Crafting High-quality Compost For Agriculture

Greg Watts: The best thing about some of our feed stocks if I look at waste grain, for instance, that we bring in, it actually creates that circular economy story. You're taking grain or cereal waste, you're composting it and returning it back to a farmer who's then going to grow the next crop of oats all wheat.

Lachlan Jefferies: The challenge of urban recycling, or the FOGO bin, is the vast majority of the community gets it and is engaged in, but we do get elements of items that aren't compostable, like items that are around the garden. So someone's bought some mulch bags and emptied out the mulch and put the bags into the green bin. Some of those mistakes, we get lots of garden tools because they've got lost in a pile of leaves. If we can limit what we purchase and we're limiting what we're throwing away. And understanding that your green bin goes to make great compost or mulch, so keep it clean.

Craig Allen: G'day, I'm Craig Allen. And you've been listening to the Healthy Soils Podcast, a series about compost and how it can help create healthy soils that then grow the food we eat in Australia. The purpose of this podcast series is to help make the connection between organic waste generation and food production. And to inspire you to think about what you can do when it comes to organic waste, including food waste and compost.

On this journey, we've been talking with farmers, composters, and soil experts about the role we can all play in getting organic waste out of landfill, and instead turned into compost. Because healthy soils produce healthy crops, which lead to healthy humans and animals. We start by talking with Greg Watts from C-Wise, a compost and soil amendment company in Western Australia. He spent years working on innovative solutions to recycle organic waste into high-quality compost, helping farmers improve their soil health and productivity. Greg focuses on creating products tailored to the diverse needs of Australian agriculture, from broadacre cropping, to vineyards and orchards, he introduces us to the need for clean, high-quality compost. And later, their process to achieve that quality and how they're driving change to support sustainable farming.

Greg Watts: What's special about our compost is that we're aiming for a carbon percentage upwards of 40%. So, the more organic carbon we can have in our compost, the better off we are. Which is why some of our by-products that we use to make the compost, we have to actually pay for, which is unusual in a composting environment in Australia. But we know that gives us clean, high-performing, high-carbon feedstock, which is what we want to see and process through to high-carbon, high-performing composts. Green waste coming from a verge collection or self- haul to the local landfill, or waste transfer station or whatever, is traditionally cleaner than what other people you're talking to in the East Coast are probably experiencing coming out of the third bin. And the food organics that we are currently taking are commercial collections. And because you're dealing directly with I guess the producer of that byproduct, we have a very good relationship around what contamination is acceptable and what's not.

When I think about my customers in the broadacre agricultural sector, they're really concerned about their clean green Australian brand. As they should be, because they're exporting their product based around the fact that it's produced in clean green Australia. If I were to talk to them about plastic contamination, their appetite for contamination of my compost is, "Well, I don't want any. I want zero plastic, I want zero glass." There's a real concern there that we need to work very hard to educate that public to make sure that they don't inadvertently or purposefully contaminate those bins. Because if we can't sell the product at the other end, then effectively all we've done is generate another waste.

Craig Allen: Now let's turn to Lachlan Jefferies, a compost expert and passionate advocate for sustainable recycling practises. We've spoken to Lachlan in previous episodes, and you can get information on those in the show notes. Like Greg, he's equally committed to reducing or removing contaminants in urban recycling, or in a food organics and garden organics, or FOGO bin.

Lachlan Jefferies: The challenge of urban recycling, or the FOGO bin, is the vast majority of the community gets it and is engaged in, but we do get elements of items that aren't compostable, like items that are around the garden. So someone's bought some mulch bags, and they've emptied out the mulch and put the bags into the green bin. Some of those mistakes. We get lots of garden tools because they've got lost in a pile of leaves. Soft plastics, a lot of single use items are common contaminants in both the yellow and the green bins. They're physical elements. There's also the things we can't see, and that's where the testing comes in. We are constantly testing, whether it's persistent herbicides and those elements, ensuring that they're in appropriate ranges. And that's a test in their lab. And then separately here on site at Jefferies we have a growing lab, so we'll do our own growing trials to ensure germination and those kind of things.

There's a lot of different things that householders can do, and they are doing, is getting engaged in that whole recycling system. A lot of councils provide information on their website. And the choices we make, we still have the challenge. Biodegradable is a word that us composters wish would be banned, because everything's biodegradable, but not in a timeframe in a commercial composting system. The Jeffries Recycled Organics Sorting System is designed to try and pull as much of those elements out. Just on that point, it is not perfect, so we really appreciate that the community puts their best foot forward and the best material in their green bin, if we can limit what we purchase and we're limiting what we're throwing away. And understanding that your green bin goes to make great compost soil mulch, so keep it clean.

