilience in the face of external shocks and rising production costs.
One response becoming increasingly attractive is using compost to replace at least part of, or supplement fertilizer application regimes.
Unlike the dramatically increased crop yields seen with the advent of modern fertilizer application regimes, which spurred their widespread use in industrial agriculture, the benefits of compost are much more subtle, at first. With a commitment to ongoing application, soil carbon increases incrementally and associated long-term benefits accrue, making agricultural production processes increasingly resilient.
Compost also reintroduces bioorganic structure in soils. It promotes beneficial mycorrhizal fungi which grow in association with plant roots, greatly increasing their absorptive area, and nutrient access. Living soil has better moisture retention, improved drainage, aeration and more stable PH levels.
Other resilience benefits of compost include fewer plant pests and diseases, reduced runoff, erosion damage, and nutrient loss from extreme weather events.
Synthetic fertilizers rely on petrochemicals in their production, so replacing them with compost also decreases the carbon footprint. This is important to consider when assessing overall farm performance.
So, why isn’t everyone using more compost? Increased demand for compost has seen prices rise and the availability of suitable green composting material becoming relatively scarce. Some agricultural producers, such as local macadamia growers, are self-sufficient in terms of composting material. Others rely on a supply of suitable clean raw materials from third parties to make their own. There are some regulatory considerations to consider.
Once any required permissions are in place, and a reliable source of compostable material is secured, making good compost involves diligent temperature and moisture control, as well as regular turning.
Turning compost by mechanical means usually involves a dedicated compost turner. These are expensive, and again, demand is increasing, further inflating the price of this machinery.
According to Future Market Insights, sales of compost turning machines rose at a compound annual growth rate of 3.2% from 2013 to 2021; the global market attaining a net worth of US$ 116 million in 2021. Demand for organic fertilizer turning machines is expected to rise through 2028 as people become more aware of the benefits of organic farming with compost turning machine demand estimated to rise at a compound annual growth rate of 3.6% from 2022 to 2028.
So, where does that leave the average farmer? Many farmers possess the skills, creativity and at least some of the materials to make a DIY compost turner a viable alternative to purchasing a new or used machine. This may not apply to every agricultural producer, so it’s up to individuals to make their own assessments.
Local farmer, Tony Chapman has done just that. He’s also been generous enough to share his key design features to assist those who may also wish to build their own compost turner.
Raw composting material typically arrives at composting sites by truck. Wind rows of compost material typically spread to roughly 4 to 4.5 metres at the base width as they fall from transport truck beds.
So, the rotor which turns the compost needs to be ideally 4-4.5 metres wide to match the profile of the wind row. Smaller rotors require additional manipulation of the windrows to work efficiently.
At this width, a tractor with PTO and at least 175hp is required to drive the turner at 0.6kph – 0.8 kph. A hydraulic reduction system is used to reduce travel speed to this rate.
Other dimensions are 1.6 metres deep, 5.2 metres from outside tyre to outside tyre, and 3.5 metres total width, to enable road transport as required.
The teeth on the turner are replaceable wear points made of used, repurposed rotary hoe blades. They are cut off and match drilled to holes on the drum stubs to enable easy replacement.
For further details, and to see the machine in action, go to Chapman Ag – Home | Facebook
So, if you can’t do it any other way, you may be able to do it yourself. Please do your own research regarding approvals, costings and risk assessments as required. Feel free to contact me with any comments, ideas or questions.
Regional Agriculture Landcare Facilitator