After driving all night from my North Georgia market gardens I arrived just before seven in the morning at the Indianapolis hotel where the ACRES U.S.A. Convention was to be held. The lines at the hotel desk were so long I left my colleague, Lorraine Cahill, to check in while I headed for the restaurant. I needed a steaming mug of coffee and a bite of breakfast to start my day. Otherwise I was in danger of fading away. Growing market veggies for 26 weeks for restaurants, markets and box subscribers had, thankfully, just come to a close before driving all night to reach America’s most unforgettable and inspiring convention. I didn’t want to miss a minute of it, but I had a booth to set up when the trade show opened and I needed more push than I had at the moment.

As fate would have it, as I joined the cue the people in front of me were Gary Zimmer from Wisconsin, Roelf Havinga from the Netherlands and a man named Rex (whose last name eludes my recall) from South Africa. We struck up conversation and all took a table together in the packed restaurant. I was the last one at my table through the buffet line, and as I took my seat I ventured that I figured the single highest priority we had as ecological farmers was to maximize the carbon we took out of the atmosphere and stored in the soil. After all, we, and all the things we grew on our farms, were carbon based life forms. “Funny you should mention that,” said Rex. “That’s precisely what I tell all my clients.”

Roelf echoed Rex’s sentiments with “You sure have got that right. When we store carbon in our soil we build life into our farms. I am all the time telling people this.”

The irrepressible Gary, who can say more in less time than all three Marx brothers talking at once, then regaled us with details of the whats, whys, hows, whos whens and the importance of catching carbon. “You can’t build soil without carbon, and the crazy thing about it is carbon is free. It’s the single most important thing a farmer can do. It’s a pity we cow farmers are demonized for releasing methane when growing grass and grazing it puts more carbon in the soil than anything else you can do.”

I had to agree with Gary that savvy graziers caught carbon more easily than any other type of farmer. The single biggest riddle I’d had to solve in self-sufficient biodynamic market gardening was how to build carbon into the soil whilst cultivation returned so much to the atmosphere. I’d discovered I had to maintain a grass and legume sod, almost as robust as my pastures, on all my traffic paths as well as growing robust mixes of the most productive crops I could find for my rotations. For those veggies like cukes, potatoes, capsicums, tomatoes, squash and ginger, mulch was the answer; but either way I had to keep the soil as fully covered as much of the time as I could, and I had to find ways of cultivation that minimized compaction and soil structure destruction.

After a delicious breakfast and lively discussion we got on with our day, each agreeing that being a good farmer meant catching carbon, first, foremost and always.

It should be no secret that excessive cultivation ranks right up there with mono-cropping and use of chemical nitrogen for driving carbon out of the soil and killing it; and yet, cultivation is what even the best organic and biodynamic market gardeners do. The trick is to not be excessive. Here is a picture of the method of cultivation I worked out. By cultivating metre wide beds between my tractor tyres and growing a mix of grass, clover and forbs on my driving strips I created heaps of edges—so beloved by observant permaculturists—whilst my paths were my biological reservoirs. There was never any spot in the field more than half a metre away from a rich diversity of plants and animals, small and not so small.

Maize or sweet corn, interplanted with soybeans, was my favourite way of catching carbon in summer. In winter it was cereal rye interplanted with a winter annual clover such as crimson clover, though I’m told arrowleaf clover or fenugreek are well suited to Australian conditions. In this mix I would also plant turnips, mustard greens, Chinese winter radishes and rape. Incidentally, corn salad, which used to grow in all winter grain paddocks, is an annual valerian that solubilises phosphorous and is known in German lore as rapunzel. The turnips, radishes and greens I harvested for market, as—like most folks—I needed a payday. The corn salad is a beloved and medicinal spring salad greens, and the grain can be cut for mulch at milk stage in the spring when it boots. Once the soil becomes crumbly and full of life, tomatoes, capsicums or cucurbits can be planted directly into the stubble with a spade—which is a pointed shovel—but don’t ever walk on the beds!

As for maize, the growing season is fairly long and earthworm populations would decline without mowing the paths for earthworm tucker about midway through the maize cycle. Earthworm populations need to be kept high in order to digest the thick stalks and soybean vines over winter after the rye is planted. Only the maize or sweet corn ears are picked, following the rule that if you want to build carbon you never export more than 8% of your biomass production. The spader pictured above has a beautiful tossing action that keeps the organic matter in the top two or three inches with just enough soil on top to plant the rye and clover mix into. The mass of maize stalks and soy vines need to be finely mowed before spading or the spader can’t chew them; but what a wealth of carbon is incorporated into the topsoil for moist, aerobic, fungal digestion! Fungal breakdown produces glomalin, which builds structural carbon into the soil.

Nitrogen management is another key. Loose, salty nitrogen burns carbon. It is the waste product of nitrogen fixing microbes, and when the soil is awash in it nitrogen fixers tend to feel like they are drowning in a dysfunctional septic tank. They say “That’s it. We’re out of here.”

What sets them on a nitrogen fixing jag is sugars. Then they produce amino acids that end up getting tied up with carbon in stable proteins in the soil reserve. On healthy soils that could easily be 3 or 4,000 ppm as stable protein nitrogen. Dumping something like raw chicken manure on the soil makes these beneficials give up the ghost and a protein breakdown cascade sets in. Then your soil loses carbon at a scary rate. Some estimate that 100 parts of carbon can be lost for every part of salt nitrogen added.

Also something else occurs—weeds. Unlike big seeds such as maize, beans and cereals, weed seeds generally are quite tiny. They depend on the soil being awash with soluble NPK and other nutrients. Their role in nature is to sop this up and conserve it. When it’s there they take off and outpace large seeded crops. Thus savvy farmers do not want much soluble nitrogen in the soil when they plant. They want nitrogen fixers to come running when large seeds start sprouting and excrete their carbs into the soil. Then there will be abundant amino acid nitrogen—all within a centimetre or so of the roots of the crop plants—while next to none will be available to the weeds even if they sprout. The picture just above shows maize with soybean at 21 days after planting.

Close inspection shows plenty of weeds which can’t get beyond the cotyledon stage because they don’t have any carbs to feed the nitrogen fixers, and they don’t have enough free nitrogen in the soil. This is an example of good nitrogen management in a vibrantly healthy living soil with plenty of nitrogen fixers living in it. And good nitrogen management is how to catch carbon and build it into the soil—even in a market garden.

To summarize, building soil carbon—the foremost imperative of every ecological grower—requires minimal, non-destructive cultivation. It also requires maximum diversity so the ecology is robust. It also requires good nitrogen management, which means keeping soluble nitrogen to a minimum and keeping plenty of nitrogen fixers alive in cultivated areas. This in turn means minimizing areas and times the soil is left bare. This also means NOT tilling in green matter which will decay and release soluble nitrogen.

And lest we forget, you want aerobic, fungal breakdown if you mix dry matter, like corn stalks, into the soil. This means you never incorporate organic matter deeply—even if it is dry—because you want fungi breakdown to make glomalin, build stable carbon and create superb soil structure.

Part I: Introduction

Employing the methods developed by P.A. Yeomans, keyline pattern plowing is a proven component in the job of revitalizing degraded soils. The plow performs deep ripping with minimal plant disturbance. At its most basic this offers many benefits, including opening compacted soils (without destructive tillage), breaking up the hard pan, allowing moisture and oxygen to re-activate soil life, thus restoring fertility.  When used in concert with controlled grazing or mowing through a managed cycle, top soil is built rapidly. 

In the related field of soil biology, Dr Elaine Ingham (the eminent biologist) has made breakthrough discoveries studying soil life and developing methods of brewing compost tea. Her work promotes the pressing need to re-populate our damaged soils with the necessary microbial biota. Without the essential micro organisms our soils cannot develop balance. A balanced soil offers fertility, that builds through the exchange for nutrients that is the tireless work of soil life. A multitude of symbiotic connections evolved in harmony.

With the generous support of the well respected compost tea educator and biological farming consultant, Paul Taylor (Trust Nature), I am developing a means to both inject compost tea into the root zone of pasture plants driectly, and perform a foliar (plant leaf) application while keyline plowing. The potential for this method to restore health and balance to soils is explosive.

I will therefore post a series of articles on taranakifarm.com detailing my development of this system so that others may be inspired to explore this exciting system (and perhaps make improvements).

Part II: Designing the Keyline Plow Frame Extension

Making Progress

I believe I’ve solved the tank (and equipment) frame extension question. The photos below mostly speak for themselves, although I’ll elaborate for the enthusiastic.

We made up a simple frame extension of welded steel box section that will form a platform for mounting the compost tea tank. In the photo below, you’ll notice I’m supporting the frame extension with timber, which obviously won’t do. So, next I’ll weld plate steel “L” brackets onto the extension where it meets the upper beam of the original keyline plow frame (positions A & B below). Then drill bolt holes so I can employ “L” shaped bolts. The same kind those used on the plow. I like standards and it makes everything multi-use, opening the door for more creative ideas.

