Spotted Pigs and Green Tomatoes (14 page)

Lady Eve was entranced and she set up the association and published her book,
The Living Soil,
which encapsulated her belief that that the health of soil, plant, animal and man is one and indivisible. 'The criteria for
a sustainable agriculture,' she wrote, 'can be summed up in one word - permanence, which means adopting techniques that maintain
soil fertility indefinitely; that utilise, as far as possible, only renewable resources; that do not grossly pollute the environment;
and that foster life energy (or if preferred biological activity) within the soil and throughout the cycles of all the involved
food-chains.'

Monty Don once told me that he had a dream when he was a young boy in which he'd been planting some seeds and his hands were
buried in the soil, but it wasn't the seeds that began to grow. It was his hands, stretching down into the earth and turning
into roots. When he woke up, he knew he wanted to be a gardener. But to most people, and indeed to me until recently, soil
is just pretty boring stuff which clogs up the bottom of your wellingtons: it is indeed the dirt beneath our feet. Governments
have spent a fortune exploring the potential for life on other planets, but exploring the soil is a fledgling, under-funded
and unglamorous industry. Yet the earth in our gardens, our fields, our forests, as well as the sediments at the bottom of
every river and stream and marsh, harbour the most diverse life known in our universe. It is nothing short of magical. It
is also critical to our survival. Without it, we literally have nothing and would be nothing. Every bit of energy that the
world has comes from the sun, and there is only one way that living creatures can obtain it. Only plants can convert the power
of the sun into the sustenance that all life on earth needs and it is the soil, in all its marvellous complexity, that allows
this intricate exchange of sunlight into digestible energy to take place. Leaves and roots, forged in the reaction between
the sun and the soil, have enabled us to create our civilisations and to look outside ourselves towards the distant surfaces
of the planets.

Inside every leaf the chloroplast cells are tiny workshops for photosynthesis, the process which traps the sun's energy and
converts it into carbohydrates. To do this the plant takes in carbon dioxide from the air and emits oxygen: the exact reverse
of the way animals breathe. Using the sunlight for energy, it strips away the carbon and uses it to assemble sugars and other
organic compounds needed to fuel life. In the process, the microbes discard the oxygen molecules from the carbon dioxide,
creating the most precious waste in the universe. But the plants don't just need sunlight and C02. They need water and they
need minerals. Both these come from the soil. Soil has been called 'the poor man's rainforest' because a single spadeful of
rich garden soil may contain more species than the entire Amazon rainforest nurtures above ground. Think about it: it is,
to coin an overused word, awesome. Two-thirds of the world's biological diversity lives in the soil and in underwater sediments.
You could call it a micro-menagerie and it includes uncatalogued millions of microbes, mainly bacteria and fungi, single-celled
protozoa, and tiny animals such as nematodes, copepods, springtails, mites, beetles, snails, shrimp, termites, pillbugs and
earthworms. Crumbling the rich, dark soil through my fingers, I try to get my head round the fact that this neglected substance
is actually stuffed full of tiny creatures all performing an essential part of life's essential rhythms. It's the sort of
idea that, in 1960s hippy speak, blows your mind away.

The Harvard University ecologist Edward O. Wilson calculated that 93 percent of the 'dry weight of animal tissue' in a patch
of Amazon rainforest belongs to the invertebrates, from mites and springtails to ants and termites. And that, apparently,
doesn't count the microbes. Despite their minute size, the bacteria in an acre of soil can outweigh a cow or two grazing above
them. Most of the underground creatures live near the surface but there are some extraordinary beings known as 'extremeophiles',
bacteria and ancient microbes, which live a mile or more deep in the earth, or in boiling springs or polar ice. Although most
soil organisms are tiny and short-lived, some are huge and very, very old. American soil scientists have measured the Armillaria
root-rot fungus, a sprawling underground mass which can exceed the size of a blue whale. The largest yet discovered stretches
under 2,200 acres of Oregon.

Wilson calls the creatures below our feet 'the little things that run the world'. Soil science is in its infancy, but what
we do know is that, acting together, these little things form the foundation for all life on earth. They break down organic
matter, store and recycle nutrients vital to plant growth, generate soil, renew soil fertility, filter and purify water, detoxify
pollutants, control plant pests, yield up our most important antibiotics, provide us with vitamins and minerals, and help
determine the state of the earth's atmosphere by their absorption of greenhouse gases.

In prehistoric times, long before we started mucking around with it, our soils were so rich in vitamins and minerals and goodness
that trees could grow ten metres in a single year, and in the late Jurassic period, the gigantic thunder lizard was the size
of a swimming pool and weighed twenty-five tonnes. Yet it was a vegetarian with a mouth the size of a horse. To grow that
big on a purely vegetarian diet, nutritionists estimate that the plant life must have contained thirty times the mineral levels
that we find today.

Of all the creatures that live in the soil, the nematode is the most extraordinary. It is the most diverse and abundant creature
on the planet; four out of every five animals are nematodes and in a single square yard of pasture soil you could expect to
find ten million of these tiny worm-like creatures. Throughout the world, 25,000 species of nematode have been named, but
there are several million more waiting to be identified. Not all nematodes are benign microbe-eating decomposers: they can
also be hookworms, round worms, ring worms and the cause of elephantiasis and river blindness.

