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November 4 - November 8, 2024
Everything is intertwined. It’s easy to forget this when you’re late for the 7.35 a.m. train, heading into the office to meet with a grumpy boss, with a pay packet that barely covers the rent, let alone a posh night on the town.
Legumes such as peas and beans capture nitrogen from the air and hold it in these nodules, which help replenish soil’s fertility. They make the ground better for themselves, and the plants that follow.
There’s abundant evidence from developed nations showing that urban children have more autoimmune diseases than those who are exposed to soil bacteria. Termed the ‘hygiene hypothesis’ in 1989,8 the theory has been that many of our allergic reactions, and the diseases associated with them, are the result of being too far removed from microbes, particularly those from soil.
Population studies have shown that the more soil microbes you’ve been exposed to, the more likely you are to have a stronger immune system.10 Playing with dirt has never been more scientifically accepted.
We’ve evolved around living earth, and our ability to sense geosmin could well explain why it feels so invigorating being in a garden, or so life-affirming to visit an ancient forest, as well as why the smell of summer rain lifts the spirits beyond the mere relief of it watering the garden. Soil microbes make rain smell joyful.
People can do what they like with their diet, but really, globally, the best advice is the most boring. Eat a wide variety of plants, mostly. Eat your veg. Sure, have some meat, some sugary treats, some fast food if you want – but if you eat well 90 per cent of the time, that other 10 per cent isn’t really so important.
The truth is, modern industrial agriculture means we are eating less nutrient-dense food than our grandparents did.
A comparable study from the United Kingdom showed that carrots now have a third of the vitamin C they did in the 1960s, magnesium has dropped nearly in half, and sugars have increased by a third.
In 2009, the American Society of Horticultural Science reported that ‘side-by-side plantings of low- and high-yield cultivars of broccoli and grains found consistently negative correlations between yield and concentrations of minerals and protein’.19 The bigger the heads of broccoli, or the more tonnes of grain per hectare, the lower the nutrient density.
The dilution effect is very real, then.20 And in large part it can be explained by cultivar selection. We’ve chosen higher-yielding plants, not more nutrient-dense plants; more carbohydrate per gram of food produced, less of the other nutrients. Pretty much all plant selection, for food, has been based not on nutrient density, but on yield and looks, and the ability to thrive in a high artificial-fertiliser environment.
The reason most of us don’t eat our veg is because it’s boring. Modern cultivars have been stripped of nutritional value and flavour by a system geared to the grower, not the eater. We’ve focused on quantity not quality.
What actually does work is variety. So a Mediterranean diet that targets a mix of foods, not a single ‘superfood’ or a single villainous component of food, works better on a range of health measures than simply a low-fat diet. Eating as many different, complex-tasting delicious plant foods we can, with a small amount of pasture-raised meat if you’re that way inclined, is what we are constructed to eat and enjoy.
Tilling the soil is a losing game, not only because it upends earth ready for all three types of erosion. It also destroys soil’s microbial home, and soil’s major glue, glomalin, which we met in Chapter 4 and will come back to again.
How do worms do this miracle increase in yields? Humic acids, formed in the gut of worms, act almost like hormones, which enhance plant nutrition and growth. Worm-produced humic acids allow a plant’s roots to grow longer, and put out more branches. New growth from more branches means greater ability to absorb nutrients.
Since about 1985, we’ve been pretty sure that humic acid can release phosphorus from soil and make it bioavailable – that is, available in a form that a plant can take up. And we now know that humic acid from worm guts is also really good at dissolving rock. So, worms don’t just help plants to grow, they actively help make soil structure from rock crystals.
In essence, worms act as the engineers of soil structure. They’re big enough to move matter around, and they move faster than fungi, plant roots and most other subterranean life forces. They can incorporate leaf litter into the soil, and through their actions of forming castes, burrowing, making middens and other activities, earthworms can significantly alter the physical properties of soil, as well as nutrient availability.
In short, they provide for more air in the soil, and better water penetration. They speed up root growth and improve plants’ root structure, all the while moving significant amounts of minerals and organic matter, mixed through the worm’s guts, throughout the structure of the soil.
The problem isn’t with Haber’s ammonia, but more with how it’s made (using extraordinary amounts of fossil fuels), and what it does to the environment. In short, all those beautiful soil bugs that we met in earlier chapters tend to get turned off by nitrogen in artificial fertiliser. A big fat injection of Haber’s nitrogen, if it doesn’t kill the microbes, certainly makes for a lazy subterranean ecosystem. And just like a sugar rush for a human, there’s a post-nitrogen slump. The quickest, easiest way to get over the slump is to add more nitrogen. But it’s a losing game.
Nauru was once a tropical paradise. Before that, it was a toilet. For an estimated 4 million years, prior to human habitation, Nauru was where a lot of seagulls emptied their guts.4 Over millennia, the birds’ poo accumulated, then calcified. After being inhabited by Polynesians and Melanesians for an estimated 3000 years, a European prospector, Albert Fuller Ellis, arrived in 1900. Ellis found what looked like calcified wood on the island, but turned out to be ancient seagull poo – and the richest source of phosphorus ever discovered. A persuasive alliance of three Commonwealth nations,
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fodder. In fact, over half the total grain output of the United States, and over 40 per cent of the global grain production, is fed to livestock.
We’re not using animal waste the way we could be. The use of fossil fuel–based fertilisers doesn’t produce the results that animal poo can. Animals upcycle nutrients, and so their waste can be utilised better in the ideal farming system.
