In nature the soil is, in general, covered with layers of both living and decaying materials, predominantly plants, which we refer to as mulch. The fallen leaves, the animal faeces, the downed trees and other dying plants, the decaying carcass, the stands of grass and herbs and legumes, etc. All these layers of organic materials keep the soil covered and protected from excessive erosion, they retain moisture in the soil by reducing evaporation, as well as insulating the soil from extreme temperatures. They provide food for the soil life, which is the foundation of all life on earth, and eventually they break down and form a part of the soil itself, enriching and improving the soil as organic matter or humus.
Where there is no such cover over the soil, there you have desert. Without a blanket of organic matter to protect and rejuvenate it, without a community of living plants feeding the soil life with their roots and leaving behind their bodies as mulch to armour the soil, eventually there will be no soil. All that will be left will be just sand, and clay, and silt and all the inorganic components of soil. But there will be no soil ecosystem, no bacteria or fungi or worms or beetles or any of the other lifeforms that make up the incredible community of organisms that make our lives and all other lives possible, but which we degrade and destroy and refer to as dirt.
We have seen it so many times in history. A civilisation has cut down their forests, overgrazed their grasslands and ploughed up their soil. Not all civilisations do it but the ones that do, they tend to make a lot of noise for a short period of time and then eventually we just stop hearing about them. At least until enough time has passed that the unfettered unfolding of nature has rejuvenated the soil and repopulated the earth – we call these periods dark ages! Rarely does a civilisation last for more than a thousand years, at least one that has not figured out how to build soil instead of depleting it.
And today we are depleting and degrading soil faster than ever. The estimates I’ve heard range between a third and a half of all the world’s topsoil lost since the industrial revolution. This genocide of the earth, which we dignify with the name soil erosion, is an integral part of a civilisational crisis deeper even than climate change, which we refer to clumsily as biodiversity loss. For the soil is the foundation of all life on earth, the bridge between the death of an organism and the lives of infinite others, and the loss of soil biodiversity is a keystone in the more general loss of biodiversity.
Once again, the blandness of the language obscures the severity of the problem. You see, all life depends on all other life, that is one of the many lessons of ecology. The greater the diversity of organisms in an ecosystem then the healthier the ecosystem and the more hospitable it is for the many lifeforms that make it up. So, what happens when the diversity of life in every ecosystem on earth collapses all at once in a short space of time? Well, we’re about to find out.
I mean, there have been mass extinction events in the past. Maybe not any caused by a single species before, but that’s not really the point. Nature survived and eventually recovered, and the world was repopulated with entirely new kinds of organisms, descendants of the few adaptable beings that had managed to survive the cataclysm. Maybe that’s the endgame. The selfish gene writ large – exterminating all the competition so that everything on earth can be descended from you. Somehow, I don’t think so. That’s just not how evolution works. Silly strategies like that are just dead ends leading to extinction. After all, the apex predators are generally among the first to fall, and we have tried to position ourselves at the apex of every ecosystem everywhere.
The crises of climate and biodiversity are intertwined and, as usual, the keystone is the soil. It’s a shame that you don’t hear the climate crisis too often framed as a matter of the disruption of the carbon cycle. Because this framing can really help clarify the issues involved. For the way the carbon cycle works, at least on land, is that carbon is continuously being transferred from the atmosphere to the soil, beginning with the magic of photosynthesis and ending up in the soil through root exudation and eventually through the natural process of dying and decaying that covers the earth in mulch. Now, the carbon cycle is more complex than that and it’s not a straight downward transfer, there are flows going all about in all directions, but it is a colossal net flow of carbon from the atmosphere to the soil. So much so that when plants first colonised the land the concentrations of carbon dioxide in the atmosphere plummeted. It happened again when the first flowering plants developed. It’s even speculated that a massive bloom of freshwater azolla ferns in the Arctic ocean, after sinking to the bottom of the sea and taking all their carbon with them, caused the Late Cenozoic Ice Age.
Today we are the anti-azolla. We have disrupted the balance of the carbon cycle, much like the azolla blooms did 49 million years ago but now in the opposite direction, by releasing all the accumulated carbon of billions of years of living and dying from the soil and belching it into the atmosphere. And not only through the burning of fossil fuels - approximately a third our entire legacy load of carbon emissions came from the oxidation of soil organic carbon, which followed the destruction and disintegration of the soil, primarily through deforestation and tillage. So, we know that at least a third of all the excess carbon that we have released into the atmosphere can be drawn down and stored back in the soil, where it belongs. And probably far more than that I would expect.
