Toil and Soil

Toil and Soil

Updated June 08, 2014 12:13:00

An increasing amount of food waste is being professionally composted and put back onto farms to improve the fertility of the soil.

Source: Landline | Duration: 16min 30sec

Topics: fertilisers, vic


PIP COURTNEY, PRESENTER: Most of the food our farmers grow ends up in the cities most of us live in and a lot of that food ends up being waste, the sort of waste that could be composted and put back onto farms to improve the fertility of the soil.

That doesn't happen as much as it should for a number of reasons, but as Chris Clarke reports, little by little there is progress.

CHRIS CLARK, REPORTER: If you live in the south-eastern suburbs of Melbourne, there's a good chance that some of this green waste came from your garden. And if you're from the western suburbs of Sydney, the contents of your green bin might end up here and be transformed into compost.

Dotted around all our big cities are waste recycling centres that take the waste we produce and turn it into something useful.

PAUL COFFEY, AUSTRALIAN ORGANIC RECYCLING ASSOC.: In 2012, we recycled approximately 5.5 million tonne of organic material. Of that, nearly 2 million tonne was green waste; so green waste compost that's collected by local government. Food waste was only about 350,000 tonnes, and that's where the opportunity lies for getting more material to process and more material out of landfill.

CHRIS CLARK: Recycling organic waste into compost instead of putting it in landfill cuts methane emissions, and methane's a much more serious greenhouse gas than carbon dioxide.

But there's another challenge the organic recycling industry wants to tackle. Most of the compost that's produced stays in our big cities. It goes back to our parks and gardens. We need to get more of it back onto farms.

PAUL COFFEY: We need to get people to see the benefits of recovering those waste products which come from agriculture. In other words, we grow food in an agriculture environment, we take the food to the city and then the waste is then taken to landfill. We need to take it back to the soil. We need to reinvigorate the soil in farms using that organic material.

CHRIS CLARK: Brendan Birmingham is a dairy farmer in Victoria's Gippsland. Dairy farming is all about grass in and milk out, the quality and quantity of feed is critical, and dairy farmers can quickly tell by the volume in the vat whether what they're doing is working.

BRENDAN BIRMINGHAM, DAIRY FARMER: We're milking 240 cows here, Holstein cows, on about 60 hectares. We were always predominantly spring calving, with a slightly higher stocking rate and we're sort of got more a bit of a shift to autumn calving, reducing the stocking rate a little bit more, chasing a slightly higher milk price and the farm will be just as profitable off less cows.

CHRIS CLARK: To do that, Brendan Birmingham has made some big changes. He's moved from perennial to annual pastures which means he re-sows about 80 per cent of his grazing land each year and compost's an important ingredient.

BRENDAN BIRMINGHAM: These paddocks were sown five weeks ago. They've had five tonnes of compost at sowing and three tonne of lime. This is all power harrowed in and then direct drilled.

CHRIS CLARK: He times his sowing to provide maximum feed for his cows when the milk price is at its highest.

BRENDAN BIRMINGHAM: By sowing annuals each year it's saved us a lot in water and gives us bulk and quality from mid-autumn right through until late spring, which are the critical months.

CHRIS CLARK: Across his farm, Brendan Birmingham set up 14 commercial trial plots with different combinations of fertiliser and compost to work out what's best. This is year two of the three-year trial, but he thinks he can already see improvements in soil structure.

After decades of grazing perennial pastures, his soils typically were heavily compacted. The compost encourages all sorts of good microbes in the soil, which in turn provide the sort of environment earthworms like.

BRENDAN BIRMINGHAM: This is typical of what we'd find.

CHRIS CLARK: A few worms and so forth?

BRENDAN BIRMINGHAM: The organic matter in the compost works into the soil.

CHRIS CLARK: And that's pretty important when you're trying to grow pasture in the way you're trying to do it?

BRENDAN BIRMINGHAM: Yep, you need quick establishment. We need those roots to get down, get established.

CHRIS CLARK: Dairy cattle are eating machines and milk production is closely linked to the quantity and quality of pasture.

Trial results so far suggest the compost is helping to grow a lot more grass.

BRENDAN BIRMINGHAM: All the compost plots, as against current practice, are growing about 24 per cent more over the seven-month period of the annuals and up to 31 per cent on the heavier plots.

CHRIS CLARK: This is where Brendan Birmingham's compost comes from. This composting operation is run by Gippsland Water, the local water authority. What goes into their compost might surprise you. The bulk of it's green waste and the first task is to decontaminate it.

An awful lot of things that aren't green at all end up in green waste bins - mainly plastics - and they have to be picked out by hand before any processing can start.