Nematodes are so structurally different from us that, in biological classification terms, they are grouped under their own
phylum. The phylum that we belong to, called the chordate phylum, also includes all birds, reptiles, amphibians and fish,
as well as mammals. Nematodes breathe and reproduce in a unique way: they are characterised by their S-shaped, snaky movements.
Some are free-living, some are symbiotic, others are parasitic, but they all playa vital role in the process of breaking down
dead and waste matter - plant and animal­and in making it ready for re-absorption by a new plant.

Each earth creature eats waste and excretes it, in the process making everything smaller and smaller. They then mix the organic
matter with the minerals in the soil and with fungi and bacteria. They move the dead matter downwards where it gets eaten
again by different types of bacteria. Bacteria come in all shapes and sizes: some secrete a sugary gum which binds soil particles
together; others break down molecules so that they can be absorbed by the plant roots. The cyanobacteria, single­celled organisms
in a kingdom of their own, turn the nitrogen in the air into soluble nitrogen which plants can take up through the soil. Other
bacteria change molecules into amino acids which plants translate into vitamin C.

Fungi secrete specific enzymes that chop up molecules into the exact sizes and shapes that plants need. Tiny protozoa roam
the soil and feed on the bacteria and fungi. In the process of feeding they release excess nitrogen which the plants take
up through their roots. Various organisms, including fungi, help plants take up the minerals they need as well as acting as
physical barriers around the roots to stop disease. Others attach themselves to roots, operating like vaccinations which trigger
an immune response in the plant. Other organisms directly attack harmful bugs. It's a complete, complex, totally interdependent
world which provides the basis for plants to grow, and to harness and pass on the energy of the sun. Every plant has its own
diet and knows what to pick out of the vast quantity of minerals, acids, carbohydrates, hydrogen molecules to enable it to
perform its genetic inheritance. So a carrot will select what it needs to produce vitamin C, beta carotene and other vitamins.
Flowers will take something different. Trees something different again. When the cow comes to graze, it will choose to eat
the plant - grass - that tastes good but also enables it to grow and produce beef.

Standing in the potting shed, with my hands buried deep in the mound of rich potting soil, it's weird to imagine all this
going on inside this pile of earth. One thing is clear though: somehow or other this rich array of species manages to coexist
successfully. It has long puzzled scientists how this is possible and they attribute this peaceful sustainability in part
to the tremendous diversity of habitats available, from tiny soil pores to clumps of soil particles to larger patches created
by the engineering work of ants or earthworms. Food sources like plant litter, root secretions, dung and dead bodies are patchily
distributed throughout the soil. Above ground, competition for resources has limited the number of species that can pack themselves
on to the planet: down below, competition is less fierce, possibly because the little creatures cannot move well and because
many spend long periods in dormant states. But thinking about the world beneath as like our own with tiny animals bustling
along, jostling for space like crowds of shoppers on a Hong Kong street, is inaccurate. From the point of view of the microscopic
organs, there is plenty of space and plenty to eat. The typical soil microbe, according to George Kowalchuk at the Netherlands
Institute of Ecology, plays a long game: 'They can wait a really long time, perhaps years. Then when a root comes along or
a drop of water or whatever, the cell blooms into a colony. Once the plant or the source of riches is gone, the colony dies
out and the few remaining microbes go back to waiting.'

At the beginning of the 1990's, I used to playa computer game called SimCity which became incredibly popular amongst journalists,
so popular that at the
Daily Telegraph
it was banned as being an addictive time-waster. The principle of SimCity is brilliant: the player is presented with the outlines
of a city and a sum of money. As the newly appointed boss of the city you decide how to spend your cash. You can build roads,
or hospitals, or art galleries, or parks, or low-cost housing, or yuppie apartments. You can buy buses, or statues, or install
a metro. Or you can make provision for people's pensions, or pay council workers higher salaries. The game is endless in its
permutations and my daughter Daisy, who was then ten years old, became addicted too. What is abundantly clear from SimCity
is how even apparently random acts have knock­on effects: that everything is indeed linked up to everything else. If you build
too many parks, there's not enough left for buses to get people to the parks. Too much yuppie housing means that hospital
workers have nowhere to live.

It was in the middle of our SimCity craze that Daisy and I went on our first safari, to the Okavanga Swamps in Botswana. At
dawn on our first morning, we awoke to the sound of an elephant crashing around outside our tent. We were both too excited
to breathe.

One of our guides was an insect specialist who took us on bush walks. After he let us marvel at the magnificence of a termite
mound, he instructed us to just stand still, put our heads down and study the ground. After days of watching big, grand animals,
it took a few minutes to adjust and get used to looking at the tiny insects. There were hundreds of them, moving this way
and that, rustling through the grass, intent on their business. He told us that all of African life depends on these tiny
creatures, and that the removal of one species would drastically affect all the others, and that the removal of these termites
would result in a dead, useless land where nothing could hope for life. Daisy looked at me and said 'Mum, it's nature's SimCity.'

We were seeing the real interdependence of the natural world but, apart from humans, it is only the insects who have established
anything remotely resembling cities. What sets humankind apart from other creatures is our ability to grow food, and our ability
to live in large groups which in turn can support great institutions. Cities are the heart of our global world and they need
to be subsidised from the outside. That makes them vulnerable. A small town won't possess a museum or a specialist neuro-surgeon,
but its inhabitants live closer to sources of food. As cities get bigger so the brilliance of our civilisation becomes increasingly
evident: opera houses, metro systems, grand monuments and stately buildings. But as they get bigger they become increasingly
dependent on supply chains, electricity grids, water and food that is produced far away. We inhabit our concrete streets and
take for granted how it all works but, like the planet we live on, cities walk a tightrope to survive.