For Our Children's Earth... rebuilding the soil, sustaining the future.

Earth is "the blue planet", in consequence of its large water body, which weakly absorbs light at the red end of the optical spectrum, so highlighting wavelengths at the blue end of the range. Viewed against the blackness of outer space, a very narrow blue band can be seen to encircle the globe, which represents the Earth's atmosphere, and is so coloured because air molecules scatter blue light more strongly than they do red light.The word "earth" may also mean soil, which is the fragile living skin of the Earth. Without soil, and the overlying atmosphere, with its 20% oxygen content, life on the surface of the Earth could not exist. Certainly there would be no humans.

Soil consists of a mineral component, which is generally a mixture of sand, silt and clay. Since soils vary considerably in their composition, they may be compared universally using a "soil texture triangle" http://upload.wikimedia.org/wikipedia/commons/8/80/SoilTexture_USDA.png. A good fertile soil is a loam, which has an approximate composition of 20% clay, and of the order of 40% each of silt and sand. These terms do not reflect the chemical composition of the three components, but their particle size. Thus, sand grains are of the order of millimeters or less in diameter, while clay particles are of nanometer dimension; particles of silt are of a size somewhere in between these orders. Soil also contains organic material, referred to as soil organic matter (SOM), or soil carbon (SC). This ranges from identifiable plant components, to their more indistinct decomposition products, created by passage through the bacterially replete bodies of earthworms, and by the actions of the other creatures, and microbes that live within soil http://ergobalance.blogspot.co.uk/2014/04/deep-down-and-dirty-science-of-soil.html. The mass of the living creatures themselves is also accounted in the reckoning of SOM.

Soil is indeed both fragile and living. It is fragile because it is prone to degradation, principally by erosion. It is living because it contains an amazing number of different species within it, collectively termed the soil food web http://www.sciencereviews2000.co.uk/blog_v2/view/science-progress-news/62/soil-erosion-climate-change-and-global-food-security-challenges-and-strategies/806#.VFDC3xbyVco. It is thought that a single teaspoonful of soil may contain a billion microbes. A major source of soil erosion is deforestation, which may occur naturally, e.g. through forest fires, or by human actions, to clear land to grow commercial crops on, e.g. soya beans in South America. Slash and burn methods are employed on a smaller scale by groups of farmers who are poor and need to feed their families. More exquisite methods are sometimes employed to clear ground of trees, shrubs and all else, e.g. the process of "chaining" where a ship's anchor chain, maybe 400-600 feet in length, is strung between two 100 tonne tractors. If 2 inches in diameter, such a chain will have a weight of 7-10 tonnes http://www.sotra.net/products/tables/weight-for-studlink-anchor-chain, and so by driving the tractors, the chain is dragged along the ground, where it simply rips out anything in its path by the roots.

Soil that has been so denuded is vulnerable to erosion, all the more so when it is left uncovered as a result of monoculture cropping, and during the winter, when the erosive elements of wind and water are at their most forceful. While erosion is the major (85%) cause of soil degradation globally, other impacts are important, e.g. compaction, crusting (hardsetting), loss of nutrients, contamination, salinization and loss of biological life in the soil. Once the productivity of the land has been lost, the strategy is to move on and clear yet more forest. According the the United Nations, one third of the world's cropland has been abandoned over the past 40 years due to degradation and desertification http://www.giz.de/expertise/downloads/giz2013-en-german-national-report-unccd.pdf, while 52% of the land used for agriculture is moderately to severely affected by soil degradation http://www.unccd.int/Lists/SiteDocumentLibrary/WDCD/DLDD%20Facts.pdf.44% of the world's food production systems and 50% of its livestock are considered to be vulnerable to climate change, while 12 million hectares of crop land are lost per year (23 hectares per minute), where 20 million tonnes of grain might have been grown. All of this against an estimated requirement to produce 60% more food by 2050, not only to match a population that is predicted to increase  from around 7 billion now, to 9.5 billion, but that there is a rising "middle class" who are likely to have greater expectations from their diet, i.e. want to eat more meat, which is far more land intensive to produce than growing crops to be eaten directly http://ergobalance.blogspot.co.uk/2014/04/the-soil-land-water-climate-honey-bees.html. Thus, we are destroying the productivity of that same land from which we demand a relentless increase in production: two powerful forces pulling in opposite directions, with an inevitable "give" at some point.

