Without the top few inches of topsoil on the earth’s crust, life on earth would not be possible as we know it. In fact, we wouldn’t even be here on Earth. Unfortunately, as a species we don’t fully appreciate this important fact and have played a massive role in the destruction of topsoil. Since the 1960’s nearly one third of the global arable land area has become degraded and according to the Soil Association 10 million hectares of land are abandoned every year due to soil erosion.
During the International Year of the Soil in 2015, we campaigned with the People for Soil Campaign for some legal protection for soils. We tried to raise awareness about the importance of protecting this most valuable resource we have on Earth but we failed. There is still no legal protection for Soils. There is detailed EU protection for air, water and other natural assets but not for the most important being on Earth – The Living Soil. Imagine, 95% of all our food comes from soil and also fuel, clothing and so much more.
How is it possible that everyone is aware of climate change and rising sea levels but no one seems to be aware that we have only 60 harvests left if we continue to farm the way we do now. These are figures from the United Nations WHO.
Now we are in 2023 and there is still no legal framework for protecting our soils. The ironic truth is – if we were to make our soils fertile again and we can only do this by bringing carbon back into the soil through compost or manure. The carbon would be taken from the atmosphere and deposited into the soil. So maybe we should all become soil warriors rather than climate warriors?
We really can’t afford to lose any more with an ever increasing world population. Thus our most important task in the world is to preserve and enhance our soils so they can keep producing sufficient food for the future. Wouldn’t it be a wonderful lifetime’s achievement to leave a plot of land in better health than when we found it?
Mother Earth
It can be quite difficult to get a thorough understanding of soils, partly because the players and mechanisms are nearly all invisible to the naked eye and soil scientists don’t often have the knack to explain it in ‘normal’ language.
We need to make a mental choice and start treating soil like ‘Mother Earth’ – with care and respect. The American word for soil ‘dirt’ is really the ultimate insult for the giver of all life.
In the end, everyone and everything will end up as new particles of soil.
Serotonin for gardeners
There is one thing that a lot of vegetable gardeners agree upon: we all know that when we’re working in the garden and getting our fingers dirty, all our worries and stresses seem to fade away. Researchers from the Bristol University and University College London found out the reason. Apparently there are friendly bacteria that are quite common in a fertile soil that actually activate brain cells to produce the brain chemical serotonin. Low levels of serotonin are linked with various disorders including anxiety, aggression, depression to mention a few.
So now we finally have the proof of what we already know – gardening cheers us up! Just take off your gloves and even your shoes and spend more time getting dirty.
Understanding soils
The soil in your garden or farms can vary quite a lot. There may be patches of excellent soil where a garden once was or rocky, stony patches where rubble was buried.
In order to find your ideal spot, take out your spade and dig a few large holes in different places in your garden. Compare the sods (spade depth) and look out for the following things:
Colour of the soil (the darker the better)
Texture (see below)
Is it loose or compacted (see how easy it crumbles)
Are there any worms or worm channels
Are there many plant roots (do they penetrate deeply?
Is there orange mottling (this is iron that has oxidised and indicates temporary waterlogging)
If you dig a little deeper you can see your soil profile. You should dig about 50cm deep and 50cm wide. This will give you excellent information on the depth of your soil. A soil is made up of topsoil, subsoil and the underlying rock. There is usually a clear difference between the topsoil and subsoil.
The topsoil usually has:
A darker colour
A looser structure
Plenty of worm and insect channels and plant roots
The subsoil is lighter in colour, compact and with very few traces of life.
You should easily be able to identify the layers and measure the depth of your topsoil. A depth of 30cm of good topsoil would be more than perfect. A depth of 20cm is sufficient but more care and effort is required to improve it. Anything less than 20cm you’ll find that your crops will be struggling and you should definitely invest in raised beds.
Soil Texture
Many people mix up the terms soil structure and texture. The texture of a soil is determined by the amount of sand, silt and clay particles present. These are classified according to their size with sand being the largest and clay the smallest particle.
Sand: 0.06 – 2mm
Silt: 0.002 – 0.06mm
Clay: less than 0.002mm
Over hundreds of thousands of years rocks have weathered down into small particles and these form the main ingredients of most soils (peat soils are the exception).
