Glomalin, Biochar and the Secret of Terra Preta Soils.

I have given periodic mention to the unfolding aspect of adding "biochar" charcoal to soils, in an effort to recover some of the benefits of Terra Preta - highly rich and fertile dark soils found in South America, in which carbon (char) has been stored for hundreds of years. In addition to locking-up carbon over a long term, as noted, the soil is more fertile than the surrounding (lighter coloured) soils and has better properties in retaining water and nutrients.

Creating charcoal and assembling a kind of synthetic "terra preta nova" has the added advantage that while the charcoal is being formed by pyrolysing biomass, BioOil and BioGas are simultaneously produced. Ideally, the gas can be used as the fuel for the pyrolysis and the oil can be mixed to an extent of 25% with conventional liquid fuel, in the intention that by 2025, 25% of the U.S. oil requirements will be met by means of it: hence the name of the "25x25" club, a political group with this outcome as its primary agendum. It's a tall order and some of the estimates of how much biochar can be made are staggering, up to 9.5 billion tonnes/year, which I don't think is realistic either in terms of land use (growing enough biomass) or building bio-mass pyrolysis capacity on this immense scale. This is an estimate by Professor Johannes Lehmann form Cornell University, whose expert opinion I respect, but I don't see it personally since it amounts to producing about one tonne of biochar/hectare on two-thirds of the entire land surface of the Earth (95 million out of 150 million km^2).

The International Biochar Initiative (IBI) are working to a more modest 1 billion tonnes/year by 2050, and I reckoned recently that almost this amount could be produced in total throughout a collection of world-wide small communities in which each person made 100 kg of biochar per year - or it was collectively made for them within the activities of their community. The latter strategy cuts-down the prohibitively massive centralised plant-engineering required, if it were done this way, to more manageable chunks.

Now, there is the proposition of a connection between biochar and microbial life in terra preta soils, in which mycorrhiza fungi thrive and produce glomalin. I have noted that there is strong evidence that this glue-like glycoprotein is significantly responsible for the storage of organic matter in soil and for soil health. There is speculation that glomalin is the secret of terra preta soils/biochar as a consequence of the elevated fungal population (thought to thrive in the carbon micropores). Glomalin is produced by hair like hyphae filament structures of fungal bodies.

Overall carbon capture and humification in soil is probably the long-term process by which terra preta soils are produced and I wonder how long it would take for a soil, simply amended by charcoal, to become a fully-fledged terra preta with the properties noted. I envisage it is not likely to be an immediate event, and probably the Amazonian indians created these soils over many years, to their fully self-generating glory. The native people described the soil as physically "growing", which may suggest an accretion process involving fungi and other microbiota.

There is an interesting discussion of some of these topics at the link address below. I would be grateful for any input from those who know more than me about these things.

Related Reading.
http://bioenergylists.org/newsgroup-archive/terrapreta_bioenergylists.org/2007-February/000042.html

Peak Oil... Demand for it, that is.

Peak Oil is the global term used to describe an eventuality when world oil production reaches a maximum, and then relentlessly falls. Such "peak" models are based on an inexorable rise in demand for oil, against an infrastructural lack by which to meet that demand (i.e. you can't pump out more). Supply-demand gaps are to be expected en route but once the peak is reached, the shortfall in supply is catastrophic. As a rider to this, it should be noted that while "global peak oil" is a numerical reality - i.e. the maximum sum of barrels of oil ever produced in the world in total, in a given year - the processes of it are rather more subtle, since different fields, under the control of various regimes will peak at different times, thus shifting the emphasis of economic and political control across the globe. Those without oil will become weak and those with plenty of it will become strong - or targets for other nations who want to grab their oil.

Now, the assumption of relentless demand has been called into question in a new report entitled "The Beginning and End of Oil" by Peter Hughes, who is a director of Arthur D. Little's global energy and utilities practice. The main issues surrounding oil, climate change, security of supply, and an amplitude of market volatility that could bring economic ruin to nations and then the world, are lucidly clear. Rather than simply waiting in a spirit of foregone conclusion for these calamities to unfold, it is likely that governments will be forced to act preemptively to anticipate and provide alternatives, which will curb demand for oil.

