Replenish the soil

On this page..

  1. Soil, an incredible new science!
  2. Water solutions
  3. Phosphorus solutions
  4. The ultimate soil amendment — biochar!
  5. Biochar sucks Co2 out of the air and puts it in the soil! An amazing new ‘wedge’ in our fight against Global Warming
  6. Kalannie plant to do 50,000 tonnes per year
  7. Silly objection: It’ll take too much energy to move around!
  8. If economics proves prohibitive to transport, take the biochar cooker out to the farmers!
  9. Reasonable concerns with biochar
  10. Polyface farm, Crop and cow rotation, low tillage farming and other integrated large scale ‘industrial permaculture’ systems
  11. Podcasts I listen to on the fascinating story of DIRT!

1. Soil, an incredible new science!

Believe it or not, soil is an exciting new science where astonishing breakthroughs are just beginning to occur! I am likely to tinker with this page some more over the coming years simply because of the startling new developments in our understanding of soil.

“We know more about the movement of celestial bodies than about the soil underfoot.” – Leonardo da Vinci, circa 1500s”In many ways the ground beneath our feet is as alien as a distant planet. The processes occurring in the top few centimenters of Earth’s surface are the basis of all life on dry land but the opacity of soil has severely limited our understanding of how it functions…. However, perspectives are beginning to change… Interest in soil is booming, spurred in part by technical advances of the past decade.”
Science, June 2004.
For more see Energy Bulletin

The agricultural solutions I am most interested in are permaculture-like applications that bring the soil back to life and create lasting solutions to our food needs, but that can be applied on an industrial scale!

So while I love permaculture and the dynamic systems thinking involved in projects like this ‘greening the desert’ video that definitely bring soil back to life and save heaps of water, I am interested in how similar concepts can be scaled up and operated at the western agribusiness scale. The western world has a very stratified society with only about 5% involved in actually producing food, and I’m not one of those doomers that advocates us all going back to subsistence farming and most of us becoming potato farmers!

On the other hand, even though this looks quite labour intensive and does not meet my requirements above, the permaculture “Greening the desert”  project could be applicable in various developing nations and 3rd world contexts, until such time as they develop more stratified economies of their own. I love this project!

2. Water solutions

As I highlighted on my soil crisis page, the world is facing increasing water stress and shortages that threaten to become droughts of biblical proportions. Fortunately there are a variety of new water efficiency, recycling and desalination technologies that may even begin to supply water at an agricultural scale. (Which is an impressive statement, as agriculture demands much more water than our cities which are increasingly being supplied by desalination).

The Seawater Greenhouse may work in desert regions close to oceans. The brilliance of this concept is that the greenhouse can be built to be cooler than the surrounding desert for optimal crop growth. It only requires the energy to pump the seawater to the greenhouse, instead of the truly vast quantities of energy needed to boil the freshwater out of the brine in traditional desalination. Finally, it produces enough water to grow all the crops in the greenhouse and five times more can be stored or released into the surrounding desert environment!

Seawater Greenhouse

Couple this technology with the water conservation and shade tree growing strategies of the “Greening the Desert” video at point 1 above, combined with the next subject, and we could bring much of the Sahara desert back to life! (Of course we’d leave an enormous desert park for the desert wildlife and ecosystems that have evolved there. I’m only dreaming about reversing the damage humans have inflicted on the African continent.)

Let us not forget that Australian concept of the ‘Water Highway’, invented by Max Whisson.

Dr Max Whisson, an inventor from Perth, Western Australia, believes that he has discovered a way to produce 200,000 litres of fresh water a day in a dry land. Max’s idea is to build a 1,000 km long 10 metre wide water producing freeway running a long distance inland from the sea then returning back to the sea again.

Max explained on the ABC’s Australian Story Program that the ocean contained an endless supply of fresh water that could easily be extracted by using thermal solar energy. Max’s scheme is to run a number of large parallel black pipes carrying sea water along this large scale water producing freeway. The 10 metre wide series of pipes would be covered by a transparent perspex cover. Daytime solar heat will cause the water in the pipes to heat up and 70% to 80% of the fresh water will evaporate off in a series of hot ponds in the circuit. Max Whisson said that hot air from the pond surfaces will be ducted up to condensation sheds where cooler atmospheric air causes distillation of the fresh water. At the end of the water road, the salty brine is returned to the sea or it could be used to produce sea salt, Dr Whisson said.

3. Phosphorus solutions: recycling sewage + council composters

The Sustainable Agriculture wiki points out that soil requires all sorts of amendments and inputs:

What grows where and how it is grown are a matter of choice. Two of the many possible practices of sustainable agriculture are crop rotation and soil amendment, both designed to ensure that crops being cultivated can obtain the necessary nutrients for healthy growth.