Bolting onto the upper beam will support the extension, although it will not hold any significant weight. To solve this problem I will do the following.

Because the keyline frame is essentially a tool bar allowing great variation, it is essential to consider this variation when designing additions. To create a decent sized platform, my frame extension extends beyond the depth of the original frame, so it will require diagonal plate steel supports to bare weight. These will bolt to both the lower keyline beam and the new extension. This will give the extension support from below, as I intend to apply considerable weight to the platform above. As such I’ll need to make up at least two, maybe three supports.

A profile illustration of these supports is pictured left. To maintain a thin profile and not consume too much space on the rear keyline tool bar, I’ll most likely opt for plate steel. I must cut triangles out of each end of the plate piece to match the new frame extension and also the keyline plow. To sure this up, again, “L” constructs to bolt on.

These supports are then completely adjustable, which allows me to relocated the shanks and coulter beams without worrying about ‘permanent’ frame extension supports being in a fixed position. If they are in the way, I can just shift them, left for right. Total freedom. The general position is shown as dotted lines in the image below.

This extension also allows ample clearance beneath the tank platform should I need to access the shanks during plowing to change over a shear pin etc.

Part III: 1:1 Wooden Scale Model

Today I developed a 1:1 scale model of the platform supports. This allowed me to consider the design in more depth and get a feel for where the pressure points are. I constructed the model from cypress which obviously is much easier to work than box section or plate steel. I’ve established exact dimensions so constructing the steel version only involves cutting each ‘part’ of the assembly, then welding it together. All position issues, levels etc. are correct. No painful mistakes.

My only regret thus far, is employing non-standard box section steel for the frame extension. In the keyline plow, there are three sizes of box section employed. The main frame is constructed from 100×100mm RHS (Rolled Hollow Section). This is a very strong steel product. One that allows the frame to withstand extreme pressures during plowing. The coulter beams, which don’t experience the same stresses, are build from 75×75mm box section. Finally a smaller kind again is employed in the coulter assemblies themselves – the 50×50mm variety.

Since the frame extension was made up for a purpose other than its current application, I opted for 90×90mm. I briefly considered a ’sleeved’ design. Involving reversed coulter with a ’sleeve’ of 90×90mm over the 75×75mm. The intent – to create an extended rear platform. But the forces at play made me abandon it. If I had opted for 100×100, the platform supports would be fully reversible. A regrettable oversight.

For the supports, I’m using the same box section as the coulter beams. 75×75mm. Never to later to correct the course. I’m pleased with this design and look forward to creating the final steel versions.

Update

The steel brackets are now complete and working exactly as intended, with strength to spare. I anticipated a measure of ’spring’ based on the design, but this doesn’t seem evident. They are extremely robust, and very straightforward to construct.

One of the completed steel support brackets.

As it appears, mounted on the plow.

Read Parts IV to VI here

mycelium noun the white threadlike mass of filaments forming the vegetative part of a fungus

Whilst sounding tiny in both size and significance, it is not:

Is this the largest organism in the world? This 2,400-acre (9.7 km2) site in eastern Oregon had a contiguous growth of mycelium before logging roads cut through it. Estimated at 1,665 football fields in size and 2,200 years old, this one fungus has killed the forest above it several times over, and in so doing has built deeper soil layers that allow the growth of ever-larger stands of trees. Mushroom-forming forest fungi are unique in that their mycelial mats can achieve such massive proportions. – Paul Stamets, Mycelium Running

Watch the clip to learn more about these fascinating fungi – organisms totally ignored by industrial agriculture, but which are incredible allies as we seek to decontaminate and restore soils and other habitat.

Duration: 00:18:18

The latest research tells us that Peak Phosphorus is an issue we cannot afford to ignore any more:

… a global production peak of phosphate rock is estimated to occur around 2033. While this may seem in the distant future, there are currently no alternatives on the market today that could replace phosphate rock on any significant scale. New infrastructure and institutional arrangements required could take decades to develop.

While all the world’s farmers require access to phosphorus fertilisers, the major phosphate rock reserves are under the control of a small number of countries including China, Morocco and the US. China recently imposed a 135% export tariff on phosphate rock essentially preventing any from leaving the country. Reserves in the U.S. are calculated to be depleted within 30 years. Morocco currently occupies Western Sahara and its massive phosphate rock reserves, contrary to UN resolutions. – Western Sahara Resource Watch

Marcin, the podium is yours.

Keeping Phosphorus on Farms – by Marcin Gerwin (the sequel to ‘Closing the Phosphorus Cycle‘)

Lupines. Photo: Carol Mitchell/Flickr

“Next to clean water, phosphorus will be one the inexorable limits to human occupancy on this planet” wrote Bill Mollison in Permaculture: A Designers’ Manual more than 20 years ago (1). It is that important that we design phosphorus recycling into our food systems. Phosphorus is an essential element for growing crops and no porridge, chocolate bar or cherry jam can be made without it.

Mobilizing phosphorus present in the soil

In many soils phosphorus is naturally present in sufficient amounts, however, it may be chemically locked up and not available for plants. Most of agricultural soils in Western Europe and North America are oversupplied with huge amounts of superphosphate fertilizers, which results in binding phosphorus up with other elements so it ends up unused in the soil. In consequence, the concentration of phosphorus may be as high as 750 ppm, while only 45 ppm is necessary for growing grains (2). To determine whether you have a sufficient level of phosphorus in your soil, the surest way is to make a soil test. If the amount of phosphorus seems to be okay, but your plants show signs of phosphorus deficiency (purplish leaves, stunted stems), you may need help from a specially skilled team of phosphorus extractors – fungi. Fungi are decay experts in soils. The enzymes that they secrete allow them to break up lignin, cellulose, chitin shells of insects and bones of animals, which are too difficult to digest for bacteria. A single teaspoon of a healthy soil may contain several meters of fungal hyphae, invisible to the naked eye (3).

The tips of certain species of fungi have an extremely significant function. The strong acids they produce allow them to literally dissolve rocks and extract phosphorus from them. These fungi can form a mutually beneficial relationship with plants roots and can transport phosphorus to these plants. They are called mycorrhizal fungi.

Mycorrhizal fungi can extend the surface area of tree roots by 700 to 1000 times (4). They can harvest phosphates at great distances, many meters down and away from the plant and they bring it back through the fungal net, which is called plasmic streaming. Phosphorus is brought to a tree in exchange for sugars created by plants, as fungi don’t have the chlorophyll and the ability to photosynthesize.

Seedlings of trees, shrubs and perennials can be inoculated with mycorrhizal fungi while you grow them in the nursery. Make sure you get the right kind of fungal spores for your plants. You can inoculate roots of existing trees and shrubs by digging holes in a root zone and applying spores of mycorrhizal fungi near the roots. Seeds of annuals and vegetables can be mixed with inoculum as well, however, plants from the cabbage family (Brasicaceae), beets and spinach do not form mycorrhizal associations at all. Instead of buying inoculum in a shop, you can also experiment with making your own mycorrhizal inoculum.

The optimum range for phosphorus uptake by plants is pH 6.0 – 7.5, and on either side of the pH scale phosphorus becomes immobile. A conventional approach would be to adjust pH by adding sulfur in alkaline soils or lime in acidic soils. It can be quite expensive on a larger scale. But suppose you would like to grow an acid soil loving plant, such as Northern highbush blueberry, then what? The optimum pH range for this tasty fruit is as little as 3.5 – 4.8 pH, and it can fail completely when pH is higher. Since phosphorus is immobile at this low pH level, how can this plant grow at all? Well, it can receive phosphorus through partnerships with certain species of mycorrhizal fungi which do well in acid soils and don’t mind low pH when extracting phosphorus.

You could also try to adjust the pH by increasing fungal or bacterial domination in topsoil. You can apply brown organic mulches, such as woodchips and shredded branches, to support fungi and to lower the pH. Or, apply fresh green mulches and aerated compost teas to support bacterial growth and raise the pH slightly above 7. The reason for this is that bacterial slime is alkaline and acids secreted by fungi are, well, acidic and they lower soil pH.

However, some nutrients are available for plants in low pH, while others are available in high pH. The pH of soil should vary from micro-site to micro-site and it is the role of a healthy soil biology to control it. If we leave it to applications of lime or sulfur, the whole biological system will be temporally determined by this input, and the quantity of micro-sites of varying pH will be limited. So, instead of applying minerals in order to mobilize phosphorus by a chemical reaction, you could stimulate growth of a vigorous soil food web that will ensure extraction of essential elements and support their continuous recycling.

Choosing phosphate fertilizer

There are many soils around the world that are naturally deficient in phosphorus, such as soils in the Amazon Basin, on Java or in Australia. Others have been damaged by inappropriate farming practices – bare soils were flushed by rains, which washed away phosphorus, they were depleted by overharvesting of crops and their natural soil food webs were destroyed, making it impossible for plants to feed on anything other than artificial fertilizers. While soil food webs can be restored, wherever there is not enough elemental phosphorus present, for any reason, it must be brought back by the farmer. The other option is to wait until mountain-generating processes raise the bottom of the sea, where phosphate fertilizers end up. When the new mountain ranges are formed, the rain will start to wash phosphorus out of the rocks, making it available for plants again. But this will take some time – around 10-15 million years….