It is a global energy-mix that is to be contrived, rather than a single solution, which there is not. The recent hike to $150 and then a crash to $30 for a barrel of oil hand in hand with the credit crunch, makes it clear to most governments that deliberately reducing our demand on oil is a policy imperative. Of all the energy-resources, oil is especially vulnerable since more than half of the world's 30 billion barrel annual count goes to fuel transportation. The absence of alternatives to oil-based fuels has cemented the outstanding stature of oil as literally empowering the engines of progress.

However, a chain of policy initiatives spanning the globe is encouraging more energy-efficient technologies throughout the transportation sector - whether on the road or in the air. High efficiency diesel engines and hybrid and regenerative breaking systems can extract more than twice the tank to wheels miles that conventional spark-ignition/petrol engines can. Meanwhile there are aircraft fuselage designs that promise savings of 30% on fuel costs, and high-temperature aircraft engines that recover energy more efficiently from fuel, so long as sufficient quantities of metals such as hafnium can be recovered to bring them to a proficient reality.

Peter Hughes, a director of Arthur D. Little's global energy and utilities practice, said:
"As the number of new policy measures implemented to reduce reliance on hydrocarbons for transportation reaches critical mass over the next 10 years, the world could see downward pressure on demand for oil and oil-products materialize much sooner than the [oil] industry would currently concede. Depending upon how quickly the transportation sector begins its migration away from oil, we could find ourselves at a tipping point in which demand for oil peaks much earlier than the industry currently anticipates, before going into long-term decline."

In the wavering scales of the energy-balance, (the report says that) oil and gas companies should reconsider the sustainability of their business models and accelerate their moves to spread into other sectors of the "energy value chain" (not a phrase I would use but is "management speak"). A greatly increased contribution from coal, natural gas, nuclear power and "other alternatives to hydrocarbons" (whatever they may prove to be) is to be expected.

The report concludes that electricity is likely to be the main supply vector for delivering energy to customers which will "create demand for multiple sources of clean power as well as the infrastructure to deliver it."

All in all, it is better to close the stable door before the horse bolts, rather than after. We will need to make the kind of changes outlined eventually, so let's begin making them now, while we still have enough conventional energy in hand to establish new paths. Probably we are involved in a game of "tag" between reducing demand and falling supply. Whichever comes first will win-out.

Related Reading.
http://www.epmag.com/WebOnly2009/item33676.php

Glomalin - Long Term Carbon Glue.

The name Glomalin derives from Glomalis, an order of common root dwelling fungi such as Mycorrhizae that colonise the root systems of plants, and was discovered only as recently as 1996. Glomalin itself is a glue-like protein which builds a carbon-rich sheath around the hyphae (thread-like tendrils) that grow out from the fungus to form a secondary root system. Glomalin contains 30 - 40% of its weight of carbon, and it is thought might account for up to one quarter of all the carbon that is contained in fertile soils. Glomalin is also a highly resistant material, and can survive being decomposed in soils for anywhere between 7 and 42 years, thus making it potentially significant in carbon storage by soils. Glomalin also helps to glue-together soil aggregates of other organic (humus) and mineral components, and it is believed to help in the formation of humus - a complex process called humification.

Glomalin gives the soil "tilth", which is a discrete texture that allows experienced farmers and gardeners to "know" good soil just by feeling its smooth granules as they run past their fingers. It is thought that glomalin may also make the hyphae sufficiently rigid they can span the air-spaces between particles of soil. It is believed that hyphae have a lifespan of days to weeks, but the much greater longevity of glomalin suggests that the current technique of weighing hyphae samples to estimate fungal carbon storage may undervalue grossly the amount of carbon stored in the soil. Sara Wright, the discoverer of glomalin, and her colleagues discovered that glomalin makes a far greater contribution of nitrogen and carbon to the soil than is made by hyphae or other soil microbes.