There is a close connection between soil and water. In the natural order of things, water evaporates from plants and wetlands (evapotranspiration), rivers and oceans, forming clouds in the atmosphere from which rain falls. The rain is absorbed through the soil surface (infiltration), and is taken up by movement through the soil (transmission): when the rates are high for both processes, the soil acts as an effective "sponge" and can absorb large amounts of water http://agroecologygroup.org.uk/wp-content/uploads/Briefing-on-flooding-soil-and-farming-pr.pdf. When the soil becomes compressed, e.g. by heavy farm machinery or over-intensive grazing, a process called "compaction", the water cannot enter it so easily and tends to move elsewhere, as "runoff". Water runoff contributes to soil erosion: when the soil is unable to retain water, it runs off the surface taking large amounts of soil with it. This soil ends up downstream in rivers (silting-up) where it creates bottlenecks and causes the water to back up. Since it is in the surface layers of the soil that nutrients, e.g. phosphate, are concentrated, essential fertility is lost from the soil in the process. Soil may also be eroded to below the optimum rooting depth of plants, which stunts their growth. Production of maize has expanded in the U.K. since the 1970s http://anewnatureblog.wordpress.com/2014/02/06/lost-in-the-drainage-maize/, mostly grown to feed cattle. The stubble is left over autumn and winter, and is not ploughed into the ground, meaning that fine soil is exposed to be washed downstream, when the impacts of wind and rain are at their strongest. Regions in the South West of England, including the catchment that drains into the Somerset Levels http://ergobalance.blogspot.co.uk/2014/02/flooding-on-somerset-levels-and.html, have some of the greatest concentrations of maize crops in the country, and it has been estimated that some 50% of the sediment in the Tone and Culm rivers are from soil eroded from fields of maize grown to feed concentrated and highly producing dairy herds.

Uplands, if well manged, can absorb large quantities of water, and planting trees and shrubs has a hugely positive effect in reducing the volume of water that ends up downstream. Rather than intensive grazing, which can urge soil compaction, a loss of vegetation and increased soil erosion, less intensive and all year round grazing can help to improve the soil structure and its all over quality. The presence of soil organic matter (SOM) is a critical feature of good soil structure and its ability to retain nutrients. This improved soil structure also enhances the ability of soil to absorb and hold water, so that a high SOM content can make a dramatic effect in the capacity of soil to hold and transmit water, while the loss of SOM has a large and detrimental effect on the holding capacity of soil for water and its ease of becoming compacted. In simple terms, a good soil is like a springy sponge, and in its ability to hold water, not only is runoff retarded but the lower lying aquifers are able to recharge, so preserving supplies of freshwater, as well as mitigating surface flooding. As a point of note, however, in some locales that were inundated during the 2013/2014 winter, in the U.K., even after the surface flood-waters had been pumped away, flooding still remained a problem due to "groundwater pressure", where the raised water table pushes up through the ground, and up through the floors of houses that have only floorboards as their ground-level barriers, rather than solid concrete.

In a 1937 letter to U.S. State Governors, urging soil conservation laws, President Franklin D. Roosevelt wrote, "The nation that destroys its soil destroys itself." This was around the time of the dust bowls that arose in the northern United States and Canada, where former prairie lands had been turned over to farming. The impact of ploughing, loss of prairie grasses, and drought literally caused the soil to blow away. The resulting effects on the populations were dramatised by John Steinbeck in his "Grapes of Wrath", where some 2.5 million people were displaced as they made their way toward California, looking for work and for land on which they could grow food. Good soil has been described as "the real World Bank", meaning that it is the one thing, of all things, that we must invest in. Without soil we have nothing.

The main critical factor in mitigating soil erosion, is to keep it covered throughout the year. In Utah and Montana, it has been demonstrated that ground cover has a profound protective influence, and for uncovered ground some 17 tonnes of soil/hectare/year can be lost http://www.stopclearcuttingcalifornia.org/bca/research/Ecology%20of%20Soil%20Erosion.pdf (Figure 1). This amounts to an annual loss of soil depth of about 1 mm, and at this rate, about one inch of soil would be lost in 25 years. However, this decreases markedly with increasing ground cover, so that it is nearer 1 tonne/ha/year for 100% coverage. At around 0.1 mm/ha/yr (about the thickness of a human hair), this implies that it would take 250 years to lose that same inch of soil. Under natural conditions, soil is created at a similar rate to that at which it is eroded, and it takes 200-1,000 years to form an inch of soil, depending on climate. Thus, by covering the ground, the rate of erosion is brought back to the natural balance point, rather than it being lost at 10-40 times the natural rate, as it is on agricultural lands presently.


The following are some notes, taken from a talk that I give on the broad subject of soil and other resource depletion and what we might do to cope with it. The emphasis is on Permaculture and the Transition Towns movement, so to move from the global village to a village of globes, i.e. to more resilient, self-sufficient localised communities.

Some ways to protect and regenerate soil:


•No bare ground. Reforestation (Plant Trees!). Planting cover crops (peas, beans, buckwheat, clover, etc.).
•Building Soil Organic Matter (SOM). No-till farming.

•Shielding the soil through the use of sand fences, shelter belts, woodlots and windbreaks. Plant Trees!

