Closing the ‘green city loop’ – green organics for urban green environments (MT13042)

What was it all about?

An earlier study (HG10025) found that green waste from cities and farms can be converted into biochars that could be used to enhance on-farm productivity.

This project took the next step towards commercial product development by validating with growers the usefulness of products for the turf and nursery industries.

These industries were chosen because products can readily replace or enhance existing amendments or media additives, transport costs can be kept low and the ‘green city loop’ can be closed since greenlife in cities means more organics for more greenlife.

A trial was set up with the Australian turf industry to test the rate of plant establishment using two types of green waste biochars. The site used industry best practice, including fertiliser co-application with biochar, since this is required for optimal plant performance. Plant health and growth rates were measured.

Similarly, a trial was set up using two types of biochar with the nursery industry, replacing unsustainably harvested peat products in growing media. Measurements characterised plant establishment and seedling vigour at one and two weeks after germination through shoot and root length and dry weight recordings.

In a third research study, a long-term field trial at a commercial blueberry farm tested the usefulness, logistics and practicality of organic products for the perennial fruit industry, documenting crop performance, yield, soil health and carbon sequestration over consecutive seasons and years.

Key findings:

• For the turf industry, biochar showed good potential as a product for landscaping if mixed into growing media or soil prior to laying turf
• Biochar made from Brisbane city’s green waste or farm trash was an effective component of potting media for container plant production, with the best products accelerating vegetable seedling growth while being economically viable and environmentally sustainable
• Compost and biochar, applied together, improved blueberry yields and soil health over the long term.

Overall, the results showed that biochar products, if optimised for each industry, promise greater productivity, environmental sustainability and expanded market opportunities.

Trials were also directly relevant to growers who sow nursery-raised transplants or plants, such as the Australian vegetable industry, fruit and ornamental tree and shrub growers, landscapers and others.