Dr Christine Jones, who is an independent scientist based in Australia, proposes that changes in farming methods to those of "regenerative agriculture" are necessary for the full carbon-capture potential of soil to be realised, particularly for Australian soils. She is promoting "liquid carbon pathways", in which plants pump stable carbon-rich compounds into the soil, as part of a symbiosis with root-fungi, which in return syphon nutrients and water from the soil back to the plant via their extensive hyphae systems.

The relationship between the glomalin and the humus is also symbiotic, since the glomalin contributes to the humification and the humus increases the overall fertility of the soil. Humus is an important material in the retention of water in soil. Dr Jones thinks that the assistance of the humification process by glomalin is a reason for a found much higher accumulation of carbon in some Australian soil than had been thought possible. However, she stresses, farmers may need to rethink how they farm to derive full benefits from the process. She is of the opinion that the answer lies in establishing low-input "year-long green farming" methods which maintain green, growing plants throughout much of the year.

At the University of Aberdeen, Dr David Johnson who is a specialist on mycorrhizal fungi, said:
"Many conventionally grown crops have little or no dependency on mycorrhizal fungi because they receive lots of inorganic fertilizers that don't warrant the carbon 'cost' of forming the relationship with the fungi, for want of a better expression. So, moving to low-input farming systems is likely to encourage plants to form mycorrhizas and therefore increase carbon allocation to this group of organisms." It is also known that long fallow periods, heavy tilling of soil, and a number of agricultural chemicals (including nitrogen fertilizers) can damage the fungi and other forms of soil life.

Now, there is corollary line of thinking from the United States, which proposes that it is soil-depth that is critical to whether or not no-till methods actually result in carbon storage. In essence, no-till involves leaving crop residue on the surface of the soil rather than ploughing it underneath. This saves on labour, wear and tear on machinery, soil-erosion, fossil fuels and artificial (oil and gas derived) fertilizers and pesticides, makes the soil more productive (brings it "back to life"), improves habitats for wildlife and overall biodiversity and conserves water in the soil. If the carbon input (storage) exceeds the carbon output (lost), then the method can be considered successful, or the converse if more is lost than gained.

Results from no-till studies are found to vary from region to region, and for example 40% of Ohio's cropland is good for carbon-storage. Where no-till (practised on a mere 6% of the world's cropland overall, and most of that in the U.S and Canada, Australia and South America - Brazil, Argentina and Chile) does not prove effective, other carbon-capture methods can be applied instead; e.g. mulching, cover crops, complex crop rotations, mixed farming systems, agroforestry and biochar . A survey has been carried out of no-till land in Ohio, Michigan, Indiana, Pennsylvania, Kentucky, West Virginia and Maryland by Rattan Lal and his colleagues at the Ohio State's Ohio Agricultural Research and Development Centre, where he is director of the Carbon Capture Management and Sequestration Centre. Lal says:

"Basically, those soils that are well-drained, are silt/silt-loam in texture, warm quickly and have some sloping characteristics prone to erosion are excellent candidates for no-till. Clay soils or other heavy soils that drain poorly are prone to compaction and are in areas where the ground stays cooler may not always encourage carbon storage through no-till."Lal concludes that soil depth is the crucial factor in carbon storage. He says that if you go down just 8 inches, in general, no-till fields will store carbon better than ploughed fields. However, at depths of 12 inches and more, the situation may be reversed.

"You have to go deeper," he said. "We recommend going down to as much as one metre below the soil surface... [to establish a soil ratings guide for applying different conservation tillage systems at regional and national scales].

Put another way, you have to know your soil, as farmers traditionally do. "Soil" is part of a complex interactive system, and there is not a simple "one size fits all" solution. The means must be tailored to get the best results wherever we are. The real solution is likely to be found in the sum of many smaller "solutions".