For organic gardeners one of the main sources of phosphorus are ground phosphate rocks. Good quality phosphate rock fertilizer should be free of all contaminants such as fluorides, heavy metals or radioactive uranium. It can be applied directly on soil (100 kg or more per hectare) tied to organic matter, mulch, compost and compost teas, to enhance soil biology and enable feeding plants through the activities of bacteria, fungi and other microorganisms. Another way is to incorporate rock phosphate into compost with a fungal dominance, so that fungi will transform rocks into a soluble form, or preparing a special phospho-compost (8). Inoculating plants with mycorrhizal fungi improves greatly effectiveness of phosphate rock fertilizers.

It has been discovered in Costa Rica, that phosphate fertilizers can be applied on top of the mulch, rather than below it. This idea has been conceived to prevent phosphorus from being bound up in the acid tropical soil. And it worked. Yields of beans rose more than 3 times (9).

Clay washed out from between layers of phosphate rocks during mining can also be used as a fertilizer. Particles of this clay are surrounded by natural phosphates and it’s called a colloidal phosphate. Thanks to clay the phosphorus is more easily available for plants than in phosphate rocks. It can be used together with manure on compost piles or directly on soil – manure acids will dissolve phosphates, which in turn will stabilize the nitrogen in manure (10).

Superphosphate fertilizers are made from chemically treated phosphate rocks. They are not recommended for use as they are highly concentrated and reactive. When applied on the field they react with calcium, iron, magnesium and aluminium, creating within seconds compounds that make phosphorus unavailable for plants. They may react also with trace elements, locking them up and causing deficiencies of micronutrients. Superphosphates are water soluble and they can be easily washed away by rains before plants have a chance to assimilate them, which later may cause the eutrophication of lakes and rivers. Not to mention that high concentrations of phosphorus in fertilizers (above 10) are lethal to mycorrhizal fungi (11). Superphosphates, however, do have their advantage: they were purified and do not contain toxic elements such as uranium. There is a disadvantage, though. The waste product of the purification process is stored in slag heaps, that are sometimes unprotected and, since they contain uranium, they are radioactive. Fluorides leaching from these heaps may also cause groundwater pollution.

Another material that is rich in phosphorus is guano – bird or bat droppings. Bones of fish that are eaten by seabirds contain a lot of phosphates, and as a result seabird guano also contains a high level of phosphorus. Guano has accumulated over centuries on small islands on the Pacific Ocean or on the coast of Chile and Peru, where it was mined in such large quantities that its deposits are now severely depleted. In contrary to phosphate rocks, it is a renewable resource, however, only over a long period. Apart from phosphorus, guano also contains high levels of nitrogen and calcium. It can be fresh, semi-fossilized or fossilized, depending on the source.

Phosphates can also be found in mud from ponds, in freshwater mussels, in fish waste, in algae or in recent volcanic ash. Many plants, such as comfrey, lupine, sweetclovers, nettle or vetches accumulate phosphorus and they can be used as green manure. Note, however, that they don’t produce phosphorus in the way that nitrogen is fixed from the air by legumes. Rather, they just extract phosphorus from one place and you can put it somewhere else, leaving the source with less phosphorus.

Building your own phosphate factory

Bat house on a tree Photo: Birdfreak.com

If you would like to collect phosphorus from your local area, the exciting way to do this is to establish a small bat colony. If there are bats living in your neighbourhood, especially in buildings, you can build a bat house for them. Bats will come to rest there and… they will leave their droppings underneath. You can place a container under the bat house and collect their guano. The additional benefit is that insectivorous bats consume large amounts of moths, mosquitoes, flies, grasshoppers and crickets among many others. They are high-class specialists in insect control – in just one hour a single brown bat can catch 1200 mosquitoes. In fact, they are so effective in eating mosquitoes that in India an establishment of bat colonies around Calcutta was considered as a way of dealing with excessive mosquitoes numbers (12).

If bats are not your kind of animal, you may consider another type of a phosphate factory – a pigeon house. Pigeons mostly eat seeds, and these are usually rich in phosphorus. Their manure is rich in nitrogen as well, so it could be very useful on farms, and some people in the Middle East still keep them. If you are wondering how the permaculture principle of "every element should serve many functions" could be applied with regards to pigeons, there is one interesting thing that some breeds of pigeons can do: they can carry letters. Harry Potter fans may feel a little disappointed and prefer owls for sending letters, but the advantage of pigeons is that they can do it for real.

The adapted ones

Proteoid roots of Acorn Banksia. Source: Annals of Botany

A small group of plants, which includes lupines and macadamia trees, has developed a unique strategy to adapt to phosphorus-deficient soils. Instead of forming mycorrhizal associations, they create densely clustered roots that enhance phosphorus uptake. These roots received a scientific name of proteoid roots, after the Proteaceae plant family. Despite their unimpressive name, proteoid roots of white lupine have an extraordinary ability: they excrete citrate and in this way increase availability of phosphorus in the root zone (13). Well, why not call them power roots instead? Or, phosphorus-I’m-coming-to-get-you roots? They deserve a better name.

The intriguing thing about proteoid roots is that plants do not form them when phosphate fertilizers are applied. To the surprise of a farmer,

Macadamia nuts on a tree Photo: Kahuroa

macadamia trees can show signs of phosphorus deficiency even though a significant amount of phosphate fertilizer was added. When phosphorus is present in soil, even in small quantities, these plants grow well by themselves. And, when there really isn’t enough phosphorus, then compost and mulch can be used, instead of phosphate fertilizers (14).

Protecting phosphorus from being washed away

Phosphorus loss occurs especially on bare, sandy soils, where you have little trees and get heavy rains. While natural systems such as forests can lose 0.1 kg of phosphorus per hectare per year, bare crop systems can lose even 100 kg of phosphorus per hectare in one year (15). In heavy soils or loams loss is generally very small. Most phosphorus in the environment is in the insoluble form and unlike nitrogen, which can be dissolved in water, it is washed away with soil particles or organic matter.

Lupines in New Zealand. Photo: Anita 363/Flickr

Soil eroded after storms carried to the sea by Betsiboka river in Madagascar. Photo: Earth Observatory

Since this is known, protecting phosphorus is easy. A good soil structure can be created by adding organic matter and compost. Soil biology can be further improved by brewing compost teas. Together with compost they will add an army of nutrient recyclers to the soil: active bacteria, fungi, flagellates, amoebas, ciliates and beneficial nematodes. These microorganisms will retain phosphorus in their bodies and the functioning of a whole healthy soil food web will allow recycling it. It is also worth mentioning that certain species of bacteria can also dissolve phosphate rocks and they help in converting phosphorus into forms that are edible for plants (16). A no-dig system can be introduced to prevent erosion and protect soil life, and trees can be planted on at least 30% of land. And it takes mulch, mulch and mulch to protect soil from rain.

Farmers can pull another ace out of their sleeves – charcoal! It is an ancient soil amendment, tried and tested for thousands of years by Indian tribes in the Amazon. They used it with pieces of pottery to create Terra Preta, the black soil, which is still fertile today, an exceptional thing in this region of the world. The porous structure of charcoal provides a great habitat for microbes, it persists in the soil for a very long time and it retains nutrients, including phosphorus (17). Charcoal (or biochar) can be made not only from wood, but also from agricultural residues, such as rice husks (18).

Roots of vetiver grass 6 months after planting. Photo: The Vetiver Network International

To slow down run-off in the mountainous areas, crops can be grown between rows of trees planted on contour, in an alley cropping system. These hedgerows can be planted with nitrogen-fixing trees, or other fast growing species. Prunings from the hedgerows can provide much needed mulch for crops.

Instead of trees, vetiver grass can also be planted on contour. Its roots grow 3-4 meters deep and it can reduce erosion by as much as 90% and recharge ground water (19). Over the years, on steep slopes, natural terraces will form behind the hedge, as soil will accumulate there. A vetiver grass system is easy to establish and requires little maintenance. It can also be used for stabilizing road embankments, river banks, preventing landslides and for wastewater purification.

Fair share

Some say that free market is the most efficient way of allocating scarce resources. This may be true. If you are a farmer from Europe then letting the invisible hand of the market allocate the remaining reserves of phosphate rocks could be no problem for you. Let the most competitive ones win! However, if you own half an acre of land somewhere in Sub-Saharan Africa, your soil is poor in nutrients, yields are low and you hardly make ends meet, then you can easily notice a simple thing – with free market rules, scarce resources don’t go to those who need them most. They go to those who can pay most.

In 2008 some 82 million people were added to our planet. The largest part of this population growth took place in the South: in Asia, Africa and in South America. All these young people, a population four times larger than the population of New York, will need food, water, clothes and a place to live. They will need land where crops will be grown for them. And to grow these crops many nutrients are essential. One of them is phosphorus. Since the reserves of phosphate rocks are scarce who will get it?

