How farmers can give agricultural plastic waste the flick

Published: February 2020 I By: Jill Griffiths

From silage wraps to ag chemical bottles, farmers can be big users of single-use plastics. Now cutting-edge NSW programs are finding new ways to deal with waste.

Landcare’s Phoebe Gulliver and farmer Cameron Lowen collect silage wrap. Source: ABC Rural. 
THE problem with single-use plastic is never far from the news. But what isn’t well known is that farmers in the NSW Murray are leading the way in coming up with solutions to deal with their plastic waste.

In 2017, Holbrook Landcare Network (HLN) responded to a call from producers in the area wanting to find a better, more ethical way of dealing with on-farm plastic waste. It placed skips at landfill sites in the Greater Hume Shire, where producers can drop off bags of their plastic waste – mainly, silage wrap and baling twine. 

Woomargama beef and sheep farmers Simon and Liz Plunkett produce 150 to 200 bales of tube-wrapped silage each year and have happily got on board the recycling program. Liz says the silage wrap previously made a mess on the farm. “It would wrap around electric fences, causing them to short, so then the cattle would get mixed up,” she says. 

Simon adds that the recycling service provides a much better alternative to burying or burning the plastic.

HLN project officer Phoebe Gulliver explains how the program evolved. “We got funding for a pilot project from Murray Local Land Services,” she says. “HLN was then funded by the National Landcare Program to expand the project within the Greater Hume Shire.

“We were originally planning to send the plastic waste to a recycling operation in Melbourne, however we discovered [plastics recycling company] Plastic Forests were setting up their recycling business in Albury, so we partnered with them to deliver our project outcomes. The project aimed to find an alternative to burying or burning the plastic waste generated on farms.

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“The program is quite specific in terms of the type of plastic collected,” Phoebe says. “It’s about thin plastic wraps at this stage.”

There is no doubt that plastic is useful on farms – among many other things, it is used to wrap silage, in twine to bale hay, for containers to hold chemicals and as mulch under vegetables. All of these are single-use applications – the plastic is used once and that’s it. 

The wonderful thing about plastic is that it is durable and lasts a long time. The terrible thing about plastic is that it is durable and lasts a long time. So the very thing that makes it useful also makes it problematic. 

It’s also important to remember that there are many different kinds of plastic – there are hard and soft plastics, bioplastics and petroleum-based plastics – and they carry different recycling numbers depending on their constituent chemistry. Then there are various descriptions of biodegradability.

Plastic Forest’s David Hodge at the distribution centre. Source: Newspix. 

Plastic Forests is one of a few businesses recycling plastics in Australia. Managing director David Hodge says the business focuses on the “difficult” plastics – the soft plastic films that are hard to recycle. “We started doing the R&D about 10 to 12 years ago and deployed the factory in 2011,” he says. David describes the early years as “horrendous” with “a lot of system failures and learning” before they “fine-tuned the process and sorted the problems out”.

“Then, in 2018, China exited the [recycled plastic importation] market. It took away any value in the plastic,” he says. “So we had to reframe the business again.”

But David is focused on a bigger picture than whether China is in or out of the market. “As a nation, our waste is growing much faster than our population,” he says. “What would have happened if the Romans had invented plastic? What would the world look like now? It would be a mess. We all know that this waste thing is wrong.”

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He points out that there are 300 different types of plastic in the market. Recycling requires the right products to be re-manufactured from the plastic, and then a market to be found for them. Plastic Forests currently produces garden edging and posts, electric cable covers and wheel stops, as well as resin, which goes to manufacturers for use in other plastic products.

“I’m really excited about the products we are now offering and have in development,” David says. “We have a plant that can produce 5,000 tonnes a year, but we’re not producing anywhere near that yet.”

As HLN’s Phoebe Gulliver puts it, “Basically, it’s not recycled until someone buys those recycled products. It comes down to David having demand for the end products he can produce.”

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For farmers and others interested in supporting recycling programs, that means getting on board and buying products made from recycled plastic where they are available.

“It will be support and demand for that end product that will ensure the project continues into the future. People are definitely interested. It’s about having somewhere to send it. Transport is a limiting factor,” Phoebe says. “We’d like to help other groups jump on board and follow the same process that we have put in place.”