To save phosphorus we must create closed nutrient cycles. Phosphorus currently goes on a complex one way journey from the mines onto our farms, into our food, and then down the toilets and out to sea. This is a nutrient leak! Permaculture systems thinking must be applied to the way we process our sewage.

Our council green bins can also carry kitchen waste and food scraps. Many city folk are not that interested in gardening or running their own composts. So the answer could be placing kitchen scraps in biodegradable plastic bags and throwing them in the green bins, which the councils then collect and process in a local centre. As the ABC environment podcast says:

A lot of kitchen waste is dumped into landfill. At the same time, farmers are crying out for nutrients to add to their soils.

The solution is obvious. Someone should collect all those scraps and turn them into compost.

Kim Russell has taken on the challenge.

He’s executive director of Zero Waste Australia and he wants to get organic waste out of landfill and onto farms.

Repeatedly growing the same crops in vast monoculture farming drains the soil and does not put anything back, and as we saw on the soil crisis page, is ultimately destroying the soil. Unless we return the minerals we are ‘mining the soil’. Indeed, some sustainable agriculture planners are so concerned about peak phosphorus (and other fertiliser problems and soil inefficiencies) that they are even making town planning decisions based on the quickest way to get the ‘nutrients’ back into the soil!

Correctly managing phosphorus is an important step in bringing the soil back to life. It must be recycled (see wiki on capturing phosphorus from sewage). We need to be as efficient as possible with phosphorus and indeed all fertilisers, as this both saves resources and limits the NPK runoff that is destroying rivers and creating oceanic dead zones.

4. The ultimate soil amendment — biochar!

A remarkable new system of agriculture is breaking out all over the world. Field studies by leading soil scientists are yielding truly stunning results. The process is to take biomass (such as agricultural wastes like corn stalks, wheat stems or rice husks) and throw them in a “low oxygen cooker” process known as Pyrolysis. This produces energy (syngas) and charcoal. The charcoal is returned to the soil where it becomes a habitat for all sorts of micro-organisms and fungi. The fungi grows in all the nooks and crannies of the charcoal, sucking Nitrogen and more Co2 out of the air as it grows through the soil, adding organic mass. This partially fertilises the soil, reducing the fertiliser requirements of agriculture.

At BestEnergies half of the syngas is then used to cook the next load of Biomass into Biochar, and the other half can be used for energy. This process can yeild some sustainable energy, permanently lock away carbon and rejuvenate the soil all at the same time!

Rob from Transition Culture attended a lecture with the following summary ratio of Biochar products.

“…The machine they have developed for doing the charcoal burning basically takes 10 tons of any woody or plant biomass and turns it into 1 ton of charcoal and 3.2 tons of diesel.”

Check out this must read article by Big Gav at Terra Preta: Biochar and the MEGO effect | Energy Bulletin. Note that I do not regard biochar as solving our liquid fuel energy needs, but it might just provide some niche fuels for the farming sector.

Why does Charcoal have such a powerful effect?

Before I continue I should point out that Biochar reduces fertiliser inputs, it does not eliminate them. However by making fertliser and water uptake so much more efficient, it increases crop yeilds and on-site economics for the farmer.

As Keplie Wilson of puts it…

“Field trials and experiments in pots show impressive yield gains in charcoal-amended soils, but so far researchers don’t completely understand why. One question is whether the effect is primarily chemical and physical or primarily biological. Charcoal is a highly porous material that is very good at holding nutrients like nitrogen and phosphorus and making them available to plant roots. It also aerates soil and helps it retain water. Charcoal’s pores also make excellent habitat for a variety of soil microorganisms and fungi. Think of a coral reef that provides structure and habitat for a bewildering variety of marine species. Charcoal is like a reef on a micro-scale.

One of the research papers presented at the conference documented an increased diversity of beneficial microbes in terra preta soils as compared with unamended soils, but there are still no answers about whether the fertility increase is due to physical or biological factors. The best answer may be that it is both.”

Not only that, but it retains other NPK nutrients as well.

Lehmann explains that nutrients from plant and animal remains—like nitrogen, phosphate, and potassium—bind to charcoal or biochar, drastically reducing how much is washed away by the constant rains. It is a gradual process that begins with the charcoal breaking down in the soil over time. Tiny pores in the charcoal, along with changes in its chemistry, provide more surfaces for nutrients to adhere to, which in turn encourages microorganisms to colonize the soil. “With a handful of biochar you can keep many more nutrients in the soil than with a handful of mulch or compost. It is like mopping up nutrients with a magnet that looks like a sponge—that is, it has high surface area like a sponge but can attract a thin layer of material like a magnet,” Lehmann says.
Discover Magazine

Other references for biochar

ABC’s Catalyst 2007: Reduces nitrous oxide emissions from farming! (Thankfully these emissions are relatively smaller than Co2 because they are hundreds of times more powerful than Co2, and eliminating them is very important. They are caused by over-use of Nitrogen fertilizer, which Biochar helps reduce the use of anyway.)