Bill Mollison again:

Of all the elements of critical importance to plants, phosphorus is the least commonly found, and sources are rarely available locally. Of all the phosphate fertilizers used, Europe and North America consume 75% (and get least return from this input because of overuse, over-irrigation, and poor soil economy). If we really wanted to reduce world famine, the redirection of these surplus phosphates to the poor soils of Africa and India (or any other food-deficient area), would do it. Forget about miracle plants; we need global ethics for all such essential resources (20).

Field of rice in Bihar, India. Photo: yumievriwan/Flickr

It is possible to calculate a fair share of the remaining phosphate rocks for each country, depending on the soil’s condition and number of population. And that’s exactly what should be done. A global agreement is necessary for sharing the last phosphate rock reserves in a common sense way.

Planting rice in Madagascar. Photo: Gail Johnson/Flickr

Our current industrial agricultural system and the global economy that supports it are inherently unsustainable. Extracting a limited resource, such as phosphorus, and sending it to landfills or dumping it in the ocean doesn’t make much sense. Sooner or later reserves of phosphate rocks will become depleted, then what? There is some back up in the form of deposits on the continental shelves and on seamounts in the Atlantic and Pacific Oceans (21), but the cost of mining it can be very high and even if industrial farmers were able to buy them, what about farmers from Botswana? What about farmers from Madagascar or India? What will be the cost of food, when the price of fertilizers goes up? Recycling phosphorus is just common sense and it seems inevitable, if we wish to continue living on Earth. It means that the exchange of our entire food supply and waste management systems is inevitable as well. Honorable presidents, distinguished prime ministers, sooner or later we will have to do it.

Why wait till the industrial food supply system collapses from lack of phosphate fertilizers or because they are too expensive to buy? Farming the way nature does provides not only healthy soils and good yields, but also nutritious food, flavoursome food. A juicy tomato with its characteristic, charming smell, instead of a watery, tasteless, red ’something’. Our economy can be more local, so that it will be possible to easily recycle nutrients, and as a result people will be more connected. These changes can be for better, not for worse.

If we manage to close the phosphorus cycle in our countries soon enough, we will have plenty of phosphate rocks left. We will be able to use them for restoring degraded lands, for planting trees, and greening our planet once again.

Acknowledgements:

A big thank you goes to Geoff Lawton who provided many of the ideas and practical solutions that are presented in this article. Geoff recorded his thoughts and comments while teaching abroad and he sent them to me as audio files. His insights are a backbone of this work.

References:

1. B. Mollison, Permaculture: A Designers’ Manual, 2004, p. 192.
2. Ibid
3. J. Lowenfells, W. Lewis, Teaming with Microbes, 2006, p. 53.
4. Ibid, p. 61.
5. Honglin Huanga, Shuzhen Zhanga, Xiao-quan Shana, Bao-Dong Chena, Yong-Guan Zhua and J. Nigel B. Bellb, Effect of arbuscular mycorrhizal fungus (Glomus caledonium) on the accumulation and metabolism of atrazine in maize (Zea mays L.) and atrazine dissipation in soil.
6. See also: K. Lewis, B. McCarthy, Nontarget tree mortality after tree-of-heaven (Ailanthus altissima) injection with imazapyr, Northern Journal of Applied Forestry, 25(2):66-72, 2008. In this study a herbicide imazapyr was injected to Tree-of-heaven (Ailanthus altissima), which in some regions is an invasive tree. The results showed that imazapyr injections not only killed all injected tree-of-heaven, but also 17.5% of neighboring (within 3 m) noninjected tree-of-heaven and eight other tree species 62 weeks after treatment. The possible ways of transmission of the herbicide were root grafts, mutually shared mycorrhizal fungi, root exudation and absorption, and/or leaf senescence.
7. Methodology: Integrated Production of Highbush Blueberry, edited by Danuta Krzewinska, 2005, p. 7.
8. See: chapter 9 “Ways of improving the agronomic effectiveness of phosphate rocks” in: F. Zapata and R.N. Roy, Use of Phosphate Rocks for Sustainable Agriculture, FAO 2004. Available at: http://www.fao.org/docrep/007/y5053e/y5053e00.htm#Contents
9. R. Bunch, Five Fertility Principles, The Overstory #20,
   http://www.agroforestry.net/overstory/overstory20.html, accessed on 16.01.2009.
10. P. Sullivan, Alternative Soil Amendments, ATTRA, http://attra.ncat.org/attra-pub/altsoilamend.html, accessed on 13.01.2009.
11. J. Lowenfells, W. Lewis, op. cit., p. 151.
12. Bats, The Ecologist,
    http://www.theecologist.org/pages/archive_detail.asp?content_id=352, accessed on 15.01.2009. In some parts of the world bats may carry viruses that are dangerous to humans. Before building a bat house in your backyard, please make sure there are no health concerns.
13. J. F. Johnson, D. L. Allan and C. P. Vance, Phosphorus Stress-Induced Proteoid Roots Show Altered Metabolism in Lupinus albus, Plant Physiology, Vol. 104, Issue 2, p. 657-665.
14. A. L. Shigo, Troubles in the Rhizosphere, The Overstory #70, http://www.agroforestry.net/overstory/overstory70.html, accessed on 13.01.2009. See also: G. Porter, R. Yost and M. Nagao, The Application Of Macadamia Nut Husk And Shell Mulch To Mature Macadamia Integrifolia To Improve Yields, Increase Nutrient Utilization, And Reduce Soil P Levels.
15. B. Mollison, op. cit.
16. R. Ivanova, D. Bojinova, K. Nedialkova, Rock Phosphate Solubilization by Soil Bacteria, Journal of the University of Chemical Technology and Metallurgy, 41, 3, 2006, 297-302.
17. Soil Fertility Management and Soil Biogeochemistry, Cornell University, http://www.css.cornell.edu/faculty/lehmann/research/biochar/biocharmain.html, accessed on 16.01.2009.
18. S. M. Haefele, Black Soil – Green Rice, Rice Today, April-June 2007, p. 26-27.
19. Soil erosion, The Vetiver Network International, http://www.vetiver.org/g/soil_erosion.htm, accessed on 16.01.2009.
20. B. Mollison, op. cit.
21. S. M. Jasinski, Phosphate Rock, Mineral Commodity Summaries, January 2008, p. 124,
    (available at: minerals.usgs.gov/minerals/pubs/commodity/phosphate_rock/).

It might sound ridiculous, but for every container of bananas, coffee, tea or cocoa imported, we should send back a shipment of a fluffy, earth-like smelling compost. Why is that? With each container of food we import nutrients taken up by plants from the soil. We import calcium, potassium, magnesium, boron, iron, zinc, molybdenum, copper and many others. One of the essential elements imported in food is phosphorus. For every ton of bananas we import 0.3 kg of phosphorus, for every ton of cocoa it’s 5 kg and for ton of coffee it’s 3.3 kg of phosphorus. Tea is a bit more complicated, because the amount of phosphorus depends on the origin of tea – for example in 1 ton of tea leaves harvested in Sri Lanka there are some 3.5 kg of phosphorus, while tea from South India contains 6.6 kg of phosphorus (1).

Each year some 13.5 million tons of bananas alone are exported around the world (2), containing 4,000,000 kg of elemental phosphorus up taken by the plants from tropical soils. And most of this phosphorus never comes back to the soil it was removed from. Yes, but can’t the farmers replace the nutrients lost using fertilizers? That’s what the fertilizers are used for, are they not? Sure they can. Farmers can buy a bag of ground phosphate rocks or guano (bird or bat droppings) or even a bag of artificial fertilizer such as superphosphate if they don’t farm organically. No problem. They can replace every kilogram of phosphorus taken from the soil by plants and sent overseas with their produce.

So, why should we send compost back on ships? This would add extra cost to the imported food and make it much more expensive! We should start closing nutrients cycle soon, because the world reserves of phosphate rocks, which are used for the production of phosphate fertilizers, are declining. They can be depleted even this century (3).

The problem with the lack of phosphate fertilizers does not start, however, when all phosphate rock reserves are gone. It starts as soon as the demand for phosphate fertilizers exceeds the supply of phosphate rocks available for export, meaning: farmers living in countries that do not have a local source of phosphate rocks would like to buy phosphate fertilizers, but there are not enough bags for everyone. And this situation may appear within the next 10-20 years.

This short timeframe is based upon the assumption that the demand for phosphate fertilizers will continue to grow and that within 10-20 years US reserves of phosphate rocks available for mining will be considerably depleted and USA will have to rely on imported phosphorus. It is unclear whether the phosphate exporting countries will be able to respond adequately to keep up with the rising demand by opening new mines or increasing production in the existing ones, which otherwise could lead to lack of sufficient amount of phosphate fertilizers on the market. A 50% rise in the US imports would require 50% rise of present world phosphate rock exports. A similar situation may exist in countries other than USA, but it was not taken into consideration due to lack of sufficient data. Demand for phosphate fertilizers in the USA may drop, however, owing to fall of agricultural production caused by droughts, depletion of water resources or by other climate related events. This could slow down domestic production of phosphate rocks and conserve these resources for a longer period of time.