Related Reading.
[1] http://www.ars.usda.gov/is/AR/archive/sep02/soil0902.htm
[2] http://www.farmanddairy.com/news/no-till-works-but-is-not-always-applicable-for-storing-carbon/11525.html
[3] http://sl.farmonline.com.au/news/nationalrural/agribusiness-and-general/general/soil-carbon-doubts-unfounded/1465172.aspx

George Monbiot: Cats, Pigeons, James Lovelock and Biochar.

In an article entitled "Woodchips with Everything" (Published in the Guardian, 24th March 2009) [1] George Monbiot has put the cat among the proverbial pigeons now fluttering above the biochar camp, probably singing around a fire whose wood is turned partially into a form of charcoal often called biochar to emphasise its biological merits, in particular to lock-up carbon taken from the atmosphere via photosynthesis, and in the process to produce useful fuels in the form of gases and liquids (bio-oil). It is reckoned, in analogy with the original terra preta - a highly fertile black soil (hence the name) - found in Amazonia, that adding biochar to soil encourages the growth of microbes (including fungi like mycorrhiza), which further increases the gravity of carbon in the soil and makes for better soil health. The soil also retains nutrients and water better, thus relieving the impetus of demand on these increasingly restricted resources.

In his inimitable way, Monbiot opens the batting: "It’s a low-carbon regime for the planet which makes the Atkins Diet look healthy: woodchips with everything. Biomass is suddenly the universal answer to our climate and energy problems. Its advocates claim that it will become the primary source of the world’s heating fuel, electricity, road transport fuel (cellulosic ethanol) and aviation fuel (bio-kerosene). Few people stop to wonder how the planet can accommodate these demands and still produce food and preserve wild places. Now an even crazier use of woodchips is being promoted everywhere (including in the Guardian). The great green miracle works like this: we turn the planet’s surface into charcoal." Monbiot makes the point that huge areas of land would need to be turned-over to the production of biomass and biochar, and its likely negative environmental impacts:

"Carbonscape, a company which hopes to be among the first to commercialise the technique, talks of planting 930 million hectares. The energy lecturer Peter Read proposes new biomass plantations of trees and sugar covering 1.4 billion ha. The arable area of the United Kingdom is 5.7m hectares, or one 245th of Read’s figure. China has 104 m ha of cropland. The US has 174m. The global total is 1.36 billion. Were we to follow Read’s plan, we would either have to replace all the world’s crops with biomass plantations, causing instant global famine, or we would have to double the cropped area of the planet, trashing most of its remaining natural habitats."

The Article is also at monbiot.com [2]. Monbiot does make a fair point about scale, as I have contributed on this blog and my monthly column at scitizen.com [3,4] about biochar (and indeed other schemes of "geo-engineering"). The sums are enormous indeed, and I finally concluded that biochar has its best chance if it is produced within localised communities as I gave to the Guardian in a letter which they probably won't print. The Independent newspaper have published a good few of my letters but they seem more interested in detail than the Guardian, anyway you can read it here:

"Sir:
In his article (March 24th), "Woodchips with everything", George Monbiot points out correctly that growing and converting biomass to biochar and other products, on the grand scale is no mean feat. I have done the sums, and they are staggering: http://ergobalance.blogspot.com/2008/09/biochar-atmospheric-co2-mitigation.html:

The truth is that, as fossil energy wanes, we will need to live in less transport-intensive small communities - thus de-globalising the world - within which local production of biochar (including growing algae as biomass for it) is feasible. Such small scale efforts would amount to significant proportions when multiplied by the multitude of humans there is on planet Earth.

Yours sincerely,

Professor Chris Rhodes."

Now, in today's (March 26th) Guardian [5], there is a rebuttal of Monbiot's article by James Lovelock (of Gaia fame), entitled: "James Lovelock on Biochar: let the Earth remove CO2 for us," which contends that Monbiot is right that it would be a false economy to have plantations devoted to the production of biochar, but if other biomass sources - that are simply waste otherwise - could be used, then burying carbon in the ground is a good move toward addressing the problem of climate change.

