Essential Facts about Soil
I was asked to write a short piece about soil for Glastonbury’s Climate and Ecological Emergency’s Advisory Committee’s newsletter. This publication’s editor wanted to devote her next issue to information about the soil, and she seemed to be having trouble getting started on the project. So she asked me to write down some basic facts about soil. In the end she filled up her four skimpy pages whilst using hardly any of what I gave her, preferring a few snippets from our conversation, and from a few other selected people who she talked to. Nevertheless she included most of the information I gave her, even if it was in other people’s words, and she assured me that what I’d written had been very useful. I feel that my collection of ‘essential facts about soil’ are worth knowing, so here they are:
- The Earth’s topsoil has taken millions of years to be created. Besides minerals from rock dust, billions of plants and creatures have died and decayed to form a layer of nutrient-rich humus that is truly a foundational wonder of the world! Without this layer, life as we know it now could never have existed.
- Healthy soil is not an inert substance, it is alive. It contains countless numbers of living organisms, from microbes up to earthworms.
- Industrial agriculture, in particular the use of chemical fertilisers and pesticides, has systematically ruined the integrity of the soil, causing it to erode and wash away. If this continues for another two generations, we shall have no topsoil left on our agricultural land.
- The story that industrial agriculture is essential to feed the modern world is a myth. Small, organic mixed farms could feed the world successfully – making communities more resilient, individual farmers independent from crippling bank-loans, and the soil much better looked after – but they would not make giant profits for giant corporations.
- The know-how and the technology to regenerate the soil exists, mainly through farming practices that use and encourage the breakdown and assimilation of organic matter, together with mycorrhizal (root-like) fungi, and soil bacteria. These ‘regenerative’ practices are not being fostered by governments or agribusiness corporations.
- Industrial agriculture takes 12 calories of fossil fuel, and fossil-fuel-based chemical inputs, to produce 1 calorie of food. No wonder the world is over-heating! (In the 1940s 1 calorie of fuel and chemical inputs produced 2.3 calories of food; by the 1970s it was down to 1:1; now it is completely unsustainable).
- Naturally, soil holds three times as much carbon as the atmosphere, and the biosphere – the plants that grow in the soil – also hold twice as much as the atmosphere. Healthy soil and plant growth draw down carbon from the air, and could contribute more to solving climate change than anything else.
- ‘Mob grazing’ is being taken up by many farmers these days. (It’s been on the Archers!) This mimics herds in the wild; they move quickly across the land and bunch closely together, as the best natural protection against predators. The herd animals trample more vegetation than they eat, but quickly move on and leave the land to recover. This is perhaps the quickest method for increasing organic material in the soil, and the soil’s carbon content.
- Composting increases the humus in the soil and encourages soil microbes and mycorrhizal fungi, helping to provide good soil structure, water retention and plant nutrients. It is used successfully in the back garden, and increasingly in farm-scale operations.
- There are two types of microbial life in the soil: bacteria and fungi. All soil (and therefore all compost) needs both, though what grows best depends on which predominates.
- The most plentifully available materials for composting are grass mowings and other green matter in the summer, leaves in the autumn. Green materials encourage bacteria, supporting annuals – including vegetables. Dead leaves (and other ‘brown’ materials) encourage fungi, which support trees, fruit and other perennials.
- Mycorrhizal fungi have existed for far longer than plants with roots. Both plants and the soil that they grow in depend on these underground mycelial networks, which grow into the plants’ root systems and have a much longer reach than the roots themselves. They can deliver both nutrients and moisture to the plants that they ‘team up’ with, and in return the plants provide sugars (derived from photosynthesis) for the fungi.
- The same fungal networks can transmit information through the soil, by delivering particular chemicals from plant to plant or tree to tree. This has become well known as the ‘wood wide web’.
- These networks are damaged by tillage – ploughing and digging – and ‘no-dig’ methods lead to far healthier soil. Growers such as Charles Dowding use a combination of composting and no-digging to very good effect.
- Bare soil dries out too much in hot weather and gets too cold and wet during the winter. Soil is best kept with living plants growing on it all year round, with green manures (or ‘cover crops’) used between food crops. This maintains beneficial microbial activity, which needs growing plants to keep the underground system alive.
‘For the Love of Soil’, Nicole Masters. [Regeneration of soil damaged by modern farming methods].
‘Grass-fed Nation’, Graham Harvey. [Livestock husbandry and countryside regeneration].
‘Entangled Life’, Merlin Sheldrake. [Fungi and their importance to the world’s ecology].
‘Teaming with Microbes’, Jeff Lowenfels. [Regenerative practices on a back garden scale].
Free webinars put out by the Soil Food Web school: email@example.com