What plants need Phosphorus for?

White sweetclover. Photo: Kristian Peters

Phosphorus is one of the key mineral nutrients that are necessary for plants growth. Phosphorus stimulates root growth, flowers blooming and seed development. It is an essential component of DNA, RNA, cell membranes, sugars and carbohydrates (4). Without phosphorus plants just don’t grow and there is no substitute for it. Although in many soils there are large reserves of phosphorus, it is often present in the form that cannot be used by plants (such as insoluble calcium or aluminum phosphate salts). Some plants, however, like white or yellow sweet clover for example (5), can mobilize phosphate by secreting organic acids (when harvested they can be used as a green manure with high phosphorus content), but far more efficient for this job are mycorrhizal fungi and microbes that secrete enzymes, various acids and chelating agents that turn organic and inorganic phosphate into a solution that can be taken up by plants (6). Nevertheless, when the content of phosphorus in the soil is low, all that farmer can do is to bring in some kind of phosphate fertilizer.

How much phosphate rocks is available for export?

Worldwide approximately 30 millions tons of phosphate rocks are exported every year, mainly from Africa (62.8% in 2006) (7). It sounds like a lot, but it is less than is needed for the consumption of a single country – the USA – the largest consumer, producer and supplier of phosphate fertilizers in the world. In 2006 the USA consumed 32.6 millions tons of phosphate rocks (8). Fortunately, USA is currently almost self-sufficient in production of phosphate rocks. In 2007 US imports accounted only for 2.8 millions ton of phosphate rocks (8.6%) and 99% of it came from just one origin – Morocco.

Phosphate rocks mine in Togo. Photo: Alexandra Pugachevskaya

However, the reserves of phosphate rocks in USA are limited. In 2007 there were only about 1,200 millions tons left (9). As soon as USA runs out of its phosphorus there will be a huge demand for the phosphate rocks. When might this happen? If the consumption in the USA continues to grow, the US domestic reserves could be gone in 25 years (10). At the current rate of production this could be in around 40 years. Most of the phosphate rocks in USA are mined in Florida and according to Stephen Jasinski from the U.S. Geological Survey “production in Florida could begin to drop in about 5 years or imports will be needed if the new mines are not opened (11).”

Demand for fertilizers is growing at the rate of 2.8% per year (12). It is expected to continue to grow, because fertilizers are needed to feed the increasing human population and to satisfy the need for biofuels. The acreage of industrial farms around the world which rely on artificial fertilizers may still increase in the years to come (e.g. in Russia, Brazil or even Madagascar) and in consequence the overall demand for phosphate fertilizers will rise. Certified organic farms can also use phosphate rocks (in unprocessed form), when phosphorus is deficient in the soil.

There are many countries like India, Australia, Poland and most of the Western European countries which are completely dependent on imports of phosphate rocks for fertilizing soils and growing food. And we import it mainly from Morocco as well. Without phosphate fertilizers yields of wheat, maize, tomatoes, strawberries, potatoes and many other crops will drop and eventually they could even fail. In Poland we have huge reserves of phosphate rocks. The problem is that the content of elemental phosphate in these rocks is low, they are located under villages, forests or farmlands or there is too much water in the mines to continue extraction.

However, if we manage to close the phosphorus cycle, there’s no need to worry about phosphate rock reserves. What we have mined so far can circulate from farm to table and back again, without depleting the soils. Let’s have a closer look where the phosphorus is leaking now.

Where does the phosphorus go?

In tropical climate phosphorus can be lost as soon as the farmer burns the rainforest to clear the site. Most tropical soils are poor in nutrients, and phosphorus is stored not in the soil, but in the vegetation. When rainforest is burnt phosphorus is left in the remaining ashes, but these ashes can be washed away by rains very quickly. There may be some old branches or unburnt leaves left on the ground and microbes can feed on them releasing phosphorus to the crops for some two years. But later on, when there are no more sources of phosphorus for the microbes to feed on and to release for plants, the land becomes infertile. And the farmer? If he cannot afford to buy commercial fertilizers he burns down another patch of the rainforest or he is forced to move to the city. There are more than 300 million slash-and-burn farmers worldwide, each one clearing about a hectare of forest a year (13).

On many farms, however, fertilizers are applied and farmers continue to grow crops. Some minimal amounts of phosphorus may leach from farm to groundwater, especially when artificial soluble fertilizer is used (such as superphosphate) (14). Most phosphorus losses occur through surface soil erosion, when soil is washed away by strong rain, or through harvesting of plants. Runoff of the nutrient rich water from the fields into the streams, lakes and oceans often causes explosion of the algae population and can lead to depletion of oxygen, seriously affecting aquatic animals and even coral reefs.

And what was the former one? Harvesting of plants? That’s right. With each apple, carrot, cucumber, coffee, cherry or watermelon a small bit of phosphorus is taken away from the soil. It can be eaten by the farmer and his family or loaded on truck and transported to the market. It can be also shipped overseas to the foreign supermarkets. So long nutrients! Have a good time in Italy or France! Please come back… one day.

Phosphate processing plant in Soda Springs, USA, operated byMonsanto. Source: The Center for Land Use Interpretation

Before food reaches the table many crops are processed and there are various residues left which contain phosphorus, e.g. orange peels or rice husks. They are either composted or sent to landfill. Then, finally, the consumer prepares a meal from the food that farmers harvested, and then leftovers with the precious phosphorus are thrown into the garbage or on the compost pile. The meal is eaten and out of the pizzas, spaghettis and apple pies only less than 1% of phosphorus is absorbed by our bodies (15) and remaining 99% is, in industrialized countries, flushed down the toilet. The content goes to a wastewater treatment plant. Treated biosolids from the treatment plants are reused as soil amendments or sent to the landfills. Part of the phosphorus from the wastewater treatment plant is discharged with treated water into the rivers or the sea.

Not all phosphate rocks are used for production of fertilizers. Around 5% are used as animal feed supplements and another 5% for industrial applications, e.g. for the manufacture of detergents. Some of us (like the author) are allergic to phosphates in soaps or washing powders and are a living proof that we do not need to use them at all. There are plenty of natural soaps and washing powders without phosphates we can buy or we can make our own.

Phosphate is used also for production of glyphosate, a herbicide which is known under a trade name Roundup. The manufacturer of Roundup, Monsanto, owns even a whole phosphate mine and rock processing plant in Idaho, USA. Luckily, organic gardeners don’t have to spray any of these. A much better idea would be to use the remaining phosphate rock reserves to restore degraded lands, rather than to produce herbicides or detergents.

Closing the nutrients cycle

Ideally the same amount of nutrients that left the farm should come back to it. To achieve this goal we should compost or ferment all residues from farms, food processing plants and households and make them available for farmers. And yes, we need to compost urine and feces as well. There are many types of compost toilets, including the simplest sawdust toilet to the commercial types with electric fans. If handled properly they don’t smell badly and the final product of the compost toilet is just a plain ordinary compost. It can be collected in the city in special containers, standing along the curb near the containers for recycling glass and plastics. Joseph Jenkins’ “Humanure Handbook” is a great resource on the subject.

All organic waste can be collected as a part of a municipality recycling program and leftovers from the kitchen can be picked up weekly from the separate curbside container. For backyard gardeners and farmers who eat their own food there are many methods of composting to choose from – buckets, triangle cages, compost tumblers, worm composting, loose heaps or classic wooden containers. There are even composters which can be kept directly in the kitchen without any suspicious smells.

It seems also a good idea to extract carbon and hydrogen from the food residues in the form of biogas which is primarily methane (CH4). It can be used for cooking, heating, electricity generation or for powering vehicles. The exciting thing about biogas is that we don’t waste any of the minerals from the organic matter – carbon is taken by plants from the air in the form of carbon dioxide and hydrogen comes from water. After fermentation process in a biodigester the organic matter is still perfectly useful as a fertilizer.

If the resources of phosphate rocks become depleted this organic waste recycling program will be crucial for farmers. They will be able to buy or receive finished compost according to the amount of food they sold. It may sound absurd, but the content of phosphorus or other nutrients in crops may eventually be counted in the future, so that we can determine how much compost the farmer should receive. Ideally local food should be involved in this scheme to minimize transport needs. And what about the food from overseas farms like coffee or tea? Well, things get much more complicated here. Theoretically, we could exchange nutrients in the form of food, so that for every kilogram of coffee would send back wheat or barley with the equal content of phosphorus. What farmers can do now is to bring compost from the cities, where people eat imported food. The other option is sending compost back. Hmm… Wouldn’t it be just perfect to have a village scale economy where all nutrients would circulate without cars, trucks, cargo ships and complex municipality programs?