•Farmer-Managed Natural Regeneration: “reforested” five million hectares barren land (Niger) → 40 trees/hectare.

•Protecting forests: soil/carbon plus “lungs of the Earth”.

•Mulch from pruned trees, and straw to cover fields: increasing soil water retention and reducing evaporation.

•Plant Trees! Help soil to absorb water, reduce flooding.

•Building the “Soil Food Web” (one billion microbes/tsp.).

Permaculture. http://en.wikipedia.org/wiki/Permaculture


•Permaculture = Permanent (Agri)Culture.

•Permaculture = a good design!

•“You cannot solve a problem from the same consciousness that created it. You must learn to see the world anew.” Albert Einstein.

•Seeing the whole picture, and placing design elements together to support one another.

•“The problem is the solution.” 

•Companion planting; no-till, building soil structure, efficient use of water, smaller PNK inputs; capturing carbon; best use of light; exploit “3rd dimension”.

•“Three sisters”: bean + corn + squash.

Forest Garden (Principle of “layers”). http://en.wikipedia.org/wiki/Forest_gardening

A forest garden is a beneficial arrangement of plants etc. that exploit the 3rd dimension, both above ground and below it, in terms of the different rooting depths of plants. Such an arrangement can be highly productive.

The world’s woes… (the “changing climate”).

 •Carbon emissions – climate change. 

•Peak oil/Globalization. Population: 9.5 billion by 2050. 

•Declining resources: water, oil, gas, coal, uranium, metals, phosphorus. 

•Land degradation: soil erosion – desertification. 30% of global arable land abandoned from erosion. 

•Health: Obesity - sugar in diet, lack of exercise. Unemployment. Community?

“Nature deficit disorder”?

•Increasing poverty: rising food costs - imported fertilizers – unfair global trade practices. 

•Unstable global economy. Resources: the real limits of growth?
 

All are symptoms of a single problem – excessive (once-through) consumption.

•PRESENTLY: “The sins of the fathers”, an impoverishing scenario where finite resources are exhausted year on year, and the Earth increasingly polluted by those same processes that consume them, e.g. carbon emissions. 

•GROWTH: “growing our way to hope”, where growth is possible, if not globally, on the local scale. Resource resilience, as opposed to resource depletion.Transition Towns.

•Using permaculture, can provide much of our food and materials on the local scale, with greatly reduced inputs of crude oil, natural gas, fertilizers, and freshwater. 

•Soil is rebuilt from carbon taken out of the atmosphere, thus acting to ameliorate climate change. A win-win situation!

 "If every university on Earth was destroyed we would lose nothing. If we lose the forests, we will have lost everything”
(Bill Mollison, founding permaculturist).

 •Currently our universities are educating a generation for a future that won’t exist: http://www.rba.co.uk/UniversityShambles/.

 •Far fewer universities. Many will transform to teach more practical subjects. More local colleges and schools. 

•Need to introduce life-skills from early school.

 •We’ll need more electricians, plumbers, carpenters, bricklayers, mechanics, cooks, farmers and gardeners. NOT 50% university graduates.

•“Transition Education” – schools, colleges, universities – rooted in sustainability, will provide the re-skilling to build self-reliant communities, and enable us to escape from global collapse: climate, economy, resources.

 •Bottom-up (“grass roots”) approach, less reliant on central government.

"Circular Economy" - Event by Reading Climate Action Network (May 14th, 2014)

This event was a great success. Powerpoint presentations etc. from it are available at this link: http://www.readingclimateaction.org.uk/news-events/events/details/231

I am a board member of the Reading Climate Change Partnership, who are involved in this event, which I will be giving the introduction to.

(N.B., "Reading" refers to the large town in south east England, not the practice of mentally assimilating text!)

Reading Climate Action Network – event on Circular Economy

Wed 14^th May 9am – 11am, Apex Plaza, Reading, Berkshire U.K. 

The Reading Climate Action Network is a new venture focussing on reducing the carbon emissions of Reading, and preparing for the impacts of climate change.

Our first event will focus on the Circular Economy.  Tracey Rawling Church from KYOCERA Document Solutions / Reading Climate Change Partnership, will be giving a presentation introducing the Circular Economy and highlighting the opportunities created for businesses by this exciting new model*.   

Reading Repair Cafe will be our featured local case study presented by Rachel Miller from Transition Town Reading. Launched in October 2013, this cafe has been held monthly giving everyone the opportunity to bring items for repair, while picking up the skills to repair things themselves.

Shoosmiths Corporate Responsibility Consultant, Nicola Ellen will talk about why the firm has signed up to the RCAN challenges and what they have committed to doing.

The Climate Change Partnership will give an overview of progress on targets in the Reading climate change strategy action plan.

Kindly hosted by Shoosmiths LLP   

Places are limited. 

To book please email you name, organisation, position and contact details to climate.change@reading.gov.uk. For more information please call 0118 937 2100.