Lovelock is sceptical about carbon capture and storage (CCS) strategies, e.g. from power stations and industry, but he notes:

"What we have to do is turn a portion of all the waste of agriculture into charcoal and bury it. Consider grain like wheat or rice; most of the plant mass is in the stems, stalks and roots and we only eat the seeds. So instead of just ploughing in the stalks or turning them into cardboard, make it into charcoal and bury it or sink it in the ocean. We don't need plantations or crops planted for biochar, what we need is a charcoal maker on every farm so the farmer can turn his waste into carbon. Charcoal making might even work instead of landfill for waste paper and plastic.Incidentally, in making charcoal this way, there is a by-product of biofuel that the farmer can sell. If we are to make this idea work it is vital that it pays for itself and requires no subsidy. Subsidies almost always breed scams and this is true of most forms of renewable energy now proposed and used. No one would invest in plantations to make charcoal without a subsidy, but if we can show the farmers they can turn their waste to profit they will do it freely and help us and Gaia too."

Now I like this, because it's pretty much what I was saying about small-scale biochar production in "Thinking Positive - Carbon Capture" on scitizen.com [4]. I'm pleased to be thinking along the same lines as the guru of Gaia.

The International Biochar Initiative (IBI), who are effectively the "industry body" for the biochar movement, have also issued a response to Monbiot, in a press release today [6] which makes the point that it is not fair to simply dismiss biochar out of hand because it is maybe one of a hundred different "solutions" to the environmental problems that are posed to human ingenuity on the planet. Here we are really coming back to the matter of "scale" and that making maybe 12 billion tonnes of biochar each year for the next 50 years is probably not a credible prospect. But one billion tonnes per year as the sum total of many local productions, along with several other "biological" carbon capture schemes, as I allude in my "Thinking Positive - Carbon Capture" article [4] could create a viable mix of activity.

There is no single solution to our problems either in terms of environmental pollution by carbon, climate change or the limited store of fossil fuels, most pressingly oil and natural gas, but in the combination and symbiosis of different approaches we can find a new way.

Related Reading.
[1] http://www.guardian.co.uk/environment/2009/mar/24/george-monbiot-climate-change-biochar
[2] http://www.monbiot.com/archives/2009/03/24/woodchips-with-everything/
[3] http://www.scitizen.com/stories/Future-Energies/2008/10/Biochar-----a-Miracle-to-Save-the-Planet/
[4] http://www.scitizen.com/stories/Future-Energies/2009/02/Thinking-Positive---Carbon-Capture-/
[5] http://www.guardian.co.uk/environment/2009/mar/24/biochar-earth-c02
[6] I can't find a link to this yet, but I received the IBI press release this morning by e.mail:

Press Release: IBI Response to Recent Guardian Article on Biochar March 25, 2009: For Immediate Release:

IBI has taken note of an article by George Monbiot in the UK Guardian on March 24, 2009 that questioned the validity of biochar as a climate mitigation tool and the scientists and others who support the development of biochar.

The Guardian has published responses from several of those biochar supporters mentioned by Mr. Monbiot, including James Hansen, Chris Goodall, and James Lovelock.

IBI sent The Guardian the response below written by IBI staff members Stephen Brick and Debbie Reed. For more information, contact: Stephen Brick, IBI Executive Director, sbrick5714@sbcglobal.net Debbie Reed, IBI Policy Director, dcdebbiereed@yahoo.com Thayer Tomlinson, IBI Communications Director, info@biochar-international.org


George Monbiot is right on the mark about our seemingly irresistible tendency for embracing miracle cures. And it is refreshing to have the press remind us that the laws of thermodynamics will continue to apply in our quest to reduce global carbon emissions. But his diatribe against biochar-like most such screeds-would have us throw the baby out with the bathwater.
This has been said often, but it needs to be said again: there is no magical pathway for cutting global carbon emissions. There is only a collection of steps-complex, costly, and, politically challenging. Put another way, there is no single remedy for the whole problem; but there are, very likely, one hundred different actions that can each bear one percent of the burden. Serious people have understood this for some time, and this would include, we believe, a large fraction of the general public that Mr. Monbiot presumably wishes to warn.