Growing food security

Trees in bloom in the Hunza Valley. Photo: bongo vongo

In places like the Hunza Valley (currently northern Pakistan) and many others around the world, people have grown food in one place for hundreds of years without depleting the soil. As Rob Hopkins writes in his Transition Handbook about the Hunza Valley:

Here was a society which lived within its limits and had evolved a dazzlingly sophisticated yet simple way of doing so. All the waste, including human waste, was carefully composted and returned to the land. The terraces which had been built into the mountainsides over centuries were irrigated through a network of channels that brought mineral-rich water from the glacier above down to the fields with astonishing precision.

Apricot trees were everywhere, as well as cherry, apple, almond and other fruit and nut trees. Around and beneath the trees grew potatoes, barley, wheat and other vegetables. The fields were orderly but not regimented. Plants grew in small blocks, rather than in huge monocultures. Being on the side of a mountain, I invariably had to walk up and down hills a great deal, and soon began to feel some of the fitness for which the people of Hunza are famed. The paths were lined with dry stone walls, and were designed for people and animals, not for cars.

People always seemed to have time to stop and talk to each other and spend time with the children who ran barefoot and dusty through the fields. Apricots were harvested and spread out to dry on the rooftops of the houses, a dazzling sight in the bright mountain sun. Buildings were built from locally-made mud bricks, warm in the winter and cool in the summer. And there was always the majestic splendour of the mountains towering above. Hunza is quite simply the most beautiful, tranquil, happy and abundant place I have ever visited, before or since (16).

Rakaposhi mountain near the town of Gilgit, Hunza Valley. Photo: bongo vongo

Villages can provide a good life and it is easy to design a local food system that ensures food security there. Food security means that all people have access to safe, nutritious and affordable food, at all times, without degrading the supporting systems (17). No matter if your food comes from the grocery store or the backyard garden, it contains some amount of nutrients it has taken up from the soil where it was grown. If we wish to sustain fertility of our soils, and thus food security, we need to return these nutrients to the soil, so that our tomatoes, corn and apple trees will be able to grow and produce crops forever.

In a natural environment this nutrients cycle is supported by a myriad tiny creatures. There are bacteria and fungi in the soil that hold the nutrients and extract them from rocks or the air. There are nematodes, protozoa, arthropods and earthworms that cycle these nutrients and make them available for plants (18). We, humans, are also a part of the soil food web. Our job is to return the wastes to the soil. We can design our farms so that they will work just like natural systems, cycling the nutrients over and over again. A good example of such a system in an old growth forest. It doesn’t need fertilizing, weeding or irrigating. It grows by itself and it is always productive. That’s a clever system, isn’t it?

Beach in Sopot, Poland. Photo: Marcin Gerwin

We can design for food security in cities as well, but it’s not as easy as in villages. Most people living in the cities buy food rather than grow it on their own, so the whole economic system must be working properly, so that they will be able to afford it. The food shortages in 2008 around the world were not caused by a lack of food, but because people didn’t have money to buy it. The first thing to do would be to start growing food right in the city. On vacant parking lots, on roofs, in backyards. But what if there is not enough space? I live in a small city on the coast of the Baltic sea. Sopot is a summer resort bordered by the sea, a landscape park and two large cities. The land here is among the most expensive in Poland. There is no way one could buy a vacant lot for a vegetable garden, it would cost a fortune. We do have many allotments, but there’s not enough for everyone. So, what can we do?

Wooden pier in Sopot. Photo: Marcin Gerwin

Right now access to food is not a problem. It is available in every grocery store and in all supermarkets. It’s not an issue. With peak-oil or unexpected weather events this could change. With the lack of phosphate fertilizers it could change as well. A large portion of food in Poland is grown in the conventional way and farmers apply artificial fertilizers and spray pesticides. Some of them believe that plants without fertilizers don’t grow, so I think it may be a little hard to try to convince them to use compost instead of the factory-made fertilizers.

I also find it hard to believe that everyone in Sopot could easily accept compost toilets. We would have to recover nutrients from the treatment plant, which is located… er… I must admit I don’t know where our sewage goes to. We will have to collect organic waste, however, that’s what the European Union regulations will make us to do in the years to come (you see, there are some positive aspects of our county being an EU member). We could also start a co-operation program with the farmers from the area, who could supply food directly to our city, rather than through distributors. We could have long-term contracts with them, just like in the Fairtrade scheme. We could set a guaranteed minimum price for farmers, so that their security would improve as well. And what if the economic system collapses? Then we need a land reform.

Continue to: Phosphorus Matters II – Keeping Phosphorus on Farms

References:

(1) Phosphorus content in food based upon: Organic Farming in the Tropics and Subtropics: Exemplary Description of 20 Crops, Naturland, second edition 2001.

(2) Calculated from: Banana facts, IITA Research for Development Review, http://r4dreview.org/2008/09/banana-facts/, accessed on 14.09.2008.

(3) D. Cordell, S. White, The Australian Story of Phosphorus, 2008, p. 1.

(4) S. B. Carrol, S. D. Salt, Ecology for Gardeners, 2004, p. 149.

(5) Sweetclovers, UC SAREP, Online Cover Crop Database, http://www.sarep.ucdavis.edu/cgi-bin/ccrop.EXE/show_crop_41, accessed on 15.09.2008.

(6) Ibidem, p. 116 – 117.

(7) Production and International Trade Statistics, International Fertilizer Industry Association (IFA), http://www.fertilizer.org/ifa/statistics/pit_public/pit_public_statistics.asp, accessed 14.09.2008.

(8) S. M. Jasinski, Phosphate Rock, Mineral Commodity Summaries, January 2008, p. 124, (available at: minerals.usgs.gov/minerals/pubs/commodity/phosphate_rock/).

(9) Ibidem.

(10) D. Cordell, S. White, op. cit.

(11) S. Jasinski, Phosphate Rock (Advance Release), 2007 Minerals Yearbook, p. 56.3.

(12) P. Heffer and M. Prud’homme, Summary Report “Medium-Term Outlook for Global Fertilizer Demand, Supply and Trade: 2008-2012”, 76th IFA Annual Conference, Vienna, May 2008, p. 4.

(13) D. Elkan, The Rainforest Saver, The Ecologist Magazine, 01.02.2005, http://www.theecologist.co.uk/pages/archive_detail.asp?content_id=424.

(14) S. B. Carrol, S. D. Salt, op. cit., 117.

(15) T. N. Neset, L. Andersson, Environmental impact of food production and consumption, in: Water for Food, 2008, p. 102.

(16) R. Hopkins, The Transition Handbook, 2008, from the introduction.

(17) For more information on food security watch presentation given by Bruce Darrel: Converging Crises, Policy Responses: Planning For Food Security, Festa Seminar Series, June 19th, 2008. http://www.feasta-multimedia.org/2008/seminars/Bruce_Darrell.mov

(18) The soil food web is described in detail in the excellent book Teaming with Microbes by Jeff Lowenfells and Wayne Lewis.

Soil – the substance you walk on, build on, and live from – provides your food, clothing, and even the air you breathe. It gives warmth, shelter, and the goods you possess. Soil is, I believe, a substance that is under-acknowledged, and also under attack, and its misuse is contributing greatly to the excessive release of CO2 into our atmosphere – making it a large contributor to global warming. Therefore, I felt it high time we came to its defense. Here goes.

Firstly, what is soil? Unfortunately, and increasingly, the modern mindset simply regards it as ‘dirt’ – something to clean off your nine-year old son’s knees if he’s fallen out of that tree, or worse, at an industry level, its regarded as nothing more than an inert medium for sowing plants – just somewhere to put them. For agri-businessmen, little or no connection is made between the health of the soil, and the health of the plants they produce. The mechanised treatment of the soil is arbitrary and aggressive, and the consequences of this disconnect are dire.

More Than Just Dirt! There are over four billion micro-organisms in a teaspoon of healthy soil

You could simplify its composition by reducing it to four main components: minerals, air, water, and organic matter. The complicated version, however, is almost beyond belief, and despite the best efforts of scientists many aspects remain mysterious.

Hidden from immediate notice, a healthy soil contains innumerable micro and macro-organisms. In fact (and I haven’t counted these personally) there are said to be over four billion micro-organisms in just one teaspoon of healthy soil. If you were to add the combined weight of all the living micro-organisms in an average acre of land, they’d weigh about as much as a typical domestic cow. These organisms work with each other, and with plants, in a symbiotic relationship that ultimately provides for the needs of all creatures that walk, fly, or swim on our planet. Part of their work is to break down decaying organic matter, along with minerals in the soil, and then make these available to plant roots in a nutrient form they can utilise. They are essentially an immense army of recyclers – working for our benefit without reward and with scant recognition.