Isn’t that just the biggest no brainer you could possibly imagine? To draw down as much excess carbon as we can out of the atmosphere and to store it safely in the ground in the form of fertile topsoil. After all, carbon is the building block of life, at least as we know it, so all this excess carbon dioxide in the atmosphere can be seen as the solution as much as it is the problem. For what is carbon dioxide but carbon and oxygen, the two essential components of photosynthesis and respiration, the two basic processes of life on earth. So basically, there’s too much carbon dioxide in the atmosphere, but at the same time there’s not enough diversity of life on earth and there’s too little organic matter in the soil. The solution is so obvious, it almost seems too good to be true. But it isn’t, though we are running out of time.
The solution is literally just to allow the carbon cycle, and all the other nutrient cycles, to work the way they are supposed to. Plants draw carbon down out of the atmosphere and once this carbon has been cycled through an endless diversity of different lifeforms, both above and below ground, it ends up mostly stored in the soil in the form of stable humates. This is just how life, at least life on land, works. But we can accelerate the process. Not only will it help to dampen down the impact of the climate crisis by drawing down massive amounts of carbon from the atmosphere, but it will also form a foundation on which the great and necessary process of building back biodiversity can begin.
Build back biodiversity. That must be our watchword. And building back soil biodiversity is the best place to start. For the activities of the many organisms that make up the soil ecosystem, which we sterilise with the term ecosystem services, form the foundations on which all other beings stand, including ourselves. We are a part of nature - its laws govern our lives far more effectively than our pitiful excuse for laws and governments. But we have strayed from the path on which our lives depend. We have stripped the earth bare, ploughed up the soil and replanted it in monoculture. But we have forgotten that no life can long exist without any other life. And now our landscapes, simplified beyond all possibility of regeneration, are dying. Soon they will take us with them. The earth will recover sure, but how much poorer will it be without all the species we take down with us, without even ourselves.
So, with all this in mind, I submit to you that the absolute best thing we could do right now is to cover the whole earth with a nice thick blanket of mulch. Instead of being blanketed with a nice cool layer of organic matter, today the earth is covered with another type of blanket, a blanket of excess greenhouse gases, holding in the heat and heralding the apocalypse. We have already replaced the blanket of mulch which protects the earth with a blanket of greenhouse gas that scorches it. If we can do that, then surely, we can do it again in reverse.
So, what can you do to contribute to the great re-mulching of the earth? Well, if you have a garden you could start by leaving your grass clippings down where they fall, or else putting them in your compost, as well as by cutting less frequently so the grass is able to produce more biomass and support more biodiversity. You can leave the leaves that fall from the trees down on the ground where they land, or at least turn them into leaf mould and spread them back out. And you can compost your food waste and your paper waste and your own waste and then spread all the lovely black gold you produce around your veg and your flowers. You can plant deciduous trees and shrubs and herbaceous perennials and spread your prunings and your choppings out as mulch. You can chop and drop your annuals onto the ground at the end of the season instead of removing them, or else simply leave them to die back naturally. And instead of digging your veg and flower beds you can just gather up a load of mulch, spread it out and let the worms do the digging for you, like nature intended.
But the real change needs to happen in agriculture. That’s where all the land is. And for that we need political solutions. For the farmers know, for the most part, what needs to be done, and they want to do it, for no farmer wants to leave the land to their children in a worse condition than they found it. But the farmers are trapped. Deep in debt, stuck on the cycle of input dependence and squeezed every which way they look, farmers can scarcely afford to keep the farm going, let alone invest in the land. So, farmers must be supported if they are to adopt practices such as cover cropping, living mulches, min / no-till, holistic planned grazing, continuous cover forestry, agroforestry etc., which are needed if we are to cover the earth in a blanket of mulch. And the power of the supermarkets and the meat packers and the agrochemical giants needs to be challenged so that farmers can be paid a fair price for their produce, without having to overpay for their costs of production, leaving them financially secure and able to invest in their land. And the farmers should be rewarded for doing what needs to be done. The more carbon they sequester and store in the soil, the more biodiversity on their farm, the more subsidies they should be paid. For farmers, as well as producing the food that we eat, also take care of the earth that we depend on, and for this they should be paid a fair wage. And this is only for starters.
Radical changes are required if we are to avert catastrophe, changes in the way we see the world, the way we relate to each other and the way we relate to ourselves. More than anything else, we are facing a crisis of the imagination. The mowed grass, the clearcut forest, the bare field, the monoculture of grain, these are the landscapes of our minds – simplified, sanitised, empty and hollow. But the world you imagine is also the world you create and if we keep on believing we are separate from nature then, by driving ourselves to extinction, we just might make it so. In the hungry times of the second world war the motto was dig for victory. Today, the soil has been dug up and left bare, defeated and hungry, and all that is left to us is to mulch for survival.