To find out more about the RCAN, RCCP and Climate Change Strategy, please visit www.readingclimatenetwork.org.uk  

Online invite:

http://readingcirculareconomy.eventbrite.co.uk

* The Circular Economy is a restorative economic model that aims to deliver maximum economic value with minimum consumption of resources, with a focus on efficient cycling of materials, increased use of renewable energy and business model innovation. Find out more: http://www.ellenmacarthurfoundation.org/

Deep Down and Dirty: the Science of Soil.

This is such a brilliantly crafted programme (http://www.bbc.co.uk/iplayer/episode/b040y925/Deep_Down_and_Dirty_The_Science_of_Soil/ Video now removed), that I decided to summarise its contents here (along with my own comments). The microscopic photography is just amazing https://www.youtube.com/watch?v=gYXoXiQ3vC0, revealing the structural components of soil in intricate detail: grains of sand, silt and clay, and the creatures that live in it, most of which are invisible to the naked eye: nematodes, protozoa, mites, bacteria, fungi etc. http://www.ncbi.nlm.nih.gov/pubmed/23469709 It is its soil that causes the world to spring into life, in this eponymous season, awakening from a winter torpor. Originally the Earth was barren rock, but was transformed into a vibrant living planet by soil. So where did the soil come from and why is it so important? What is it that gives soil its amazing life-generating force? In a forest, everything is supported by what is inherently in the ground, whereas in a human-tended garden or farm, fertilizers are added to replenish what is lost from the soil. In the forest too, those nutrients must also be replaced, but this is largely accomplished through the symbiotic balance of natural processes.

The forest floor is covered with leaf litter from last season's life. Plants cannot use this to grow on, because the fallen leaves are too tough to be broken down and digested: thus, any nutrients they contain are locked within them. Samples taken using a soil-corer reveal intact leaf litter as a top layer, but below that is a much darker layer where the particles are smaller and much more broken down, and below this is topsoil. The different layers are described as soil horizons and collectively as the soil profile. Below this, the individual components disappear, so that the trapped nutrients are ultimately released into the soil. The key organism for breaking down the leaf litter is a fungus: strictly, mycelium - the vegetative part of the fungus - which we often observe as fine, white threads that grow out from dead wood, leaves etc. The mycelium releases enzymes to break down wood or leaves. Fungi are the only organisms on Earth that can decompose wood. As the fungus breaks down the wood and leaves, a rich material called humus is formed.

The fungus also feeds an entire world that we are not normally aware of, called the soil food web http://www.ncbi.nlm.nih.gov/pubmed/23469709, consisting of millions of tiny creatures, all of which are dependent on the nutrients released by the fungus. There may be a million different species of organisms in the soil, including bacteria, nematodes, protozoa, mites (arthropods), tardigrades (water bears), and rotifers (with a tail that appears to revolve like a wheel). A single teaspoonful of soil may contain a billion different organisms. As they eat, and are eaten themselves, along with their excrement, these creatures disperse nutrients that were initially released by the fungi. Breaking down all these tough materials is too hard a job for the fungi to do alone, and earthworms are their greatest ally. The earthworm has been called an ecosystem engineer. There may be two million earthworms in an average field. Charles Darwin studied earthworms for over 40 years, fascinated by the question of why they are so important in soil. While the majority of the organisms in the soil are invisible, it is not necessary to make recourse to a microscope to determine the health of the soil food web, since the abundant presence of earthworms is a clear indicator that all its members are present in mutual harmony.

Earthworms dig burrows in the soil, which provide air for everything that lives there, they digest dead leaves, unlocking their trapped nutrients, and they excrete the black-brown material that is a visible component of the soil. Worm-casts are frequently visible on the soil surface: calling-cards from the nocturnal adventures of earthworms. Nothing is faster than an earthworm in breaking down plant matter, and in an average field one and a half tonnes of plant matter are processed every year. Yet they look like a simple fleshy tube, so what's going on inside the worm? It turns out that the worms are full of bacteria, and so the worm ingests the leaves and the bacteria finish the job of breaking down the plant matter. The worm produces mucous/sugars that the bacteria like to feed on, and the conditions inside the worm of moisture and pH are ideal to support the bacteria. Inside the worm the concentration of bacteria is 1,000 times greater than exists in soil. There is more life within the soil than on and over the ground above it. A complex system of animals, fungi and bacteria work to cycle nutrients from the dead to the living and keep the soil fertile to support the life above. Soil is maintained fertile by the continual creation of new soil.