This natural process of micro-organisms feeding plants is significant, and highly complex. Through the work of these creatures a plant receives what we might call a ‘balanced diet’. To illustrate: What do you think a small boy would do if you gave him an enormous bar of chocolate to eat? Chances are good he’d keep eating it until it made him sick (even if half of it is still left on his face!). Children are unable to gauge an appropriate quantity, and will quickly scoff all they can fit in. The result? Even if he doesn’t make himself ill, your child goes on a physical and emotional roller-coaster ride until the refined sugar-induced energy dissipates. A wise parent might instead supply an appropriately sized portion of ’sugar’ in its natural state – bound up with fibrous dry matter in the form of whole fruit.

Modern agri-businesses do similar with their water-soluble fertilisers – they set a ‘meal’ before the plant that can be immediately absorbed by plant roots, essentially by-passing the balanced slow-release feeding by micro-organisms. Just like a child, this affects a plant’s health.

For example:

Pesticide residues are not the only problem arising from modern agricultural techniques. Increasingly, nitrate levels in vegetables are causing concern, although most attention so far has been focused on nitrates in water supplies…. About 70% of average daily nitrate intake comes from vegetables, compared with only 20% from drinking water. Nitrates are taken up very readily by crops, and if they are not utilised immediately in the formation of protein, they are stored in the cells in their original form. There is then the risk that when nitrates are ingested or cooked, they convert to nitrites which can potentially combine with amines to form carcinogenic nitrosamines. – Organic Farming, Nicholas Lampkin p.565.

Additionally, in the insect and plant world the weak are attacked first, just like lions and antelope on the savanna! Plants grown in a healthy soil using sustainable methods are consistently shown to be resistant to attack from insects and diseases.

Our newsletters have often explained how mycorrhizal fungi attach to plant roots and bring great amounts of needed nutrients to the plant, functioning like millions of extra feeder roots. These well-nourished plants become more disease resistant and produce higher yields or more flowers.

A less obvious benefit is reduced insect attacks. In our grow testing, we can often tell the mycorrhizal plants from control plants from some distance away, not just by size but also by a difference in leaf damage.

This same sort of difference can be seen by comparing plants fertilized with slow-release fertilizer versus those given fast-acting forms, especially liquids. The quick greening and rapid burst of growth that you get after drenching plants with liquid fertilizer is obviously an invitation to harmful bugs.

So what’s going on? There are different theories about this subject, but one is that certain insects are programmed by nature to eliminate sick or otherwise imperfect plants. When you create unnaturally lush growth on a plant, something about those leaves seems to be like a neon sign that triggers the “must destroy” instinct in bugs, even though the plant may look normal to our eyes.

Another theory is that completely healthy plants produce a substance that tastes bitter to insects – sort of a natural repellant – but a plant that is pushed with fast NPK fertilizer apparently does not form those anti-bug substances and tastes delicious.

Whatever the reason, the way to grow plants that won’t require drenchings of toxic rescue chemicals is to use small amounts of slow-release nutrients that are delivered as-needed to the roots by biological action. The use of any high-analysis fertilizer, especially in liquid form, seems to be a major cause of insect attacks.

Of course, the nice companies that so heavily promote their wonder fertilizers are also happy to sell you bug sprays later. But I’m sure they don’t realize that their plant food is creating the need for insect protection. Real sure. – BioOrganics

The soil, if allowed, will absorb more CO2 than it gives out

Another significant, and highly relevant, role of soil micro-organisms, is carbon sequestration (storage):

The estimated amount of carbon stored in world soils is about 1,100 to 1,600 petagrams (one petagram is one billion metric tons), more than twice the carbon in living vegetation (560 petagrams) or in the atmosphere (750 petagrams). Hence, even relatively small changes in soil carbon storage per unit area could have a significant impact on the global carbon balance.

Carbon sequestration in soils occurs through plant production. Plants convert carbon dioxide into tissue through photosynthesis. After the plants die, plant material is decomposed, primarily by soil microorganisms, and much of the carbon in the plant material is eventually released through respiration back to the atmosphere as carbon dioxide.

But some of it remains when organic materials decay and leave behind organic residues, often called humus. These residues can persist in soils for hundreds or even thousands of years. – Geotimes

Given all the attention and commotion over global warming today, this ability of our soil to naturally assimilate CO2 on a grand scale should be examined far more than it is. This ‘humus’, mentioned above, is the dark black content of a healthy soil – black due to the carbon content itself. Humus could best be described as the final result of decaying organic matter. It is a stable substance – slow to accumulate, and slow to deplete – and is critical for the soil’s biological activity. This stable state is in stark contrast to our industrial fertilisers, which, in addition to over-absorption by plants, also contaminate streams and rivers and leach into our water table.

Subsequent decomposition of dead material and modified organic matter results in the formation of more complex organic matter, called humus. This process is called humification. Humus consists of a group of humic substances that includes humic acids, fulvic acids, hymatomelanic acids and humins and is probably the most widely distributed organic carbon-containing material in terrestrial and aquatic environments….

Humic substances enhance plant growth directly through physiological and nutritional effects. Thus humic acid is capable of improving seed germination, root initiation and uptake of plant nutrients, and serves as a source of nitrogen, phosphorus and sulphur. Indirectly, they may affect plant growth through modifications of physical, chemical and biological properties of the soil, such as an increase in water holding capacity and cation exchange capacity, and improvement of tilth and aeration through good soil structure. – FAO

Humus is a rich resource – and could easily be compared to a modern day bank. Deposits and subtractions are made by the natural rhythm of decay and recycling through the weathering of air, water, and complicated interactions of various types of soil macro and micro-organisms. This ‘bank’ has been our central ‘financial institution’, sustaining our race for millennia, although there have been times in our history, in localised areas, where subtractions have exceeded deposits – resulting in biological bankruptcy.

Throughout history, the story has repeated itself: Great civilizations have grown where soils were fertile enough to support high-density human communities, and fallen when soils could no longer sustain our rough treatment. According to the International Task Force on Land Degradation, the great early civilizations of Mesopotamia arose because of the richness of their soils, and collapsed because of declines in soil quality. Poor land management and excessive irrigation caused soils to become increasingly degraded, leading to power struggles, migrations, and ultimately, the collapse of the Fertile Crescent civilizations.

Ancient Greece suffered a similar fate. The philosopher Plato, writing around 360 B.C., attributed the demise of Greek power to land degradation: “[In earlier days] Attica yielded far more abundant produce. In comparison of what then was, there are remaining only the bones of the wasted body; all the richer and softer parts of the soil having fallen away, and the mere skeleton of the land being left.”

Many experts also blame the collapse of the great Mayan civilization and the peaceful Harappan society of the Indus valley on soil exhaustion and erosion, resulting from agricultural practices and clear-cutting of forests. According to Jared Diamond, a UCLA professor and author of the books Guns, Germs and Steel and Collapse, 90 percent of the people inhabiting Easter Island in the Pacific died because of deforestation, erosion and soil depletion. In Iceland, farming and human activities caused about 50 percent of the soil to end up in the sea, explains Diamond. “Icelandic society survived only through a drastically lower standard of living,” he says. – The Scoop on Dirt, Tamsyn Jones

Since the use of the plough, then the tractor, and especially since WWII military chemical companies found a post-war use for their chemicals (pesticides, then fertilisers), the organic content of our soils, and consequently soil and plant health, has been in serious decline. This has resulted in even more fertilisers being applied to boost productivity, and the resulting poor health of plants subsequently encouraging the use of even more pesticides.

Costly petroleum-based fertilisers have long been touted as the solution to the world’s problems of poverty and hunger by the industries that produce them, but their use has not only necessitated pesticide application, but also encouraged a complete disregard of the free, and healthful, systems of fertilisation that are already available to us. This food-in-a-test-tube mentality is forgetting a significant fact – even putting plant health and water purity aside, this kind of agribusiness is wholly finite. As a soil’s inherent fertility is squandered the soil loses its structure. These lifeless soils become increasingly difficult to use, even as an ‘inert medium for placing plants’. The term ‘increasingly difficult’ translating to more expensive and energy intensive (i.e. increased mechanised interventions). Ultimately these lifeless soils are discarded and become what we call ‘marginal lands’ or ’set-asides’, forcing increased output on that which remains – or increased deforestation, so we can gorge ourselves on fresh virgin soil.

To our shame, the rich black soils that were commonplace in America when the Mayflower landed, the natural accumulation of centuries of natural processes, are now largely a thing of the past. Besides issues of plant and human health, water contamination and loss, soil compaction, erosion and desertification – this has also meant the carbon absorption ability of the soil has decreased significantly. Great quantities of CO2 that should be stored in the humus content of healthy soils have been systematically released into the atmosphere.

Much of the world is suffering from degraded soil fertility

- During the past 40 years nearly one-third of the world’s cropland (1.5 billion hectares) has been abandoned because of soil erosion and degradation.

- About 2 million hectares of rainfed and irrigated agricultural lands are lost to production every year due to severe land degradation, among other factors.

- It takes approximately 500 years to replace 25 millimeters (1 inch) of topsoil lost to erosion. The minimal soil depth for agricultural production is 150 millimeters. From this perspective, productive fertile soil is a nonrenewable, endangered ecosystem. – The Global Education Project

A Cornell University scientist says soil around the world is being swept and washed away 10 to 40 times faster than it’s being replenished.