MARK HEFFERNAN, GIPPSLAND WATER: The big challenge worldwide with the amount of contamination that goes into green waste bins. Ideally we stop it at the source and I guess the way to do that is with awareness and people understanding where their green waste ends up. But we put in a lot of effort here to decontaminate it, because it does have an impact on the final product when we have plastic in compost.

CHRIS CLARK: Green waste can be shredded and composted in the open air, but some other wastes have to be handled under stricter rules. They can recycle all sorts of industrial and food wastes here.

MARK HEFFERNAN: We take a range of food waste here. Only recently we had a tanker full of chocolate which was unloaded here after a factory in Melbourne spoil. We've also had a truck full of pizza toppings arrive, including pickled onions and so on. So all we needed was bacon and we would have had the full show.

CHRIS CLARK: Oily water, other solutions and the like go into these settling tanks. The water can be drawn off and cleaned elsewhere. The solids can go into the compost mix. Some other wastes need to be combined first for easier handling.

MARK HEFFERNAN: In this case we've got a batch of spoiled or out-of-spec eggs. The waste here is fairly liquid and fairly soft, so what we're doing is putting it in the mixing pit and we'll mix it with green waste or sawdust or some other organics to make it spadeable and then we're able to scoop it out and put it in the composting process and in this case, being a proscribed waste, we'll put it in the in-vessels to pasteurise for three days.

CHRIS CLARK: Proscribed wastes are pasteurised in covered vessels to kill pathogens.

MARK HEFFERNAN: We compost a range of proscribed wastes. The majority of our waste is grease trap and dairy waste, however we also take contaminated soils, car wash waters and other food wastes and that produces a very good compost once it's been pasteurised.

CHRIS CLARK: In fact, just about anything can be recycled.

MARK HEFFERNAN: Recently we had crude oil washing up on the local beach and we're able to take the sand with the oil component and we've actually put that through the vessels and pasteurised that and now it's maturing on the hard stand.

The hydrocarbons are suitable for the composting process and do produce a high nitrogen level once matured.

CHRIS CLARK: The other big component in the compost is biosolids. That's the solid human waste left over from the sewage treatment process. A lot of it now goes to landfill, but by including it in their compost mix, Gippsland Water has found a productive way of recycling it.

MARK HEFFERNAN: In our final product, the green waste makes up about 70 per cent of the content and the remaining 30 per cent is made up of the biosolids and also the food waste such as dairy waste and egg waste and also oily waters and the contaminated solids that we're able to process here.

CHRIS CLARK: Making compost is a precise process. The material in these windrows has to be turned regularly and kept within a certain temperature range to promote the microbiology that ultimately turns it into a stable product.

MARK HEFFERNAN: So this compost has been through a 12-week cycle. It started off as a raw product and did its four weeks pasteurisation and then spent eight weeks maturing. So we've got a mature compost here that is nice and stable, with very low odour, nice dark colour and it's nice and fluffy and moist.

CHRIS CLARK: It's now ready for the farm. And luckily for Gippsland Water they have their own farm enterprise onsite, where they've been able to test their compost over a number of years.

Jono Craven manages their ag-business. They run a substantial beef cattle herd and crop between 600 and 700 hectares.

JONO CRAVEN, GIPPSLAND WATER: So the paddock we're in at the moment, Chris, is canola, so we're growing around 150 hectares of canola as part of our rotation. Which includes normal cereals - wheat, barley, triticale and some fodder crops for hay as well.

CHRIS CLARK: Will all those get a compost treatment before they go in?

JONO CRAVEN: They will. So everything will get that three tonne to the hectare of compost, basically in front of the planter, so it's spread and incorporated pre-planting.

CHRIS CLARK: After several years routinely spreading compost over their cropping land and pasture, Jono Craven says they're getting measurable improvements in soil composition.

JONO CRAVEN: What we're seeing with compost over the last couple of years is that, in this paddock especially, we've been able to move our pH by nearly a point, and we've moved organic matter by 1.5 per cent in this paddock. So, we've moved it from about 1.6 per cent to around 3 per cent, which is a really good achievement in a short time frame and also in a dry land situation as well.

CHRIS CLARK: Just as it's taken time to refine their compost product at Gippsland Water, so the benefits of composting take time to reveal themselves.

JONO CRAVEN: Compost in nature is an organic, sort of slow-release product, so to stop one system completely and start on a compost system, you need to transition into it slowly. But I'm hoping within three to five years that compost will meet all of my needs in cropping. Now it's essentially meeting all my needs in pasture and livestock. So there's not too many inputs going into that system at all, apart from compost.

CHRIS CLARK: Having your own farm to use as an experiment is probably helping to sell their product to the locals. Fertiliser distributor Damien Gibson thinks so.