This amazing synergy occurs in the upper layers of the soil, and we might ask whether soil consists only of plant material? By taking soil and heating it very hot with a blowtorch flame, it is found that some 30% of its mass is lost, i.e. that from organic matter (plus adsorbed water), leaving 70% which is the mineral component. The soil particles disintegrate during the process. On looking at depths below the topsoil, exposed from a landslip, the profile of layers (soil horizon) is visible. At the top, there is topsoil, roots etc., but on going successively further down, the dark organic material is seen to disappear, and the deeper layers consist mainly of fragments from the underlying rock. Finally there is bedrock, which is the foundation of soil development.

The largest soil particles are sand (seen as round grains, of millimeter to sub-millimeter dimensions), while the smallest particles are clay (of nanometer size); silt is of an intermediate particle size (of the order of microns). In relative terms, if a sand grain were the size of a beach-ball, a clay particle would be a pinhead. The particular composition of a soil determines the behaviour of that soil and most importantly how it supports life. By comparing three cylinders, filled respectively with sand, silt and clay, water is seen to percolate relatively quickly through sand, but only very slowly through clay, while the silt is somewhere in-between. This demonstrates drainage, or how well water can move through different kinds of soil. Within the clay, the gaps where water can penetrate are exceptionally small, hence the tortuous movement of water through it. Indeed, using scanning electron microscopy, it is apparent that in a clay the particles are so small that there are no defined spaces between them, whereas there are clear gaps between the sand and silt particles that water can move through.

Particles of clay have tremendously greater surface areas than those of silt or sand, and also carry a surface electric charge. This means that nutrients and water are attracted and held to the clay surface, from where they can be taken up by plant roots. There is a compromise, in that if there is too much clay, the soil acts like a sponge and quickly becomes waterlogged, while the water runs through sand too quickly, leaving the soil dry. An ideal soil has all three components, with adequate but not too rapid drainage, and enough clay to retain nutrients and water. In an ideal soil, all three components work together, to support the microbes etc. that live within it. Good soil can support all plant life on earth.

How did the very first soil come to exist? In the past, glaciers would have scoured rock clean of any previous soil. What could begin to break up something as seemingly permanent as rock? Water pooled in the rock fissures and expanded when it froze, providing sufficient force to break the rock apart - this is called physical weathering. Next is the process of chemical weathering which starts with rain, which is slightly acidic from dissolved CO2, and thus can dissolve the limestone component of the rock. When the limestone is dissolved, sediments remain. The sediments are not yet soil, but it is the growth of lichens on the rock that begins the process of soil formation in earnest. A lichen may be thought of as a fungus and an algae in one body. The fungal part of a lichen can chemically attack the rock, by the excretion of an acid. Over time, generations of lichen grow one on the other, the new on the dead, while the dead remains form organic matter and when this mixes with the sediment, soil results.

From barren limestone, the processes of weathering and biological activity generate soil. The different regions show that in some cases the process is just beginning, whereas in others it has been ongoing for thousands of years. Soil is the boundary where the barren rocks meet the riot of life above. The whole provides a complex ecosystem, where life creates soil, breaking down organic matter and forcing rock apart, and yet that life is dependent on the same soil for shelter, nutrition, habitat and anchorage. A delicate balance therefore exists in the life of the soil: challenge one and you challenge the other. However, a new and mighty force has impacted on the soil: Humankind. We have mined soil, built on it, farmed on it, and in places drained it. Our actions have had consequences we never imagined.

In East Anglia the fen-land has been drained into the sea, using dykes. As the U.K. population grew, rivers and lakes were drained to plant crops. It had been long known that when land was drained, it tended to sink. Holme Fen is the largest lowland birch woodland in the UK, and on the edge of the former Whittelsey Mere basin. In 1851, the mere was drained, with the result that the raised bog, reedbed and fen habitat, which would have surrounded the mere, dried out and collapsed over time leading to the formation of the birch dominated woodland of Holme Fen http://www.naturalengland.org.uk/ourwork/conservation/designations/nnr/1006079.aspx. The dramatic illustration of the degree to which that land has sunk is the Holme Fen Post, which was set at ground level in 1850, but is now 4 metres above ground level! It is fortunate that even after drainage, the land remained too wet for ploughing and, over most of the site, the peat currently retains a depth of around 3 metres.

Peat forms in wetland environments, and is waterlogged, acidic and low in oxygen. In combination, these factors impede the rate of decomposition of organic matter, which accordingly accumulates. Plants grow using CO2 from the air, and so if their remains are not decomposed when they die, they build up, providing a "carbon sink". Once the water is removed, oxygen enters the soil allowing bacteria and fungi to breathe and the organic matter is decomposed; hence, formerly stored carbon is being released into the atmosphere as CO2. It is thought that fens are losing about 4 million cubic meters of peat = 1-1.5 million tones of CO2/year, with thousands of years worth of captured carbon being converted to CO2 in a mere period of decades.

