CSI but not as we know it; how Katia Taylor’s taking on a Carbon (in) Soils Investigation
Katia Taylor’s always been a fan of detective stories. Now, through her work at CSIRO, she’s investigating the mysterious case of disappearing soil carbon.
Katia Taylor, 28, was a 2024 evokeAG. Future Young Leader, and Postdoctoral Researcher at CSIRO. With a focus on enhancing cropping system resilience and sustainability, Katia’s work involves harnessing microbial communities to enhance formation of soil carbon from crop residues.
Across every one of Earth’s continents, were seeing disturbing declines in soil health. Perhaps most concerning is that over the past 200 years, we’ve lost up to 60% of soil carbon from our agricultural soils.
Along with nutrients, carbon is an important part of healthy soils, and takes hundreds of years to build up as plants, animals and microorganisms slowly decompose.
Carbon rich soils hold on to water better, they’re less easily eroded, and they’re more resilient to extreme weather. There’s no quick fix that can restore the health of our soils once they’re gone.
But what’s causing these declines in soil carbon? And how can we stop it from disappearing?
A detective not afraid to get down and dirty
Let me set the scene first because every mysterious disappearance needs a detective to solve the case – me.
I was a very inquisitive and outgoing kid, I loved nature and animals, and I wasn’t afraid of getting my hands into the organic matter.
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I eventually figured out that if I pursued a career in science, I could basically be a detective in helping find solutions to environmental issues.
After doing a PhD in plant science, I joined a team at CSIRO that work on developing farming system approaches to improving food production. My research is focused on the microbiome that degrades crop residues.
A microbiome is a community of microorganisms, like bacteria and fungi, that live and interact with one another in a specific place. In this case, soil and crop residues.
Katia Taylor, evokeAG. 2024 Future Young Leader. Image | Rachael Lenehan Photography.
Can suspect number one please stand up
Who is our first suspect in this detective story? Well, that would be the humble plough.
Over the past 20 years, our cropping systems have been revolutionised by the adoption of conservation agriculture practices, including minimum tillage, crop residue retention, and crop rotation.
Minimum tillage – where the soil is left largely unploughed – has delivered enormous benefits when it comes to soil moisture retention and prevention of soil erosion. There has also been an expectation that no till practices will help prevent loss of soil carbon.
But research looking at the impact of tillage on soil carbon, has shown that despite having other benefits for soil health, no-till practices haven’t always increased soil carbon. Instead, no-till can increase the amount of carbon stored in the surface layers of the soil, but it can also decrease the carbon stored in the deeper layers, leading to a reduction of soil carbon throughout the soil profile.
In the case of missing soil carbon, the plough is our first red herring. It doesn’t fully explain the loss of carbon from our cropping soils.
On to suspect number two
The second pillar of conservation agriculture – and the second suspect in this detective story – is the practice of retaining crop residues to improve soil cover and build soil carbon.
The idea here is if you take all the carbon, that the crop is so beautifully captured from the sun’s energy, and you put it back into the soil, then you can build carbon within the soil.
Katia (far left) with the evokeAG. 2024 Future Young Leader cohort. Image | Rachael Lenehan Photography.
This helps prevent loss of soil moisture, but we now know that in some cases, retaining crop residues does not increase soil carbon. In fact, it can lead to loss of soil carbon.
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Can it be that crop residues are the culprit in this case of missing soil carbon?
Spaghetti without sauce is like crop residues without nutrients
Why is it that when we add crop residues to soils, we can lose soil carbon? This is where the microbiome joins our list of potential suspects.
Feeding carbon rich but nutrient poor crop residues to the soil microbiome is like giving somebody a bowl of spaghetti without any sauce on it.
Think of the spaghetti as representing crop residues and the sauce as representing nutrients.
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Microbes can’t eat the spaghetti without some sauce, but the only other sauce available is locked up with existing soil carbon in the soil.
When we add the carbon rich but nutrient poor crop residues to soils, the microbes mine the existing nutrients and carbon from the soil, releasing carbon dioxide at the same time.
This is why we can actually lose soil carbon and we retain crop residues, rather than build it.
In a lab at CSIRO, a team is working on a solution. This is their story.
What are we going to do about this crop residue microbiome – the apparent culprit – in this case of missing soil carbon.
Fortunately, our team at CSIRO has a solution. If you instead give the microbes everything they need to break down the crop residues; a balanced diet of both spaghetti and sauce, then the microbes can break those crop residues down and build soil carbon without eating into any of the existing nutrients or carbon stored in the soil.
Our team carried out a long-term field trial using this approach and showed that over a five-year period it’s possible to build over nine tonnes of carbon per hectare, which would earn you over $1,000 per hectare in Australian carbon credit units. And that isn’t counting the benefits to the crop of having healthy soil. These findings highlight the need for a paradigm shift towards more strategic deployment of nitrogen fertiliser.
Katia is on a mission to solve this case of disappearing soil carbon. Image | Rachael Lenehan Photography.
Understanding the crop residue microbiome is critical if we’re going to achieve this. I’m using cutting edge sequencing technology to see which microbes in the community are the ones that are actively breaking down the crop residues. I’m also testing out different soil amendment amendments for their ability to increase the efficiency of soil carbon formation and its stability within the soil.
The science I’m sharing is still developing but one thing is certain – no-till practices haven’t been the silver bullet that we’d hoped for when it comes to preventing loss of soil carbon.
If we want to ensure the longevity of our healthy soils then our governments, industries, and our communities need to embrace additional strategies that might be better suited to building soil carbon in certain soils.
Together, let’s follow the clues that are right beneath our feet and solve this case of disappearing soil carbon, once and for all.
Katia Taylor was part of the 2024 Future Young Leaders program that saw five emerging leaders in agrifood, innovation and related industries build their capabilities, skills, confidence and networks, to ultimately present their key message, innovations or research project on an AgriFutures evokeAG. 2024 stage.
Sign up here to hear more from the thought leaders and change makers about the role of agrifood tech innovation in shaping a sustainable future and receive updates on evokeAG. 2025 in Brisbane, Queensland on 18-19 February.