Biochar, produced and used appropriately, should be considered amongst the hundred. Done right, biochar produces four value streams: waste reduction, energy production, soil fertilization and carbon sequestration. Biochar can be made from animal manures and food processing wastes. These residuals are costly to those who produce them, and create greenhouse gas emissions if left untreated. Bio-gas and oil can be used for heating, generating electricity and transportation. Biochar can reduce the need for conventional, fossil-fuel based fertilizers. Finally, biochar can lock up carbon in the soils for extended time periods.

We don't have all the answers on biochar production and utilization; indeed, the mission of the International Biochar Initiative is to seek these answers, objectively and quickly. We know that there are bad ways to make biochar, that crop monoculture for producing feedstock is not a good idea, and that biochar does not affect all soils equally. None of this should rule biochar out of court, however, as we also are assembling a body of knowledge on how to produce and use biochars that are beneficial. In this way, biochar resembles many other carbon-cutting technologies that face uncertainties. In our case, all we seek is an opportunity to be heard fairly as we move towards Copenhagen. We have no doubt that exaggerating the benefits of biochar is not helpful. On the other hand, the potential of biochar deserves serious consideration. Mr Monbiot's glib dismissal of this potential is unwarranted.

Stephen Brick is the Executive Director of the International Biochar Initiative
Debbie Reed is the Policy Director of the International Biochar Initiative

Plant Nutrition.

Plants require essential raw materials to keep them going, to provide both energy and building blocks for growth. This is true of all living organisms, including humans. Carbon dioxide is absorbed from the air along with water from various sources, mainly the soil, and together the elements carbon (C), hydrogen (H) and oxygen (O) are provided. In addition to these basic units, some thirteen essential nutrients are also required for a crop to thrive: three major nutrients, three secondary nutrients and seven micronutrients.

During the past half century, there has been a depletion of the amount of micronutrients present in plants and thus available to those creatures including humans, who eat them. There is a sanguine quote from Prince Charles, who is a keen organic gardener, and runs an organic farm on his Highgrove Estate in Gloucestershire:

"The New Scientist recently reported alarming research results from a study of the long term effects of the so-called 'Green Revolution' in South Asia. New plant varieties fed with high levels of artificial fertiliser have dramatically increased food production, to no-one's surprise. But it now becomes clear that those intensively grown crops are nutritionally deficient. They lack vital trace elements and minerals, particularly iron and zinc. This deficiency has been passed on through the food to such an extent that an IQ loss of 10 points has been observed in a whole generation of children who have a diet based largely on crops grown in this way."

Actually, years ago as a child, I lived on the Elmstree Estate which is next door to Highgrove, and whose elm tree population was devastated by Dutch Elm Disease, a scourge of the British countryside in the late 1960s/early 1970s. We lived there in a rented part of the main farmhouse (which was the original manor house), since my family are hardly gentry, having fled South Wales where I was born, in the aftermath of my father's bankruptcy. Not such a big deal now but it certainly was then.

As plants grow they remove these essential elements to a varying degree and rainwater leaches out more, so from time to time they need to be replenished and so in conventional farming/gardening this is usually done by adding artificial fertilizers. In permaculture systems, plants die and rot-down and the nutrients are returned to the soil as part of the natural recycling process. The availability of nutrients and their uptake by plants is assisted by mycorrizal fungi which are found in the rootballs of most plants.

The three Major Nutrients are Nitrogen (N), Phosphorus (P) and Potassium (K). Nitrogen (N) is required for healthy stems and leaves. It is an essential component of the amino acids which form the proteins and of the chlorophyll molecules that harvest light to drive photosynthesis. It is normally taken up into plants in the form of Nitrate (NO3-) and to a lesser degree as Ammonium ions (NH4+). Nitrates are easily leached from soil by rainfall during the winter, but when spring comes and the soil warms, nitrogen is extracted from the air and converted to nitrate by nitrogen-fixing bacteria.