Increasing populations led to greater areas of land being turned over to the plough. Intensive farming can lead to nutrient depletion, ploughing and tilling can destroy the soil structure, while heavy irrigation can increase the toxicity of soil. These are all contributors to soil degradation, making it susceptibile to erosion from wind and water. By the 1930s, vast swathes of land had been turned over to food production from Canada down to Texas, which led to the infamous dust bowls. Intensive farming had weakened the structure of the soil so it couldn't hold itself together, and when it dried out it simply blew away. 100 million acres of land were affected, as a result of which 2.5 million people were driven off the prairies. The potential problem is far more severe now that there are 7 billion of us on the planet, or more than the total number of humans who had ever lived, up to the beginning of the 20th century, and we are over-cultivating the soil, to produce ever more food. When we talk about an impending food crisis, it is really a soil crisis that confronts us.

A farmer at Ross on Wye was brought to the brink of ruin, since massive gullies opened up in his field. The problem was that the soil had been weakened by intensive farming, and was simply washed away by the rain, taking his  asparagus crop with it. The soil was exposed the whole time, and to avoid water standing around the crop, he planted it up and down in rows, so that the water ran off, but carried soil with it, producing gullies that became ever deeper, on down the slope. Water erosion has proved to be a devastating problem in the U.K. We have had five sequentially very severe years of storms, culminating in the storms of 2013 when the U.K. suffered unprecedented rainfall, leaving regions such as the Somerset Levels inundated for months http://ergobalance.blogspot.co.uk/2014/02/flooding-on-somerset-levels-and.html.

A raindrop has a certain mass and an associated kinetic energy, which causes breakdown at the soil surface. Extreme rainfall events mean larger drop-sizes with higher kinetic energy and more damage to the soil surface, which exacerbates runoff. By planting on the diagonal, not up and down in rows, and planting grass strips between the plants, runoff is slowed down. A surprisingly effective innovation is to put straw over the ground, as a mulch, which takes the energy out of the raindrops directly and acts as a blanket to absorb some of the water and slow down the runoff. When the ground is left bare, raindrops hit the earth with sufficient force to break up the soil. Runoff water soon begins to form and carries soil way. The straw absorbs the impact from the raindrops and the runoff is vastly reduced. It is remarkable that something so low-tech as straw is as effective as this, and while these ideas are beginning to spread, commitment and effort to change and adapt will prove critical to preserving the soils.

Wheat Rust: "The Death of Grass"?

In an echo of "The Death of Grass", the 1956 novel whose theme is the progressive razing of the world's food production by a marauding and mutating virus, with apocalyptic consequences for humankind http://ergobalance.blogspot.co.uk/2012/01/death-of-grass.html, the spectre of "wheat rust" is now raised. Wheat rust is said to be a similarly devastating condition, in fact a fungus, described as the "polio of agriculture", which has spread from Africa to South and Central Asia, the Middle East and Europe, causing severe yield losses of the most important staple crop next to rice http://www.independent.co.uk/news/uk/home-news/wheat-rust-the-fungal-disease-that-threatens-to-destroy-the-world-crop-9271485.html. In writing his novel, Sam Youd, using the pseudonym John Christopher, may have been inspired by the major epidemic of wheat rust that engulfed the North American wheat belt in the 1950s, in which 40% of the harvest was destroyed. In 1999, in Uganda, the disease resurfaced, due to mutation of the fungus, despite millions of pounds that have been spent in creating rust-resistant strains of wheat. It is thought that some 90% of all types of wheat in Africa are vulnerable to wheat rust.

Properly termed "wheat leaf rust" http://en.wikipedia.org/wiki/Wheat_leaf_rust, this is a fungal disease that affects wheat, barley and rye stems, leaves and grains, with crop yields being further diminished by dying leaves which feed the fungus. The pathogen is Puccinia rust fungus: P.triticina causes 'black rust', P.recondita causes 'brown rust' and P.striiformis causes 'yellow rust'. While farmers have used strain selection over centuries to improve wheat yields, so doing to provide disease-resistant crops has proved equally important in maintaining adequate crop production. The use of a single resistance gene against various pests and diseases plays a major role in resistance breeding for cultivated crops, and many single genes for leaf rust resistance have been identified.

Wheat leaf rust spreads via airborne spores, of which 5 different kinds are produced over the life cycle: uredospores, teleutospores, and basidiospores develop on wheat plants and pycnidiospores and aeciospores develop on the alternate hosts. Moisture is a key element for successful germination, for which optimum conditions are 100% humidity and a temperature of 15-20 degrees Centigrade. Within 10 – 14 days of infection, the fungi begin to sporulate and symptoms become visible on the wheat leaves, while the plants are entirely without symptoms prior to sporulation. In the Asian subcontinent, the spores cannot survive the hot dry weather but are re-introduced year on year from the Himalayas or surrounding hills, originating, so it is thought, from Berberis spp, Thalictrum flavum and Muehlenbergia huglet, which is a major cause of bread moulds.

