Compost, our superhero: Part One

• 6 Jul 2020
• Kaicycle
• <figure class=" sqs-block-image-figure intrinsic " > At Kaicycle, we are mad keen on compost. We celebrate International Compost Awareness Week, and sigh with delight as we rake our fingers through a pile of fluffy vermicompost (i.e. worm poop—some of the best fertiliser known to humans). Not so typical of your average Wellingtonian, but we are working on getting more urbanites to celebrate compost with us! Why, you might ask? Compost is amazing stuff with incredible superpowers, but is chronically underappreciated. Compost is the foundation of sustainable food growing, healthy soil and thus a healthy ecosystem. It’s the missing link in our broken, degenerative industrial food system. With good compost, we can grow our food in a way that’s better for us, and the environment, and even help combat climate change. These are big statements, and we will explore them in this blog series. This first blog post is a long one in two parts, giving a compost-centric overview of our food system—“The Problem” and “The Solution”. To talk about food, we need to start with soil. Good food-growing soil is dark brown, crumbly, moist, rich, and smells faintly sweet — not too dissimilar from a good brownie. But unlike your brownie (hopefully), it’s also full of life, from microscopic fungi, bacteria and protozoa to larger critters like worms and insects. To put it in fractions, this nice brownie-like soil is roughly 45% mineral matter (broken-down rock), 25% water, 25% air, and 5–10% organic matter. “Organic” here means anything that is or was once alive — the aforementioned critters, broken down leaves and wood, etc. All organic matter is made up of carbon-based molecules, which come in an astonishing variety of arrangements and flavours. Soil is a lot more complex than mere fractions can suggest. It is a dynamic living system, with countless biological and chemical transactions happening constantly, mediated by a thriving ecosystem of organisms working together. We call this biological machine the soil food web, which works tirelessly to break down nutrients from the mineral part of the soil and dead organic matter on the soil surface, and transform them into food for plants. In return, plants send sugars and other things down through their roots and into the soil to feed these organisms and keep the machine humming. Plants build these nutrients into their biomass, and eventually the plant will be eaten by an animal higher up the food chain, transforming these nutrients again; or the plant will die, and the nutrients will be returned to the soil by “nature’s recyclers” in the soil food web. Our planet has a finite amount of nutrients, so for life to keep going, these nutrients must be constantly transformed, built up, broken down, and built up again. Organic nutrients are endlessly being cycled through the ecosystem, always being used or transformed by a living thing. There is no such thing as “waste” in nature; “waste” and “rubbish” are human concepts, and pretty recently invented ones at that. Composting is simply emulating nature’s natural recycling process of breaking down organic nutrients into a form that can be used again by plants, but on a larger scale, with humans helping the process along. Composting is truly a craft — there are many ways to do it, and some methods are better for soil health than others, but that’s a topic to dive into another day. Adding good compost to soil brings in the living biology and organic matter that soil needs to support healthy, sustained crop growth. This organic matter part of soil, including a happy soil food web, is what cycles and retains nutrients and water, providing crops with exactly what they need, when they need it. With the industrialisation of agriculture and urbanisation, these natural nutrient cycles were disrupted. We turned away from compost in favour of cheap, convenient synthetic fertilisers to replace natural soil-building practices. But the use of synthetic fertilisers damages the finely-tuned biological machine that is healthy soil. So do other common agricultural practices, like disturbing the soil by ploughing and leaving it fallow, and dousing it with herbicides, pesticides and fungicides. All these human interventions injure the soil food web, and over time can destroy it entirely, turning that brownie-like soil into dusty dirt. Without the soil food web in action, crops can’t access nutrients from the soil. Instead of giving the soil our attention and some much-needed rehab, we tend to turn to using more fertiliser to get our crops to grow, and more pesticides to combat the diseases that inevitably come with the poor diet of sickly soil and synthetic fertiliser. The soil food web starts to shut down. Delicate fungi are among the quickest to die off, and with less fungi around, conditions are better for weeds to thrive. So then we add herbicides to the mix… Eventually the soil food web stops functioning altogether, and the organic matter in the soil simply blows or washes away. Without soil’s natural life-support system working, crops need to be constantly dosed with huge amounts of fertiliser and water to survive and grow. It’s like being in intensive care hooked up to an IV — but it’s the norm of industrial agriculture, on large farms in NZ and around the world. The impact of this is that we are losing soil at huge rates, with good growing land gradually turning into desert, soil carbon being released into the atmosphere, and waterways being polluted with chemical and nutrient runoff, even creating huge dead zones in our oceans. The onflow effects on the wider biosphere, including our own wellbeing, are enormous. It puts our ability to feed ourselves in the future in jeopardy — without soil, we won’t have food. Hydroponic lettuce, lab-grown meat and cricket flour can’t feed eight billion people (and even if they could, I wouldn’t be so stoked with that meal). Meanwhile, the fertiliser industry keeps raking it in. It’s pretty bleak, but it certainly hasn’t always been like this, and we can change our food system for the better. It needs to stop acting like a line, and start being a circle. Industrial agriculture is a linear (“take-make-use-dispose”) system: food is grown in one place, transported to other places for processing and packaging, transported again into cities for sale and consumption, and eventually ending its journey as “waste”. It’s also totally dependent on fossil fuels, creating emissions each step of the journey. I heard industrial agriculture defined recently as “the use of land to convert oil into food”. It’s extractive, and doesn’t replenish the land it takes from. The amount of food wasted by this system is staggering—food that wasn’t deemed pretty enough for the supermarket shelf, wasted as it wasn’t sold in time, or sat at the back of the fridge for too long. It might be surprising, but in our homes is where a huge part of this food wastage happens. These wasted food nutrients are more often than not sent to landfill, where they are contaminated and locked up, so can’t be naturally recycled back into the soil. Instead they gradually turn into methane, which has a pretty staggering emissions price tag as well. Industrial agriculture has enabled huge amounts of food to be produced and sold cheaply, feeding billions — but at an astronomical cost to the health of our soil, waterways, biodiversity, our own health, and driving climate change. With a growing world population, we have ever more mouths to feed, but it is a common misconception that we depend on the industrial model of agriculture to feed the world. Following this line will eventually lead us off a cliff. So, it’s time to evolve this line into a circle, and get ourselves a food system that builds soil instead of degrading it. Looking after our soils is our insurance policy for future dinners. With a circular food system, soil resources will be replenished, “waste” will be designed out, and our food-producing days will no longer be numbered. With a just food system, everybody will have access to good food, and it won’t be at the cost of the environment and countless other species we coexist with. And the good news is that this is completely achievable. The first step is to bring the end of the line, food “waste”, back to the beginning of the food-growing story, to form a circle. How do we glue the ends together? Watch this space for Part Two, in which our superhero, compost, enters the stage… (P.S. If you didn’t already watch the soil food web video linked above, you absolutely should! Here it is again…) Want to go deeper into all this good soil stuff? Check out this brilliant masterclass from Aotearoa’s own Regenerate Now. Author: Kate Walmsley, one of the compost nerds at Kaicycle