Soil by Daphne Lambert
'A nation that destroys its soil destroys itself' Franklin Roosevelt
Fertile soil is an exquisite interplay of billions of organisms and it is this microbial bio-diversity that gives rise to the myriad forms of life that feed us. The complexity of rich, vibrant, organic soil is extraordinary. There are more micro-organisms in a handful of this kind of soil than there are people in the world; up to 1 billion from up to 10,000 species in just one teaspoon of soil!
Soil based organisms are tiny microbes that live in soil. Their many functions include digesting inorganic substances, protecting root systems from harmful parasites, yeast, and fungi and providing growth factors and different hormones. They support healthy plants by preventing contamination with undesirable organisms antagonistic to growth. Although very few of the microbial species in soil have been identified, it is known that they have evolved a complex symbiotic relationship with plants. Every bit of the plant produces food to promote the growth of bacteria and fungi and in return, the bacteria release nutrients for the plant to grow. The fertility of the soil and its ability to grow healthy plant life depends to a large extent on the levels of organic matter within it. Organic material from plants, animals and organisms decomposes and when this becomes resistant to any further decomposition it is known as humus. Unlike organic material humus is stable creating a fertile soil which is extremely absorptive, holding and releasing water and nutrients as needed. It also improves the structure of soil so that it is crumbly and aerated. Without stable humus plus decaying plant and animal matter the soil cannot support the wide variety of organisms that enables nourishing food to be grown.
The use of chemical fertilisers, herbicides and pesticides has been shown to inhibit the microbiological life in the soil which in turn affects the health of plants. Every bit of the plant produces food to promote the growth of bacteria and fungi and in return the bacteria release nutrients for the plant to grow. Swiss researchers spent 21 years comparing the soil of organic and non organic farming and dramatic differences in the mass of soil organisms was found. On the organic land the mass of micro organisms which provide delivery of nutrients to the roots of crops was 25% greater. There are 60-90% less earthworms, essential for aerating, draining and fertilising in soils treated with pesticides. The use of soluble nitrogen fertiliser results in a higher nitrogen concentration in the plant sap and thinner cell walls, increasing the susceptibility of crops to pests and diseases. When a plant is deprived of the nutrition it needs to flourish, it suffers from a depleted immune system and this in turn diminishes the ability of the plant to nourish anything that eats it.
Soil fertility affects the vitality of plants and plays an essential role in the water cycle, storing carbon and mitigating the effects of climate change. The more fertile the soil the more able water is able to infiltrate the earth’s crust and as it slowly percolates down to the aquifer and on its journey is purified by micro-organisms purify the water on its journey. When soil lacks fertility water will run off the land into rivers and waterways at the same time taking with it valuable topsoil. The formation of just one inch of topsoil takes around 500 years on agriculturally used land – we cannot afford to lose this valuable soil.
Water is a major global concern, climate change results in both increased rainfall and drought. Organic soils are able to absorb large amounts of heavy rainfall water without water logging or erosion and in a drought these soils are more capable of storing available water creating a greater resilience which is vital for global food security.
Soil is an important carbon store and it very important to keeps soil carbon where it is to help minimise the build up in the atmosphere of greenhouse gases. Soil sequestration of carbon is therefore very important in helping to mitigate climate change. Thirty years of Rodale Institute soil carbon data has clearly shown the benefits of natural farming to carbon sequestration. Reduced tillage and systems that do not use artificial fertilisers adding instead high amounts of biomass to the soil, through composting and crop rotation have a greater ability, they have shown, to sequester carbon.
Looking after our soils is critical for our survival; it is often argued that industrial intervention is necessary to grow enough food to feed our growing population. Bill Liebhardt from the University of California-Davis found that yields of organic corn were 94% of conventional yields but another example of organic tomatoes showed no yield difference. Swiss research found that there could be up to 20% less yield on organic farms however in poorer nations Jules Pretty and Rachel Hine when they researched over 200 agricultural projects converting to an ecological approach and found a dramatic increase in yield. Even if yields were lower it would not matter in terms of the long term disruption to the living matter in soil of chemical farming. Soil is integral to every living system. Without soil, life as we know it would simply not exist. We are dependent on soil; it is the planets fragile skin of soil that anchors our life on Earth.
Taken from Living Food – a feast for soil & soul by Daphne Lambert
buy direct from Penguin or bookstores
Charity no 1141277
Founding member : Daphne Lambert
Patron: Romy Fraser
Trustees : Bill van Marle, Laura Ellison, Sue Fleming, Candida Blaker
1 The Byres