An agricultural mulch film from Bioplas designed to break down completely in the soil after the crop cycle. Source: supplied. 

A NSW Environment Protection Authority (EPA) spokesperson says the EPA strongly supports community initiatives such as the one at Holbrook and offers grants to support recycling programs. “We would encourage farmers to look at recycling their plastic waste,” the spokesperson says.

Phoebe believes that some sort of a tax or levy on the purchase of silage wrap would help shore up the process. “In reality, something like that will have to kick in,” she says.

David agrees there needs to be a bit of a push, if not a shove, to move things along. “What is missing from this whole waste discussion is the sense of urgency,” he says. “What has happened is that the economics have changed. 
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“If I’m a farmer and I take my 10 tonnes of silage wrap to the local landfill, it’s going to cost me $2,000. It’s easy for me to think that if I take it to landfill, it’s just going to be buried, so if I bury it down the back of my paddock, it’s just the same. Or if it’s in a pile and a little grass fire starts and the silage wrap goes up in flames… it will also disappear! There’s a financial disincentive to do the right thing.

“We don’t want farmers burying it – silage film buried 40 years ago has been dug up and looks just like the stuff from today. If we burn it, we release all sorts of toxins, such as dioxins, and nature can’t deal with them either.”

Plastic fertiliser bags are compressed at a recycling factory. Source: Holbrook Landcare Network. 

While the EPA does not encourage farmers to burn or bury plastic waste, there is no blanket ban across the state for such disposal of plastic waste generated on farm. However, these practices are banned in specific locations and under certain conditions, so farmers are advised to consult local authorities and environmental regulations before burning or burying plastic waste. Recycling is encouraged where possible.

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“It’s time for a soft plastics muster. We have created stuff that nature can’t break down. We need to deal with it,” he says.

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Australasian Bioplastics Association president Rowan Williams would prefer people were more circumspect when talking about biodegradable plastics. “It is completely meaningless to talk about biodegradability unless you talk about a time frame and how it happens,” Rowan says. He points to the Australian Standard AS 4736-2006 Biodegradable Plastic, with its associated tests for biodegradation. “It’s either pass or fail. You meet the Standard or you don’t.”

Rowan says there are two broad families of bioplastics: those that can be composted or fully biodegraded and those where the carbon from oil is replaced with carbon from a renewable source, such as cornstarch. “Once produced, the second group of bioplastics behave exactly like petroleum-based plastics,” he says. 

 “The difference is that they have a zero-carbon footprint because they are produced from plants that are regrown. They are designed to go into the conventional plastic recycling stream.” 

If plastic doesn’t biodegrade fully and isn’t recycled, it can break down into tiny fragments called microplastics, which contaminate the ocean and land. They have also been found in biosolids from sewage treatment plants. When those biosolids are spread on agricultural land, they return valuable phosphorus, nitrogen and other nutrients to the soil, but they also bring with them microplastic.

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Kelly Hopewell, chair of the Australian & New Zealand Biosolids Partnership, says the sewage treatment plants have screening processes that take out large pieces of plastic, but the microplastics do find their way through and into the biosolids.

“Most of the microplastic in sewage comes from clothing,” she says. “We don’t know exactly how much of an issue it is. It needs more research. We need international standardisation to deal with it. While we don’t want to see our biosolids put on agricultural land if it creates a problem, I think at this stage it is valuable in terms of nutrient and carbon recycling to use biosolids on agricultural land rather than incinerating it.”

Problematic plastic mulch films create potential for biodegradable solutions

CSIRO scientist Dr Keith Bristow says plastics generally are a problem in agriculture. Dr Bristow is particularly focused on plastic mulch films, which have proven benefits in terms of crop yields.

“China has used plastic mulch films for more than 40 years,” Dr Bristow says. “They have proved the benefit of using petroleum-based plastic to suppress weeds and minimise soil evaporation, with yields increasing by as much as 40% in terms of water-use efficiency and crop yields. 

CSIRO scientist Keith Bristow is working to develop a sprayable, biodegradable polymer film. 

