Soil – it’s there, under the snow, teeming with life, waiting for spring, and it warms me just to think of what it will be like in a few months to hold some rich, humusy soil in the palm of my hand and inhale the scent of the Earth.
I started some weeks ago to do the research for this, my first blog for 2015, that I decided would be about soil. It seemed a logical progression from insects, the theme I chose for 2014. Then I found out that the United Nations, no less, had designated 2015 as the International Year of Soils and has put together all sorts of statistics and resource materials, many of them depressing - 33 per cent of the world’s soils are degraded, two hectares are being sealed under expanding cities every MINUTE word-wide – but more later about why we also do have cause for optimism.
One stunning fact in the UN material is that one tablespoon of soil contains more living organisms – 7 billion – than there are people on the planet. This is not news. The same information can be found in Pay Dirt,
by J. I. Rodale, published in 1945, a book I picked up from a remainder bin in the late ‘70s, and one that always bears re-reading. Rodale was an early proponent of sustainable agriculture and the founder of a publishing empire that would include popular magazines like Organic Gardening.
In terms of current research, there’s an excellent Soil Biology Primer on the United States Department of Agriculture website that conveys a wealth of information with illuminating graphics and pictures. Bacteria, fungi, algae, protozoa and nematodes are among the abundant and invisible lifeforms in the soil. They consume plant litter and each other and produce nutrients, they extract nutrients like nitrogen and carbon from the air, they break down pesticides and pollutants. Some cause disease in plants, others control it. Some soil-borne diseases affect humans, which is why you must keep cuts or punctures clean and protected, and boost your tetanus shot regularly.
Other soil organisms are arthropods, which include insects like springtails, beetles, and ants; crustaceans like sowbugs; arachnids like spiders and mites; myriapods, such as centipedes and millipedes; and scorpions. They shred organic matter, aerate and mix the soil, and regulate populations. There are thousands of species of arthropods in our soil.
And then there are earthworms. We all know earthworms, and I will just note than they are not native to Canada (except for one species in Quebec), and in the forest, where the decomposition process is driven by fungi, earthworms are an invasive alien that is disrupting lifecycles, most notoriously those of ground-nesting birds like the Hermit Thrush and the Ovenbird. But earthworms are tremendous drivers of fertility and on farms and in most gardens, their presence is to be encouraged.
These myriads of organisms build the structure of the soil, clumping soil particles together so nutrients are retained and also creating spaces between the particles to allow water and oxygen to penetrate. Most important, they create communities that work together and keep each other in balance. These communities include plants, and we are now learning more about how plants are active players in the soil environment.
It has been known for some time that mycchorizal fungi growing on roots perform a vital function in converting nutrients to make them available to plants. J. I. Rodale noted in 1945 that it had been thought plants were “infected” by the white strands of fungi observed on their roots until what was then “modern” research uncovered the symbiotic relationship.
In 2001, two soil ecologists at the University of Guelph took our understanding of these below-ground interactions a step further when they reported that a fungus living on the roots of the Eastern White Pine was killing springtails and that they had been able to show that the trees contained significant amounts of nitrogen derived directly from the springtails. The findings came as a surprise, because the scientists had hypothesized that the springtails might be having an adverse effect on the trees as they generally consume fungi. Instead it turned out the trees were using the fungi to prey upon the insects. “It was as shocking as putting a pizza in front of a person and having the pizza eat the person instead of vice versa,” one of the researchers told Science News.
Rodale’s mentor was Albert Howard, the Economic Botanist to the Government of India in 1905-1924. Howard was sent to teach Indians the ways of Western science, but instead learned from and supported the traditional practices of local farmers. Howard, Rodale wrote, found “the mycorrhizal association to be the living bridge by which a fertile soil (one rich in humus) and the crop are directly connected and by which the food materials ready for immediate use can be transferred from soil to plant.”
Not surprisingly, given the complexity of the relationships, soil micro-organisms occupy specific niches – at the surface, a few centimetres down, or deeper still - that we disrupt at our peril. The most obvious way we do this is by digging or tilling. Why do we do it? Because it works, in the short run. Turning the soil flushes it with oxygen, spurring a microbial population explosion and a massive release of nutrients – unfortunately far more than plants can use, so much of it leaches away - but as the crop responds to the bounty with increased production, it seems that all is well.
Payback comes in a few years, when the soil’s resources of humus and minerals are used up and the organism populations crash. The natural process of renewal, with the slow breakdown of organic matter, has been disrupted. Tilling or digging also dismantles the soil structure and turns up endless weed seeds that need further work or chemical applications. There are organic options – cover crops, allowing the land to rest in fallow, adding manure and returning plant residues to the soil - that go some way to repairing the damage, but generally the preferred solution is to apply chemical fertilizers to replace the leached nutrients as quickly as possible, and chemical pesticides to attack the disease organisms that flourish when the biodiversity of the soil is destroyed.
This is the lesson Howard learned from the Indian farmers he observed almost a century ago: “The problem of crop production is to feed the soil population – earthworms, fungi, and bacteria and so forth – who in turn feed the plant. If we look after the soil population, everything else will follow. If we try to feed the plant directly, as with chemical fertilizers, Nature’s reaction is loss of quality followed by disease.”
For Howard, the answer was compost. Fast forward to the last quarter of the 20th
century, and we have permaculture, which took the teachings of people like Howard and Rodale and pioneered techniques that follow Nature’s lead even more closely. Instead of building and moving piles of compost, the preferred methods are mulching and sheet composting. Australians Bill Mollison and David Homgren were the pioneers of permaculture, but unknown to them, a modest Japanese farmer called Masanobu Fukuoka had spent 30 years evolving the same practices on his family’s farm – practices of following Nature’s lead and letting her do the work. Fukuoka was discovered by the permaculturalists and his delightful book, The One-Straw Revolution,
was published in 1978.
Here’s a glimpse of his philosophy: “I was aiming at a pleasant, natural way of farming which results in making the work easier instead of harder. ‘How about not
doing this? How about not
doing that?’ – that was my way of thinking. I ultimately reached the conclusion that there was no need to plow, no need to apply fertilizer, no need to make compost, no need to use insecticide. When you get right down to it, there are few agricultural practices that are really necessary.”
I shall deal with how we can support our soil communities in my next blog. But first, some good news, about how people in various parts of the world are rising to the challenge of reversing environmental degradation. Thanks to Bob Bowles for forwarding this link to a series of videos
. The first, about the restoration of China’s Loess Plateau, an area the size of France, is 30 minutes long, the others are quite short. They are very cheering. They show it need not take long to fix things if you work with Mother Earth. Happy New Year. Sources
FAO – International Year of the Soil Soil Biology Primer The Mycophile – September-October 2014 Invasive Earthworms Pay Dirt
by J. I. Rodale – Rodale Press Inc. (1945) The One-Straw Revolution
by Masanobu Fukuoka – New York Review of Books Classics (2009)