Craig Allen: It's clear that processing FOGO bins involves a lot more complexity than many realise, and facilities need help from households to keep their FOGO bins organic. Now, let's hear from Steve Nicholson, a broadacreage farmer and experienced agronomist who we spoke to in previous podcasts. From his farm near Forbes in New South Wales, Steve gives an emphatic perspective on the growing industry's need for uncontaminated compost.

Steve Nicholson: Quality is everything, I've said this so many times. You want a product that's a high quality because it's going to work faster and it's going to work better, as simple as that. And just sending rubbish out to farms is not the answer, because all you do then is you degrade the whole concept of using compost. High quality compost to us when it arrives, when we have a good look at it, it's got to be almost like soil. It's got to have that real nice loamy texture to it. So it's been processed fully, there's no macro pieces left in it. It's really nice. It smells sweet. Then you've got a good compost to work with.

If the compost supplier supplies a poor quality product into an area, he'll never supply anymore, because the word spreads. And I'm talking compost that's got either glass contaminant, which is an absolute no-no. If you go out to the paddock after you've applied it and it's sparkling, you know there's glass in it. If it's full of twigs and big pieces that are going to take forever to break down, you don't want that. If it turns up and it's got bits of plastic and it smells a bit sour, it hasn't had long enough, it hasn't been done well enough, we wouldn't accept it.

Craig Allen: So there we can understand what end users of compost need, and the critical role we can all play in building healthy soils. Avoiding contamination stops FOGO recycling from just creating more waste. Now, let's return to Western Australia. Greg from C-Wise shares his insights on the benefits of compost, his feedstocks and moisture levels, and the process of creating a product that is clean, consistent, and nutrient rich.

Greg Watts: The best thing about some of our feedstocks is if I look at waste grain, for instance, that we bring in, it actually creates that circular economy story. You're taking grain or cereal waste, you're composting it and returning it back to a farmer who's then going to grow the next crop of oats or wheat. So that circular economy piece is really important. Not only to us now, but also our customers are going, "That's a really good thing to do."

A lot of the food that we eat in the cities, Perth, Sydney, doesn't matter where you live in Australia, but most of that food is derived somewhere out in what I'd call the West Australian wheat belt. The flour for our bread comes from there. Lots of our food products come from the wheat belt. And they land into a city processing environment, and the most important thing we can do there is to actually turn those nutrients that have come from the wheat belt around, turn the carbon that's come from the wheat belt around and send it back to the wheat belt where it's needed to grow the next round. Put the carbon back to the start of the cycle and let's go again with it.

Craig Allen: Well, now it's time to go on the compost journey. Greg talks us through it.

Greg Watts: We're licenced to produce 90,000 tonnes per annum, and we get pretty close to that most years. As I go through our composting stages, the first part of composting is blending of our dry ingredients. We then very carefully bring the pile of dry ingredients up to our required moisture level, which is somewhere above 50 to 55% moisture. From there, we have a short duration of what we call pre-heating, that's where the bugs really start to work and start generating some heat. And once we see some good heat in the pile, so say 40 or 50 degrees, we then move it onto stage one. Stage one is very early, very immature. Stage two is starting to process. Stage three, you're now composted for six weeks. And at stage four, after eight weeks of composting, we're ready to turn that pile over into a maturation pile.

And we like the maturation pile to create... I guess the best term is we want the compost to rest. It's been in process for eight weeks, it's been turned, the fungi have been disturbed. The other bugs in there have been disturbed and rolled and shifted. And then we just like the compost to rest and mature a little bit further before we go through our last stage, which is a screening stage, which is where we do the particle size separation. Where we make the difference between what would be a mulch and a soil conditioner, which for C-Wise is about 16 millimetres. If it's smaller than 16 millimetres, it becomes a soil conditioner. Some of our ingredients are termed high-risk ingredients. We need to pasteurise, which is 15 days above 55 degrees Celsius. And pasteurisation causes the destruction of all the weed seeds, and potential pathogens through heat.

The reason we then roll that onto stage two, is we effectively put the outside on the inside, and the inside on the outside. All that material gets exposed to the higher temperatures above 55 degrees in the middle of the composting pile. We start to see the carbon transformed from what was dry, sharp, non-wetting sort material, like sawdust or something like that. And it actually starts to become a bit softer, a bit more like a sponge. And we do that for another two stages after that. We like to produce really mature composts. The closer I can get my finished product to... And I say this tongue-in-cheek for all your listeners. The closer I can get the product to humus before we put into the ground, the higher it will perform. When I talk to people about our humicarb, that's a maturity level three. It's also organically certified compost.