“But the plastic product that has been used doesn’t biodegrade. It fragments. And in the fragmentation process, it releases toxins and heavy metals. Some of these plastics are incredibly strong – and more than likely will be around for centuries.”

Chinese researchers report that plastic film coverage in Chinese agriculture has now reached about 20 million hectares and over one million tonnes of plastic. They state that “large amounts of residual plastic film have detrimental effects on soil structure, water and nutrient transport and crop growth, thereby disrupting the agricultural environment and reducing crop production”.

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Dr Bristow points to the Chinese experience as being an example we don’t want to follow. Australia needs a better solution. He is now on a mission to develop a replacement product – a sprayable, 
biodegradable polymer film. While the chemistry is yet to be finalised, he is convinced that within five years there will be such a biodegradable film in use in agriculture around the world. 

Others are taking a different approach to tackle the same problem. Rowan Williams of the Australasian Bioplastics Association says the chemical company he works for, BASF Australia, has a mulch film product that is certified soil biodegradable. “It’s a bit more expensive than conventional PE [polyethylene], but after the growing season it can be ploughed in and it will completely break down into its elements,” he says.

A study that traced the carbon from the mulch film found that after six weeks it had all been consumed by bacteria, he says, and all ended up either as soil carbon or as carbon dioxide gas (with 13% emitted as carbon dioxide).

Other companies are also working towards producing certified biodegradable mulch films. Anthony Muscat, an agronomist and vegetable grower based in the Sydney Basin, trialled a prototype AgNova biodegradable mulch film a few years back and thinks it would be a good thing if it could be made to last a bit longer. “It started breaking down after about 12 weeks, which was fine with zucchinis as long as we got them in the ground as soon as the mulch went down,” he says. 

“The concept of it is good. With conventional plastic you always end up with bits of plastic left everywhere no matter how hard you try to pick it up.” 

Anthony says disposing of conventional plastic mulch is problematic, with many landfills refusing to take it and few options available for recycling. Yet the fact remains that plastic mulch is useful in horticulture to retain moisture and as a weed management tool, providing options other than continuous herbicide use.

But the potential problem with certifiable biodegradable plastic is the very thing that makes them useful – they don’t last. It’s the reverse problem of durable plastics. They don’t necessarily work well for strawberries or other perennials, and they also won’t work for applications such as silage, again, because they biodegrade before the job is finished. 

These applications require long-lasting plastic. The question then, is what can be done with it after it has been used?

Recycling program success - drumMUSTER

A recent on-farm collection in the NSW Riverina, organised by drumMUSTER. The program arranges on-farm collections on a case-by-case basis where there is a minimum number of 400-500 drums to be collected. Photography by Tanya Ginns. 

Since it began Gunnedah in May 1999, drumMUSTER has grown into a successful national collection and recycling program. It has now picked up more than 34 million drums nationally, of which over 10 million have been from NSW.

It’s run by Agsafe and funded by a levy of 6c per litre/kilogram, which is collected via the agvet chemical manufacturers and passed on to end users as the final price. The program is responsible for recycling about 50% of agvet containers sold in Australia. 

Agsafe general manager Dominique Doyle says drumMUSTER has now diverted 38,784 tonnes of plastic waste nationally from going to landfill, or being buried or burned on farms.
“A good thing to understand is that the plastic that we collect and recycle stays in Australia and is recycled back into product,” she says. 

Agsafe general manager Dominique Doyle. Source: supplied. 

Recycled plastic from the program is made into goods including wheelie bins, fence posts, irrigation pipes, underground cable covers, bollards and barstools.

“Community groups get 25c per container for collection and that equates to over $487,723 put back into the NSW community since the program’s inception.”

7 ways to reduce plastic use on farm
  1. Buy products in reusable, returnable bulk containers where possible.

  2. Rinse and return agvet chemical drums through drumMUSTER.

  3. Seek opportunities to take plastic film and twine to collection points.

  4. Investigate use of certified biodegradable plastics where appropriate.

  5. Buy products made from recycled plastic where available.

  6. Where recycling is not available, dispose of plastic waste appropriately, ideally at a registered landfill site. 

  7. Do not burn or bury it on farm as smoke from burning plastic may be toxic and carcinogenic.

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