From fashion to field: cotton clothing shredded to help grow future cotton crops

There are lots of places where unwanted cotton clothes could go to escape landfill – the op-shop, a garage sale or turned into rags for tradies.

But what about shredding them and putting them back into the soil? And what if, in a world of perfect circularity, that soil was on a cotton farm?

Cotton Australia launched just such a trial on Wednesday to see if old cotton textiles – including sheets and worn-out coveralls from state emergency services – could improve the soils on a farm in Goondiwindi, Queensland.

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Farmer Sam Coulton and his grandson Harry spread two tonnes of shredded cotton on a paddock on Wednesday before the next cotton-growing season.

One big advantage that cotton products have over their synthetic, fossil fuel-based counterparts is their natural fibres are generally harmless and can break down in soil.

Last year, the industry’s Cotton Research and Development Corporation ran an experiment, burying 2cm-squares of cotton into moist Goondiwindi soil and then incubating it at 20C for almost six months.

Lab tests suggested the shredded cotton increased the bacteria and fungus in the soils, had no impact on the germination of seeds and all but the tightest woven cotton pieces broke down significantly in 24 weeks.

“We need to get smarter about how we reduce and manage waste,” said Dr Oliver Knox, a soil scientist at the University of New England who is being supported by the industry to supervise the trial.

“The big benefit here is diverting what currently goes to waste. There’s a risk that [the cotton items] go to landfill and produce methane, which is a damaging greenhouse gas,” he said.

He said because cotton fibres are made up from cellulose, it can become food for bugs and microbes in the soil, which means the “soil becomes more active”.

The cotton industry, alongside a circular economy consultancy Coreo, is watching the Goondiwindi Circular Cotton Project closely to see if it could be a large-scale solution for unwanted 100% cotton textiles.

Finding out what to do about synthetic threads, zips, tags, buttons and fabric finishes will be one of the jobs. For the trial, the cotton items were shredded at Sydney company Worn Up to resemble fluff.

Harry Coulton, 21, works on the farm called Alcheringa that’s been with the family since 1972. He said the cotton fluff had been mixed with a compost before it was spread across the paddock.

“We were naturally a bit worried but there’s a beautiful blanket over the ground now. It’s covered the ground nicely. We’re really happy with how it looks.”

The soil will be turned over – as is the usual practice – to help the cotton biodegrade before planting the crop. The coming season will be the first for three years where cotton could be planted.

“After the last three years we had this perfect flood giving us a great early start,” he said.

“We’re farmers and we are caretakers of the land and we have to give back what we take. With cotton we have to do our best to be sustainable for the future.”

Grandfather Sam said: “We grow it here and we should be able to bury it here with positive environmental and economic impact on the local community.”

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Brooke Summers, supply chain manager at Cotton Australia, said: “We know the cotton biodegrades really fast and the microbes and worms love it and that’s a really important part of our system for growing cotton.”

If the trial worked “we could deal with a huge amount of cotton material”.

“This is just one farm, but we have 1,500,” she said.

According to federal government data, an estimated 780,000 tonnes of textile waste is generated each year – or about 31kg a person. The recycling rate for textiles is just 7%.

Rebecca Gilling, deputy chief executive of environment charity Planet Ark, said throwing textiles in the bin meant throwing away a valuable material.

She said it was important to only buy what you need, to buy good quality classic clothes that don’t go out of fashion, and to find a second-use for anything that you don’t need.

“There’s no doubt with fast fashion now we see a huge amount being produced at low cost and low quality and often with mixed fibres that are much harder to deal with than natural fibre.”