But while that's the best product that C-Wise makes, not everyone has the budget for that product. We've worked on several trials where we take an immature compost, so maybe maturity level two, and we blend it at different ratios with a maturity level three. And what we see in our trials and performance of the plants, or the crop, which is most important. There's some really interesting work there. We've also done some trials with some semi-mature or immature composts, particularly in a turf application. And what we see there is that the more readily available nitrogen in a semi mature compost, it suits a high performance turf environment. Because the grass, particularly Western Australia where we don't really get a winter, it never shuts down. So that little bit of freely available nitrogen just gives it a little tickle along. And we've proven anecdotally that the initial burst of readily available nitrogen actually deters some of the nasty bugs in our soil, like sting nematode and stuff like that. And it actually drives them away from the root zone so they don't cause damage to the turf.

Craig Allen: Now we have some luscious rich compost, but how does this translate to on-farm success? Greg's team have conducted farm trials over years and found that even low application rates of compost can match synthetic fertiliser yields. He tells us the story about one of his customers who has adopted compost for his 3,500 hectares of crops. We find out what's happened.

Greg Watts: One of our biggest customers has just, for the second year in a row, given us his entire nutrition programme using our compost. So he uses very, very little synthetic fertiliser, which is just a little bit of phosphorus at seeding time to help the germination. After that, it's all powered by compost. And that's one of the most successful farmers in Western Australia. He said, "Greg, I'm fortunate that I can afford to take this risk." And he said, "And the reason I do that is because from the day that we were introduced, C-Wise has worked hand in glove with me around my farm."

We've gone out with him and we've done soil tests. We've looked at what his soil is. We then looked at the crops he wants to grow, and we've worked with him around his nutrition programme and also his soil amelioration programme. He's on typically sandy duplex soils in Western Australia, very low carbon levels, and he wants to build that carbon up but continue to grow good crops. And when you have these relationships with farmers, you absolutely have to respect that. I want to actively, positively contribute to their farm, and not give them just another job to do so I can sell them some compost. So we have to actually work out how we integrate our requirements for compost sales into their requirements for farming.

We've learnt a lot along the way. We've learnt that application is a pain point for them. If you think that all of their machinery is designed around one pass, so the sprayer might be in front of the air seeder, and they drive around the paddock and they seed and that's it. So to spread loose compost, we have to add another task in front of them. What we worked out, okay, if application is a pain, how do we solve that problem for them? We went out and we bought a couple of really large spreaders so their customers can put large volumes of compost out very quickly.

They were really concerned about the crop not getting the nutrition that it needs. So we go open book with them and we say, "This is what your crop requires. You've told us this is what your crop requires, this is what your soil is going to give it. This is how much we need to add." And we actually show them in relation to world fertiliser prices and world raw material prices like gypsum, which provides sulphur, and lime that corrects the pH. And we put a dollar value attached to each of those trace elements and what the compost is bringing around that. So it gives them absolute surety that what they're doing is not going to cost them anymore than using synthetic fertiliser.

Once we've given them that assurance, then we start talking to them about increase in moisture holding capacity, increase in nutrient usage efficiency. When we increase the nutrient usage, you can reduce the amount of fertiliser that they have to supplement with, and that saves them real dollars.

Craig Allen: We finish on Lachlan Jefferies, who has a final word of encouragement for all of us who want to play our part.

Lachlan Jefferies: In the big climate picture a lot of us feel helpless. What can I do? And I think the decisions we make at home and as we walk up to our bin are things that we can do. I think the vast majority of the community are real committed and love that they can play that role.

Craig Allen: Compost manufacturers put a lot of effort into making compost that's clean and safe to use, and they can't do it without our help. If you're interested in finding out more about compost, how to use it, where to get it, or how to make it, then listen to the other episodes in this podcast series where we learn more. Join us next time as we get tips and advice from compost experts, and hear about how compost is transforming farms right across Australia.

Thanks for tuning into the Healthy Soils Podcast. If you're curious about integrating compost into your operation, start small, trial different application rates, and ask your supplier about quality standards. Together we can grow healthier soils, higher yields, and stronger farms. Be sure to subscribe or follow our show so you don't miss out on future episodes where we get down and dirty into compost and how it is changing our soils for the better. You can find more information about what we discussed in the show notes. We can go to the website to find out more. I've been Craig Allen, see you next time.