When the soil is waterlogged, denitrification occurs by anaerobic bacteria. This is why plants grow better in well drained soil where air can percolate through it. Earthworms play a vital role too, in burrowing through and processing soil, thus increasing the availability of its nutrients and creating drainage channels and spaces for root-systems to grow into.

Phosphorus (P) is taken up as phosphate ions (PO4(3-)), and is a critical component of the nucleic acids, DNA and RNA. The ATP-ADP energy transfer process within plant cells requires phosphorus. It is moved around within the plant, being recycled from older parts to points of new growth. The Carbon Dioxide released during respiration reacts with water to produce carbonic acid and this assists the uptake of PO4(3-) by plant roots. The secondary root-system provided by micorrizal fungi greatly extends the reach of the primary roots and more effectively remove the phosphate ions from the insoluble soil salts.

Potassium (K) is not an essential building block of plants but plays a central role in protein synthesis and in maintaining the balance of water. It also makes plants winter hardy and improves their resistance to disease. Taken up as K+ ions, the ratio of N to K has an important effect on plant growth, the ideal being N:K = 1 for most crops and 2:3 for root crops and legumes. Magnesium (Mg2+) ions compete with K+ for uptake, but so long as the K:Mg ratio is about 3:1 or 4:1 there is no problem.

The three Secondary Nutrients are:- Magnesium, as Mg2+ ions, is the key metal element in chlorophyll, where it forms the centre of the molecule and its light-absorbing process. It is involved in the production of the cellular energy-transfer molecule ATP.
Calcium in the form of Ca2+ ions is required for the healthy growth of new stems as it is used to give cell walls their strength. Sulphur (S) is taken up as sulphate ions (SO4(2-)), and is an essential constituent of all proteins, including enzymes. Legumes have higher requirements for S than most other plants do.

As the name implies, smaller amounts of the seven micronutrients are required but they nonetheless cannot be ignored for healthy plant growth, and are usually present sufficiently in most soils. These are boron (B) as H2BO3- ions, chlorine (Cl) as Cl- ions, copper (Cu) as Cu2+ ions, iron (Fe) as Fe2+ ions, manganese (Mn) in the form of Mn2+ ions, molybdenum (Mo) as molybdate (MoO4(2-)) ions and zinc (Zn) as Zn2+ ions.


Artificial fertilizers are manufactured using fossil fuels and have been responsible for massive increases in the yield of crops achieved in the last century - "The Green Revolution". There are estimates that the yield could fall by about 75% if we stopped using them. Accordingly, it is argued in some quarters that feeding the world's population without modern farming methods and its inputs of energy and fertilizers would require much more land than is available. Others, however, including many aficionados of permaculture dispute this, and argue that if the soil is brought back to its natural state there will be plenty of food for all, albeit not the cereal-based diet we are now used to.

Interestingly, there was a news report (B.B.C. March 5th) to the effect that most of us in the U.K. are deficient in selenium because for the past 30 years we have eaten bread made from European wheat rather than from wheat imported from Canada and the U.S. The problem is the different soil, which this side of the pond is low in selenium but rich in the element in North America and Canada. Apparently selenium levels can be restored to soil by adding selenium-enriched fertilizer, but this is part of the energy intensive process that we are seeking to avoid in preparation for declining oil and gas supplies. On a personal basis, eating a daily handful of Brazil nuts maintains healthy selenium levels but these are grown and imported of course by means of gas and oil, so this is not a long term solution.

If we convert to permaculture and regenerative agriculture in general, we will need to get by without much cereal and provide more of our diet from nuts, fruits and vegetables, and from animals whose grazing helps to till and nourish the land naturally on open-plains. Another good source of selenium is garlic, however, so long as it is not cooked for too long which denatures the compounds that contain it.

Related Reading.
http://www.dgsgardening.btinternet.co.uk/
http://www.permaculture.org.uk/mm.asp?mmfile=whatispermaculture
http://www.permaculture.org.uk/mm.asp?mmfile=whatproblem
http://www.foodnavigator.com/Science-Nutrition/New-trading-patterns-blamed-for-selenium-intake-decline