Rust epidemics have been compared to a forest fire, in that once they take hold, the loss of crops is rapid and widespread, since millions of wind-borne spores are produced by the fungus, each of which has the capacity to initiate a fresh infection. The race is on to find new disease-resistant seed varieties of wheat, for which the legacy nations are better provided than developing countries such as those in Africa. A central part of this strategy is the use of Genetically Modified (GM) crops, including cloning resistance from wild grasses and barley, as opposed to using ever more virulent chemical pesticides. Mathematical models are being developed to predict potential outbreaks of wheat rust in African and Middle Eastern nations, to determine which may be most vulnerable.

Part of the problem is blamed on climate change, and the spread of two types of the fungus is thought to be a result of its adaptation to a warmer environment. Thus, outbreaks have been born in regions with no history of the disease, stretching from North Africa to South Asia, transmitted via spores carried by wind and through the soil. Such crop infestations can be added to the nexus http://ergobalance.blogspot.co.uk/2014/04/the-soil-land-water-climate-honey-bees.html of other afflictions upon the human capacity to survive and thrive, and most likely are exacerbated by modern industrialised agriculture and its practice of monoculture cropping. By default or more desirably by design, humankind may find itself steered onto the path of agro-ecology, regenerative agriculture and permaculture http://www.ncbi.nlm.nih.gov/pubmed/23469709, and away from a global food production system which is patently unsustainable.

The Soil, Land, Water, Climate, Honey Bees, Oil, Food Nexus: Peak Soil.

There is a tendency for humans to perceive ill occurrences as separate events, rather as the Biblical plagues of Egypt: water into blood, frogs, lice, wild animals or flies, deceased livestock, boils, storms of fire, locusts, darkness and death of the firstborn. Scientists now believe that the latter are historically true, but they were in fact all results of a single cause: not the wrath of a punitive God, but climate change http://www.telegraph.co.uk/science/science-news/7530678/Biblical-plagues-really-happened-say-scientists.html. Modern humans are aware of contemporary global menaces: a changing climate, peak oil, a dodgy economy that could collapse at any moment, and the extinction of honey bees, but relatively few of us know that the world's productive soils are also under threat. What has been most noticeable is that the price of food and fuel has increased markedly over the past decade, during when we have also experienced an economic crash. We fear another such shock, even amid whispers of "growth", which can only be expected to be of a slow stuttering kind, since we cannot significantly grow our rate of production of resources. Thus, the price of a barrel of crude oil has more than trebled since 2004, while global production has practically flat-lined at around 75 million barrels a day over that same period, leading to the view that we have reached the ceiling of our oil supply http://www.rsc.org/chemistryworld/2014/02/peak-oil-not-myth-fracking.

Given that all components of human civilization are inextricably linked to petroleum, either as a chemical feedstock or a fuel, if we cannot elevate our production rate of oil, nor can we grow the global economy. The fundamental fragility of the human condition, however, is more profound, since we are steadily using-up Mother Earth's bestowal to us of fertile soil. This has been dubbed "peak soil" http://www.theguardian.com/environment/earth-insight/2013/jun/07/peak-soil-industrial-civilisation-eating-itself in analogy with "peak oil", and while the two phenomena are not of the same kind, they are connected, as indeed are all the elements listed in the title of this article: soil, land, water, climate (change), honeybees, oil and food. Alice Friedmann wrote, in the context of the unsustainable nature of growing land-based crops and producing biofuels from them: http://greatchange.org/bb-alcohol1-friedemann.html

"Iowa has some of the best topsoil in the world, yet in the past century it's eroded from an average of 18 inches to less than 10 inches (Pate 2004, Klee 1991). When topsoil reaches 6 inches or less (the average depth of the root zone in crops), productivity drops off sharply (Sundquist 2005). Soil erodes geologically at a rate of about 400 pounds of soil per acre per year (Troeh 2005). But on over half of America's best crop land, the erosion rate is 11,000 pounds per acre, 27 times the natural rate, and double that on the worst 7% of cropland (NCRS 2006), partly because farmers aren't paid to conserve their land, and partly because hired farmers wrench every penny of profit they can on behalf of short-sighted owners."

This is deeply disturbing, all the more so because rates of erosion that are in excess of the natural rate of soil formation are not restricted to Iowa, but are a global feature http://www.soilerosion.net/doc/what_is_erosion.html. According to a report by the World Resources Institute (WRI) some 20% of the world's cultivated areas are afflicted by land degradation http://pdf.wri.org/great_balancing_act.pdf, and in order to feed Humankind over the next 40 years, food production must be increased by 60%. This conclusion is drawn, in part, from the expectation that another 2.5 billion people will be added to the current number of just over 7 billion of us, and that a rising middle class will have greater expectations of their diet, particularly in wanting to eat more meat. The amount of food that is wasted is another consideration, and combining this factor with population increase suggests a daily gap between the demand for food and what is likely to be available by 2050 of 900 calories (kilocalories) per capita.