DAMIEN GIBSON, GIBSONS GROUNDSPREAD: The main farmers utilising the products at the moment are dairy farmers. They seem to have a bit more understanding and awareness of their fertility needs and also the ability to take a few risks in their business. So for farmers around us, it's very much been the dairy market.

CHRIS CLARK: Even so, he sees compost complementing synthetic fertilisers, not replacing them.

DAMIEN GIBSON: The main reason probably is there's not enough is the actual fact. So I think integrating it as part of the farming fertiliser program is where it's going to be. So predominantly, farmers are putting it on one to two times a year and then topping up with normal traditional fertilisers, as feed requires. So I think that will be where it fits in long-term.

CHRIS CLARK: But getting more compost onto more farms has its challenges, as avocado grower Steve Marshall can attest.

He grows avocados on the Mornington Peninsula, a bit over an hour from central Melbourne. He's just doing a second application of compost and thinks it's ideal for the shallow root system of the avocado tree.

STEVE MARSHALL, PENINSULA AVOCADOS: First of all you can see it's still nice and moist in there and there we go, the avocado roots have already found it and this has only been out maybe 10 weeks and they've already started heading up into it. Being surface root structure, very fine, fibrous root system, they basically go hunting for where the organic material is decomposing and that's where they're feeding.

CHRIS CLARK: But getting to this point has had its trials. Over the years, he's found big variations between composts and contamination's been a problem.

STEVE MARSHALL: One product we got once, we got a load of bricks with it as well and we still have the bricks sitting in the orchard because no-one's really got round to picking them up yet, but they're out of the way at least. Other products can be water - during the manufacturing process quite saline bore waters can be used. So all of a sudden you might be thinking you're adding a really good product but actually it's really salty, which for us with the avocados is a big no-no. But we know with this stuff it's pretty much right.

CHRIS CLARK: Like most users of compost, Steve Marshall stresses it's just one ingredient in producing a healthy and productive environment for his trees.

STEVE MARSHALL: We're talking about gains that are different to the application of commercial fertilisers. This is about going into the soil itself and looking at the big picture, the soil microorganisms, and also the mechanisms that can help the other fertilisers that you apply being taken up and also held in the soil.

CHRIS CLARK: Transporting compost is expensive. Even close to Melbourne and the source of suppliers, as these orchards are, transport costs more than the product itself. And then there's the cost of spreading it.

STEVE MARSHALL: When it comes to spreading it, that's always been an issue too. The company that we're dealing with at the moment, they've now built their own spreader. They recognise that there was a gap between the farmers wanting to use the product and them trying to sell the product.

CHRIS CLARK: Increasing compost's appeal to the broader farming market is the industry's main marketing challenge.

SIMON HUMPHRIS, ENVIROMIX: A lot of farmers see the benefit. They know what the benefits are, but there's also a massive number of people that just don't know it. We need more of us to go out there and push this product to really get it out there and our industry is starting to focus more on that marketing aspect. I still think the feet on the ground with the farmer is the key.

CHRIS CLARK: Most agree the urban market for compost is fairly saturated. If there's to be growth, then greater use in broadacre agriculture seems a logical path.

This is partly driven by necessity. State and local governments generally want to recycle more waste, including all the food waste that now goes mostly to landfill.

Paul Coffey runs the Organic Recycling Association, which represents commercial composters.

PAUL COFFEY: Most of us now recognise that putting those materials into landfill creates methane gas which has got 21 times the effect on the greenhouse as what carbon dioxide does, so it is a bad thing. The whole circular economy - that is, of taking that nutrient from the soil and the biology from the soil, and taking it to the city, we need to recognise that taking it back is an important part of sustainability.

CHRIS CLARK: Farmers will buy more if the price they pay reflects the true cost of recycling, meaning all of us must pay.

PAUL COFFEY: What we've done in this country, is the farmers have actually lost the natural capital in their soil, the natural capital being that organic matter, and being that carbon that was in their soil. To recover them means we have to process them, and take them all the way back. And that has never ever been factored into the price, or the value, of a product.

CHRIS CLARK: Gippsland Water has found a sweet spot, which allows it to recycle waste into a product that local farmers will pay for. It can be done.

MARK HEFFERMAN: Well currently we're pushing out about 1,200 tonnes of compost per week, and that's going straight to farms. We see over the next 12 to 24 months that we could double our production and all of that will be used by farmers. So we think that there's a pretty bright future in our compost.

CHRIS CLARK: It's giving people like Brendan Birmingham greater choice about how they run their farms.

BRENDAN BIRMINGHAM: We're getting paid a higher price for our milk, with more autumn milk, more off-season milk, and being able to sustain production much better through the autumn and winter months, due to having more high-quality pasture in front of us.