Clay soils are sticky when wet and hard as rock when dry. They are very difficult to work. On the positive side they are less prone to leaching and thus are nutrient richer soils.
Silty soils are reasonably moisture retentive but can compact easily.
Sandy soils are very free draining, easy to cultivate and warm up early in spring. Unfortunately they can’t hold water and nutrients very well.
Luckily most soils are made up of a mixture of sand, silt and clay particles. An even mix would be the ideal.
There are two easy tests to identify what texture your soil is:
Jam Jar Test
Get a large jam jar and half fill it with crumbled up soil, add some water and shake it vigorously and let it settle. The sand particles will settle within a minute, the silt particles within an hour and the clay particles within a day. The next day you should be able to see clear layers of the different particles and their proportions.
Finger test
Take a small handful of moist soil and rub it between your thumb and fingers. If it is smooth and sticky and can be rolled into sausage shape it’s a clay soil. If it feels gritty and can’t even be rolled into a ball it’s a sandy soil. A silty soil has a soapy silky feel when rubbed and leaves the fingers dirty. A peaty soil looks very dark and has a spongy feel.
Now here comes the important information:
Any soil can be improved by compost or composted manure application!
Soil Structure
The fertility of your soil depends largely on the soil structure. If the soil is crumbly and can be worked easily, then your plants will be thriving. A well-structured soil consists of crumb particles which join the lumps of mineral and organic particles together.
The first thing to do is to pick up a handful of soil and feel it, smell it and see how easy it crumbles.
A dream soil is one that smells sweet like forest soil, is dark in colour and crumbles easily when rubbed between your fingers. It should let the water penetrate easily and also hold moisture in dry weather. It should have sufficient nutrients including trace elements that are available as and when plants need them.
The important fact is that any soil can be significantly improved over a number of years if it is well managed and cared for.
Life in the soil
It is very difficult for us to fully appreciate what goes on in the soil. If we could only see the creatures toiling away relentlessly we would probably take better care of it. A healthy soil is teeming with life. They are tiny, but seen through a microscope, they open up a fascinating world of wonders. In one gram of soil, the number of bacteria ranges from 100,000 to several billion.
In one hectare of good agricultural land (100m x 100m) there are: 20,000kg Microorganisms, 370kg Protozoa, 10kg Springtails, 50kg Millipedes and woodlice, 17kg Insects, beetles and spiders, 4,000kg Earthworms.
All those soil organisms play a significant role in maintaining a healthy fertile soil. If these organisms were not present the soil would have no life – it would die. Their role is to break down the crop residues and other natural inputs and mix them with the soil. As they break down the waste, essential plant nutrients are being made available to plants.
There is another great invention of nature: the warmer the soil, the more active these microorganisms are and the more nutrients they release. That’s also when plants need more nutrients. So how do we encourage these creatures? We simply feed them with compost, manure, crop residues, seaweed, weeds, etc.
The founder of the Soil Association, Lady Eve Balfour, wrote in 1943:
‘The health of man, beast, plant and soil is one indivisible whole; the health of the soil depends on maintaining its biological balance.’
(Note: There is a lovely podcast on the life of this remarkable and brave woman on BBC Radio 4 podcast – Great Lives – Lady Eve Balfour)
An old country wisdom:
“A farmer should live as though he were going to die tomorrow; but he should farm as though he were going to live forever.”
Humanity completely depends on the soil for our survival on earth. There is nothing greater we can do than to leave a plot of land more fertile than we found it.
This is what we have to understand: what we take out from the soil we have to give back.
Soils can counteract global warming – Soils act as carbon sinks
Soils store 4,000 billion tons of carbon – this is far more than forests that store 360 billion tons of carbon and the atmosphere which stores around 800 billion tons.
The carbon in the soil is what gardeners often refer to as compost or composted manure from a farm. This was used for millennia by gardeners and farmers and only with the widespread introduction of artificial fertilisers after WW2 the problem started.
We have stopped putting organic matter back into the soil for 70 years and the organic matter content of soils which was often in the region of 5% has dropped to 2% in arable areas. This carbon has been released into the atmosphere.