Many of the limitations to meeting such a testing challenge are those implicit to the modern industrialised agricultural system per se. The factors involved are complex and inseparable, in short providing a nexus. The impact of climate change adds further weight to the problem, and seven clear courses of action have been identified, by which we might adapt to ensure food security into the future http://cgspace.cgiar.org/bitstream/handle/10568/10701/Climate_food_commission-SPM-Nov2011.pdf?sequence=6. 24% of anthropogenic greenhouse gas emissions are from agricultural activities, including methane from livestock, nitrous oxide from fertilizers, carbon dioxide from running tractors and combine harvesters etc. and from changes in land use. Furthermore, 70% of all human water consumption is claimed by agriculture. In the last 40 years, 20 million square kilometers of land have suffered degradation, which accounts for around 15% of the total land area of the Earth, while 30% of the originally available cropland is now unproductive. As noted for Iowa, the degradation of topsoil is occurring many times faster than the rate at which soil is generated by Nature, which may take 500 years to form just an inch of it http://www.theecologist.org/blogs_and_comments/commentators/other_comments/2150973/peak_soil_act_now_or_the_very_ground_beneath_us_will_die.html

There is an increasing pressure on water supplies too, which may begin to struggle in meeting demand in the food basket regions of the Americas, west and east Africa, central and eastern Europe, Russia, the Middle East and south and south-east Asia, within only 12 years http://pdf.wri.org/great_balancing_act.pdf. As alluded earlier, the costs of both fuel and food have risen markedly over the past decade: food prices follow oil prices because oil and gas are involved at all principal stages in the food production and distribution chain. The World Bank has proposed restricting oil prices as a means to mitigating food price increases http://www-wds.worldbank.org/external/default/WDSContentServer/IW3P/IB/2013/05/21/000158349_20130521131725/Rendered/PDF/WPS6455.pdf There appears little doubt that oil prices will remain high, and most likely rise considerably, since the global oil supply will increasingly be provided from unconventional sources, e.g. producing shale oil by fracking, tar sands  and (ultra)deepwater drilling, all of which have poorer net energy returns than does conventional crude oil http://www.rsc.org/chemistryworld/2014/02/peak-oil-not-myth-fracking. Indeed, were the price of oil not as high as it is currently, no one would bother to produce it from such expensive and demanding sources. There is also the critical question of how high an oil price the economy can bear, before it falls into recession and finally collapses http://www.rawstory.com/rs/2013/12/23/former-bp-geologist-peak-oil-is-here-and-it-will-break-economies/

According to the U.S. National Agriculture Statistics there has been a decline from about 6 million bee-hives in 1947 to 2.4 million in 2008, representing a reduction by 60% http://ecowatch.com/2013/06/11/worldwide-honey-bee-collapse-a-lesson-in-ecology/. Over the past 10 years, beekeepers in both the U.S. and Europe have reported annual hive losses of 30%, and last winter losses of 50% in the U.S. were not uncommon, with worst case examples of 80-90% http://www.theguardian.com/environment/earth-insight/2013/jun/07/peak-soil-industrial-civilisation-eating-itself. Since about one third of world food production is due to pollination, largely by bees, should the "bee colony collapse" continue, the effect on human nutrition could be calamitous. Various causes have been brought culpable for killing the bees, including pesticides, parasitic mites, intensive monoculture farming methods and urban development. The nexus of components that we have identified is totally at odds with providing sufficient food for a population of 9.5 billion by 2050 and maybe 11 billion by 2100 http://www.un.org/en/development/desa/population/

The various ills we have described are (as already alluded to) outcomes of the industrial nature of monoculture farming, since it frets the ecology but does not restore it, including the soil itself. Alternatively, methods of regenerative agriculture and permaculture have been advanced http://www.ncbi.nlm.nih.gov/pubmed/23469709. The latter help to rebuild the soil, making it more fertile through increasing its soil organic matter content (SOM), including establishing a healthy network of microbes and other creatures to live in it (the soil food web), thus securing fertility and crop productivity. Such methods of ecological food production can be done on a more local scale, and the food consumed closer to where it is grown, largely obviating the necessity for an extensive transportation/distribution system powered by oil-refined fuels. They are further less intensive in their demand for other inputs, such as water, fertilizers, pesticides and herbicides. By keeping the soil covered throughout the year, it is substantially protected from erosion, while the increase in SOM improves the soil structure so that it can absorb water more effectively and allow aquifers to recharge, thus mitigating both water shortages and flooding http://ergobalance.blogspot.co.uk/2014/02/flooding-on-somerset-levels-and.html. It is likely that a reduced use of pesticides, through reintroducing biodiversity, might help to bring the bees back too.