About Composting
Approximately 60% of the rubbish Australians put in the everyday mixed-waste ‘garbage bin’ could be put to better use in the garden as compost and mulch or could be returned to agricultural land to improve soil quality.
Alarmingly, such a huge amount of organically-active material buried ‘anaerobically’ (without air) in landfill causes over 3% of Australia’s total greenhouse gas emissions annually through the production of methane gas (which has 25 times the global warming potential of carbon dioxide).
Direct sequestration of this organic material greatly increases carbon in the soil reducing the effects of climate change. In addition to this, using compost on land reduces the need for water by an average of 30%, greatly improves soil quality and helps grow beautiful veggies and fruit!
Look below for more information on Home Composting, On-farm Composting and Commercial Composting.
Home Composting
Each year over half of our household garbage is made up of food and garden waste. Most of this organic waste can be recycled by composting it.
By turning food scraps and organic garden waste into compost you can:
- Improve soil quality and garden vitality by releasing the rich nutrients in the compost into your soil
- Recycle valuable nutrients and reduce the use of artificial fertilisers
- Prevent greenhouse gas emissions and reduce the amount of organic waste going to landfill
- Improve water savings
- Save your money
What to add in your compost bin:
Vegetable and fruit scraps, vegetable oil, prunings and lawn clippings, tea bags and coffee, grounds, vacuum dust, shredded paper and cardboard, used potting mix, egg shells, flowers.
What not to add in your compost bin:
Meat and bones, dairy products, diseased plants, metals, plastic and glass, animal manures, fat, magazines, large branches, weeds that have seeds or underground stems, sawdust from treated timber, pet droppings, synthetic chemicals.
On-farm Composting
Throughout the 20th century chemical fertilizers have been used to increase and maintain production, however they cannot replace the loss of organic carbon in the soil, are increasingly expensive and, ultimately, deplete soil nutrient levels.
What compost provides to farms:
- Both the nutrients and organic carbon necessary to rehabilitate degraded soils and to support production in intensive farming systems
- Reduce the need for irrigation water
- Reduce chemical fertilizers
- Increase production, particularly where soils are already degraded by many years of farming
- Increase overall soil quality
- Save money
Some farmers make their own compost using straw, manures, recycled organics and other readily available agricultural wastes or local by-products of food processing. They manage the composting process using readily available farm machinery and apply the compost to their own land. Others however are purchasing specially designed machines called ‘windrow turners’ and monitoring equipment so they can gain greater control of the composting process and produce high quality composts called ‘humic’ composts.
On-farm composting is well suited for rural and semi-rural areas where this concept is able to deliver significant benefits for waste management, the environment, the community and farmers.
In Australia, on-farm composting is still in its infancy but is gaining momentum. Potential offsets of the carbon tax may be available in the future.
Commercial Composting
Many councils around Australia offer a collection service for garden materials. This material is professionally processed into compost-based products such as soil conditioners, mulches, garden soils, top dressing soils and potting mixes.
New products are continuously being developed for environmental applications such as erosion control and storm water treatment. Tailored products are also available for agricultural applications such as fruit & vegetables, grains, pasture improvement and forestry.
There are approximately 140 businesses around Australia recovering more than 5.2 million tonnes of organic wastes and turning them into useful products and services each year. The remaining recycled organic material is either applied directly to land or used to generate heat or electrical energy. Collectively these commercial organic recycling businesses are called the Recycled Organics Industry. The peak body representing the Recycled Organics Industry nationally is Compost Australia.
The Recycled Organics Industry uses a wide variety of organic materials to make their products. In addition to the lawn clippings, cuttings, branches and leaves that are collected from your home they also recover the sludge from sewerage treatment plants, manures, wastes from the forestry industry, food wastes, grease trap wastes and many other organic by-products that would otherwise go to waste. With the right technologies and process controls nearly any organic waste can become a resource.
The Recycled Organics Industry is also developing innovative uses for compost. From liquid compost extracts (known as ‘compost tea’) that suppress disease in grape vines to compost erosion control ‘blankets’ that prevent erosion in road cuttings. Even storm water can be bilogically ‘cleaned’ with compost media before being released into the ocean, as is currently the case at North Steyne Beach in Sydney.