Professor of Ecology David Pimentel says cropland the size of Indiana is lost each year, yet the Earth’s need for food and other grown products continues to soar.

“Soil erosion is second only to population growth as the biggest environmental problem the world faces,” said Pimentel. “Yet, the problem, which is growing ever more critical, is being ignored because who gets excited about dirt?”

Pimentel said 99.7 percent of human food comes from cropland, which is shrinking by nearly 37,000 square miles each year due to soil erosion, while more than 3.7 billion people are malnourished.

The study, which pulls together statistics on soil erosion from more than 125 sources, notes the United States is losing soil 10 times faster — and China and India are losing soil 30 to 40 times faster — than the natural replenishment rate.

Damage from soil erosion worldwide is estimated to be $400 billion per year. – Physorg.com

Thankfully, we also have historical record of peoples that have managed to not only survive on the same pieces of land, but prosper, even with highly populated, intensive agricultural production. One well-known reference book on this subject is Farmers of Forty Centuries (now available as a freely downloadable ebook ), documenting four thousand years of successful sustainable management by Chinese, Japanese and Koreans. The systems of these past agriculturally-sustainable nations have, despite their not having microscopes or beaker tubes, maintained (or indeed, improved) the soil over the course of many centuries – and despite operating an almost completely ‘closed system’, i.e. without importing fertilisers, let alone pesticides, etc., which we today use in huge amounts, and which are produced at high financial and environmental cost from finite fossil fuel sources.

We’ve ascertained that a healthy soil is one that is abundant in soil life, but how do we increase and maintain this fertility? Well, our macro and microscopic friends have just a few simple needs – needs that are actually very similar to our own.

• air
• water
• energy

Channels created by plant roots and the very porous texture of a humus-rich soil, provide the right amount of air for balanced microbial activity. I say ‘balanced’, because you can have too much of a good thing. Over aeration of the soil through ploughing and tilling (if it doesn’t bury the organisms to a depth where they cannot function and are destroyed entirely) can cause excess activity (or, to use a modern phrase – hyperactivity), hastening the breakdown of organic matter and humus. Using our financial analogy, it’s like blowing a month’s wages in a week. This is often followed by a complete lack of oxygen with which to work – as the reduced soil texture, combined with compaction from heavy equipment, creates anaerobic conditions that destroy soil life and encourage disease.

A healthy soil, rich in organic matter, holds, filters and purifies downwardly mobile water, and also allows the upward movement of water through capilliary action. Even sandy soils, which generally leach both water and nutrients very fast, can hold considerable amounts of moisture if it has a high organic content. Heavy soils, those high in clay, often hold too much water (especially after the compacting effects of tractors, etc.) due to very fine-grain structure and water-binding nature of clay particles. Overdosing in water essentially drowns micro-organisms, as it robs them of the oxygen they need to survive. These heavy soils also benefit greatly from a high humus content, as it again encourages the porous texture that allows for the free flow of water (and air) needed for healthy microbial action. This texture is also essential in heavy soils or plant roots cannot penetrate.

Energy comes through the presence of organic matter itself – something almost always removed (or buried out of reach of micro-organisms) in the modern ’sterile’ system of agriculture.

The question of how to restore and maintain soil fertility is best asked of nature herself. What would happen to the world if, today, we all just got up and left – if we had the means and ability to head off to a fresh new planet where we could just start all over? Now, I’m not asking you all to leave – hey, I like you guys – but what would be the result back down here on terra firma? What, in particular, would happen to our soil in that huge percentage of inhabitable land that we are currently using intensively for agricultural purposes?

Give the worms a fighting chance! Modern farms are increasingly devoid of worms – but these guys (somehow) mysteriously eat and excrete soil, making it more nutrient-rich than when they started. May our farmers re-learn how to do the same! (figuratively speaking…)

Those fields that have been ploughed and turned and churned would, with relief I dare say, surrender to the restorative influence of an amazing natural process. Firstly, in our absence, plants that are specifically able to grow in each condition (some like to call them ‘weeds’) would spring up to do what nature always seeks to do with soil – cover it up! This protective covering prevents erosion and loss from wind and rain (a good topsoil is slow in the making – so erosion is like a bank-robbery). Next, this thin initial film of ground cover would, through photosynthesis and root action, slowly, in an almost self-sacrificial manner, develop an improved state – in doing so rendering itself redundant and promoting the growth of a new phase of plants, which in turn would improve the soil further, and so on. The inevitable cycle of life, photosynthesis, root action, death, decay and recycling (including the addition of animal ‘by products’) would ultimately restore a healthy structure (tilth) and bring our exhausted soils back to verdure. It’s a hard thing to say – but we’re just plain not needed, and are usually positively damaging!

Of course, as much as we’d like to stop the earth and get off, we cannot just head off to another planet (indeed – we shouldn’t be allowed if we haven’t figured out how to look after this one). The good news is if we can imitate nature’s practices as closely as possible, and incorporate these into our farming methods, we can reverse the unsustainable pressures we’re currently placing on our land.

Working with living creatures, both plant and animal, is what makes agriculture different from any other production enterprise. Even though a product is produced, in farming the process is anything but industrial. It is biological. We are dealing with a vital, living system rather than an inert manufacturing process. The skills required to manage a biological system are similar to those of the conductor of an orchestra. The musicians are all very good at what they do individually. The role of the conductor is not to play each instrument but rather to nurture the union of the disparate parts. The conductor coordinates each musician’s effort with those of all the others and combines them in a harmonious whole.

Agriculture cannot be an industrial process any more than music can be. It must be understood differently from stamping this metal into shape or mixing these chemicals and reagents to create that compound. The major workers – the soil microorganisms, the fungi, the mineral particles, the sun, the air, the water – are all parts of a system, and it is not just the employment of any one of them but the coordination of the whole that achieves success. – Eliot Coleman, The New Organic Grower, p.3, 4.

Sustainable farming can be described as “one that meets the needs of the present without compromising the ability of future generations to meet their own needs”. Such a statement would automatically lead one to think wistfully about the needs of future generations. But, we need to realise we are the future generation. We are, today, the people that have to deal with depleted, humus-reduced (which translates to carbon-reduced), unproductive soils that have been handed down to us from decades of plundering. Over the past several decades people have made themselves rich, withdrawing from the financial institution that is our soil – and never giving back. We are facing biological bankruptcy, and, despite the good intentions of many energetic promoters of organic farmers, our world is so specialised and distanced from nature that our politicians seek to not only continue these subtractions, but substantially increase the burden already placed on our soils.

The word irresponsible is defined as “not having or showing any care for the consequences of personal actions”. Modern large-scale industrial agriculture is exactly that. We need to turn it around.

In order to understand our own time and predicament and the work that is to be done, we would do well to shift the terms and say that we are divided between exploitation and nurture….

Let me outline as briefly as I can what seem to me the characteristics of these opposite kinds of mind. I conceive a strip-miner to be a model exploiter, and as a model nurturer I take the old-fashioned idea or ideal of a farmer. The exploiter is a specialist, an expert; the nurturer is not. The standard of the exploiter is efficiency; the standard of the nurturer is care. The exploiter’s goal is money, profit; the nurturer’s goal is health – his land’s health, his own, his family’s, his community’s, his country’s. Whereas the exploiter asks of a piece of land only how much and how quickly it can be made to produce, the nurturer asks a question that is much more complex and difficult: What is its carrying capacity? (That is: How much can be taken from it without diminishing it? What can it produce dependably for an indefinite time?) The exploiter wishes to earn as much as possible by as little work as possible; the nurturer expects, certainly, to have a decent living from his work, but his characteristic wish is to work as well as possible. The competence of the exploiter is in organization; that of the nurturer is in order – a human order, that is, that accommodates itself both to other order and to mystery. The exploiter typically serves an institution or organization; the nurturer serves land, household, community, place. The exploiter thinks in terms of numbers, quantities, “hard facts”; the nurturer in terms of character, condition, quality, kind. – Wendell Berry, The Agricultural Crisis a Crisis of Culture, p. 13, 14.

Exchange our current large-scale monocultures with smaller more diverse systems that include crop rotations , green manures , leys, composting and animal wastes, and we may yet regain that which we’ve lost. The laws of nature are a powerful force. We do not have the power to alter them, even though some would try, nor can you break them without consequence. Work in harmony with nature, however, and we will get back not just our soil fertility, but also health of body and character, and our relationship with the land.

Civilisations have come and gone, disintegrating, relocating and learning hard lessons about soil-abuse. Relocating is not an option anymore. We cannot wait for the 20/20 vision of hindsight – as there are no more frontiers. Continuing on this agricultural trajectory will see wealthy countries collapse – although not before turning to plunder the soil and water reserves of weaker nations.

In the last century the global population has exploded from two billion people to over six and a half billion today. Our society must learn, or collapse. It’s as simple as that.