The plough was the single biggest emitter of human-induced carbon into the atmosphere up until about the 1950s.2 Bigger than coal, bigger than oil.
Grow food and you mine soil, some say. By removing the plants, or the animals that have eaten the plants, you remove nutrients. Ploughing not only leaves soil vulnerable to erosion, it also kills the complex ecosystem underground.
We like ploughing because it reduces the weed load, so the planted seeds don’t get outcompeted. We like it because the initial digging gives us that hit of nitrogen for our crops. Ploughing has tamed formerly wild lands and made growing food more manageable, smoothing out bumpy ground.
Often, with your home garden, you’ll still hear people suggest that you dig over the beds between harvests, to ‘aerate’ the soil, to dig compost or other fertiliser into the soil, to cull some weeds. In the short term, this can appear low impact. But in the long term, the damage is profound. It’s a long, slow drip, a leaching of available nutrients, where the soil doesn’t forget, but it can happen too slowly for us to notice in a hurry.
The best way for growers to protect soil is to avoid bare earth – whether it’s in your home garden, or on the world’s biggest farm. Don’t dig if you can help it. Ideally, keep continuous, living plant cover if possible, mulch any bare earth, and encourage diversity. The more diverse array of plants you can grow, the more diverse your soil microbes become, and the more resilient your land is.
Another European mechanism for making soil – one that seems to only be practised now by the hippies and permaculture junkies – is hugelkultur, a German word meaning ‘hill culture’. Anecdotally, this soil-building technique was born of the forestry industry in centuries past. Waste wood from logging is laid around hills, perhaps mimicking terraces, or put into shallow trenches and piled up, then covered with earth.
The best soil, growing the best food, is the soil that has been given the utmost attention – most likely by the person who is going to eat that food. It’s in the home or urban garden, where the effort you put into your soil can not only be felt in your hands and back, but also be tasted on the plate. The best soil is waiting for you, or waiting for you to make it, outside your back door.
Weeds exist because they’re healing soil. They’re colonising your garden, cropland or paddock because there’s a vacancy in the ecosystem for them. They’re there, persistent and resilient, because the conditions in the soil – both its life and its structure – are ideal for the weeds, and not necessarily ideal for what we want to grow. Importantly, in the process, the weeds are feeding subterranean communities, and often fixing the very problems in soil that have allowed them to thrive in the first place.
Often, on our arable land, we try to grow things that want to die, and try to kill things that want to live.
As we’ve seen, bare soil is damaged land. Every time you see bare earth, that is soil dying, whether that’s in the pig paddocks or the market garden. It’s amazing the damage we do to grow vegetables.
Anywhere that we see just one species, we know soil is being starved. Nature doesn’t do it; plants don’t like it.
And it’s not just diversity in plants. On our farm we want more insect varieties, and lots of insects in total, even as we try to manage the pest species in the garden. Ecological harmony above ground equates to ecological complexity and harmony underneath.
What’s the best thing you can do with the little patch of the world that you can control, because you work it with your own hands? What can you do in your garden? Make compost. And perhaps plant charcoal. But most importantly, think of yourself as a grower of soil.
Estimates put it that each calorie of food we eat in places like Australia is the result of 10 calories of burnt fossil fuels used to grow the food1 – releasing carbon not only from the fertiliser and the tractor, but also from the soil.
Caring for soil is a very personal contribution you can make to your well-being. It’s a very tangible act, where what you do affects you mentally, physically, and perhaps even spiritually. It’s intellectually stimulating, you’re exposed to the mood-enhancing capacity of soil microbes, and the end result is food that is better not just for you, but for the world.
There are some general guidelines to remember about how to maintain complexity, like not disturbing your soil. Like covering soil, with living plants or mulch, whenever you can, to protect the ground and help it thrive.
In short, the five principles of regenerative agriculture4 look like this: 1. Keep the soil covered (no bare earth). 2. Minimise soil disturbance (don’t dig). 3. Aim for diversity (in plants and animals). 4. Make sure you have living plants all year round. 5. Integrate livestock.
For many, the thought of Planet B is tantalisingly alluring, when, actually, the best we can do is keep a cotton seed alive for a bit over a week. Meanwhile, back on Earth, we’re busy creating moonscapes.
The only way to heal the world and to live our best lives is to care for the earth that supports us.
Out of 7.8 billion people currently alive, a full 3.7 billion people are malnourished.4 This is despite the fact that we grow enough food for about 11 billion people, at least in macronutrients.
What’s more, of the food we do produce, we waste about 40 per cent5 – thrown out on farms, at food processors or wholesalers, as well as in homes. Some say closer to 50 or 60 per cent is lost to waste.6
The Green Revolution, as we saw, did increase some yields, but most of the gain went into feeding ethanol plants and factory farms, not the poor in the world.
For the last 100-plus years, we’ve reduced soil to the chemical and physical, and added the nutrients we think it needs. It’s time we celebrated the biological, and restored land in quantities that can help slow climate change. We need to consider soil as the massive store of gases, life and nourishment in the holistic sense that it is: soil as an almost incomprehensively complex underground super-organism, capable of sustaining life on Earth. It can feed 10 billion, easily, if we do that.
If science has shown us anything, it’s that mother nature is on our side. We just have to work with her, not battle her constantly.
Adding biochar to soil is rarely going to hurt, either, though many suggest soaking it in compost tea first to inoculate it with microbes.