The organic matter content is the living component of our soils. It’s everything that is and was once alive. The remainder of the soil is the mineral matter that is derived from rock particles.
A healthy humus rich soil acts as a carbon sink (carbon deposited in the soil) and can thus counteract global warming.
It’s logical if you think about it. Plants absorb (breathe in) carbon (a greenhouse gas) from the atmosphere and when you compost the plants (or anything else) this carbon is going to make up the organic matter or humus which is quite safely stored in the soil for many years and some of it even for many decades.
So, the most active way to counteract global warming is to compost every bit of waste which is decomposable.
I’m sure that within a decade people and countries will get grants to grow crops for composting which will act as carbon sinks (absorb and store carbon).
What can gardeners do to combat climate change?
Our main priority should be to increase the organic matter content in the soil. This way our soils become a lot more fertile and productive as well as helping to combat climate change – in our own small way.
This is what we can do in the garden:
Making compost
Learn how to make great compost and use everything that can possibly be composted and even get some other ingredients from other sources.
Growing peas, beans or clover
These plants belong to the Leguminosae family and work in symbiosis with soil bacteria to fix atmospheric nitrogen. This is a free ecological service.
The production of synthetic nitrogen requires 5% of the world’s annual gas consumption – another contributor to global warming. Many farmers now realise this and sow clover into their fields and make huge savings in not having to buy nitrogen fertilisers.
Seaweed
If you live close to the coast, seaweed is an excellent garden fertiliser and increases the organic matter content in the soil. Simply put it onto the soil (unwashed) in late autumn after the crops are harvested and remove it in early spring and put it into the compost heap or spread it around fruit trees.
Green manures
A green manure is a crop that is grown and dug back into the soil for the simple reason of improving soil fertility – increasing the organic matter content and for nitrogen fixation. Examples include clovers, rye/vetch mix, phacelia, buckwheat and many more.
Mulching
Mulching with a natural material such as wood chips, bark mulch, leaves, straw and even lawn mowing around fruit bushes and other perennial crops are a wonderful method of both feeding the crops, improving soil fertility as well as bringing carbon back into the soil.
Mulching around vegetables plants may be more of a problem especially in the wetter parts of the country as a mulch often attracts slugs and snails.
No – Dig system
When we dig over or cultivate our gardens, carbon will be released from the soil. That’s why many gardeners have adopted a no-dig system and rely on mulching. I try to dig as little as possible – my test is if I can push a garden fork into the soil without using my foot – there is no need to dig.
Benjes Hedge (dead wood hedge)
That’s a great project idea. Put in stakes or strong branches in a parallel line (about 1m distance) and then back fill the gap in between with hedge cuttings, branches and any other woody material. This makes a wonderful habitat for robins and wrens who will nest in there and eventually sow the seeds after having eaten berries from fruiting shrubs. Just as important – that’s a pile of carbon slowly getting back into the soil.
To summarise: A healthy soil produces healthy vegetables, so if your plants are ailing the first question you should ask yourself, is my soil fertile enough?
Fact:
It takes 1,000 years to form 1 inch of topsoil through natural processes
Fact:
A healthy soil reduces the risk of flooding and protects ground water sources through neutralising and filtering pollutants.
Quote:
“Upon this handful of soil our survival depends. Husband it and it will grow our food, our fuel, and our shelter and surround us with beauty. Abuse it and the soil will collapse and die, taking humanity with it”.
Sanskrit text 1,500BC
Quote:
“We are using the world’s soils as if they were inexhaustible, continually withdrawing from an account, but never paying in.” (Heinrich Boell Foundation)
Klaus Laitenberger
Klaus Laitenberger is the author of three vegetable gardening books. He was the Head Gardener at the Organic Centre in Co. Leitrim and restored the gardens of Lissadell House in Co. Sligo. He is a regular contributor to the Irish Garden magazine.
Klaus also works as a gardening consultant and gives lectures and talks nationwide on growing food. His books have attained excellent reviews from other horticulturists and top gardening newspaper & magazine writers and other gardeners alike.
https://greenvegetableseeds.com/books/
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