The Case for burying Charcoal at Technology Review shows that it is cheaper and safer than carbon geo-sequestration or so called “clean coal”.

University of Georgia — Can work with wood chips!

The International Biochar Initiative (IBI)

Eprida — It builds soil organic content with Mychoryzal Fungi as described above

The Biochar wiki is now gaining momentum and scope.
Beyond Zero Emissions — an Australian global warming activist group — have many podcasts on Biochar.
Best Energies
Advanced Biorefinery — Green chemicals
Technology review — Turning Slash into cash

5. Biochar sucks Co2 out of the air and puts it in the soil! An amazing new ‘wedge’ in our fight against Global Warming!

An International Biochar Initiative PDF states:

2. What is IBI’s goal for carbon removal from the atmosphere?
IBI is focusing presently on the feasibility of one “wedge,” which equals one gigaton of carbon per year. The term “wedge” comes from an often-quoted analysis (Pacala and Socolow, 2004) showing a need to have seven gigatons of carbon per year (seven wedges) of reduced carbon emissions by 2054 to keep emissions at the 2004 level.
3. Is a one gigaton per year biochar wedge achievable by 2054?
Yes. In the four basic scenarios we have examined, we found several ways to create at least one wedge by 2054.

Rob from Transition Culture again — note this is about on site small char units that might only produce char, not the larger commercial plants that will produce char and energy.

“…the idea is that farmers have one of these units on their farms, grow their crops, put the residues in the machine, get paid in carbon credits for doing so, make the charcoal which they add to their soils, and produce diesel for themselves and to sell. Lietaer said that a land mass the size of France using this system could lock up all the carbon the world needs to.”
Transition Culture

Further discussion about small scale on site Biochar at The Oil Drum.

Worldchanging continues the discussion about ultimate potential in Black is the new green.

The difference between terra preta and ordinary soils is immense. A hectare of meter-deep terra preta can contain 250 tonnes of carbon, as opposed to 100 tonnes in unimproved soils from similar parent material, according to Bruno Glaser, of the University of Bayreuth, Germany. To understand what this means, the difference in the carbon between these soils matches all of the vegetation on top of them. Furthermore, there is no clear limit to just how much biochar can be added to the soil.

Claims for biochar’s capacity to capture carbon sound almost audacious. Johannes Lehmann, soil scientist and author of Amazonian Dark Earths: Origin, Properties, Management, believes that a strategy combining biochar with biofuels could ultimately offset 9.5 billion tons of carbon per year-an amount equal to the total current fossil fuel emissions!
Black is the new green

Even Tim Flannery, author of “The Weather Makers” and 2007 Australian of the Year, has stated to Podcast “Beyond Zero Emissions” that permanently sequestering “6 gigaton per annum … is eminently feasible”.
(About 9 minutes into 24 minute podcast).

6. Kalannie plant to do 50,000 tonnes per year

Managing director Peter Burgess says wheat straw would provide the raw material for the plant.

“The project will take wheat straw, large square bales of wheat straw, and convert that into biochar.”

“We’re just finishing the detailed design of the plant and we expect to start building something later this year.”

Mr Burgess says he would expect the Kalannie plant to be up and running by the end of the year.

via First biochar plant closer – 31/03/2010.


The company has partnered with Crucible Carbon to develop the pyrolysis technology and will build a demonstration node at Kalannie later this year. The node will process 10,000 tonnes of waste plant material per year until the demonstration is successful and will then process 50,000 tonnes per year.

via Biochar breakthrough benefits environment and energy.

7. Silly objection: It’ll take too much energy to move around!

Remember how much fuel biochar produces.

“…The machine they have developed for doing the charcoal burning basically takes 10 tons of any woody or plant biomass and turns it into 1 ton of charcoal and 3.2 tons of diesel.”

Today’s road trains can carry anywhere from 100 to 200 tonnes! That is a very efficient way to freight huge quantities of biomass to biochar power plants. Basically, one road train collects 200 tonnes of biomass from the farm/s. It takes it to the biochar plant, and after processing forms about  20 tonnes of biochar and 64 tonnes of diesel to sell back to the farm/s. 64 tonnes of diesel! (Which could be even more if the syngas is not used to cook up the next batch of biochar, but they used the nuclear grid or even local CSP!)
Road trains

How much biomass would there be to process each year? Is the ratio of one biochar power plant for every 100km too large an area, or not enough? Where does the biochar plant get enough biomass in between harvesting seasons? How often would the road trains, trucks, and / or regular rail trains need to run through a region to pick up the biomass and return with biochar and synfuel? I’m not even going to bother attempting to model these issues because just as there are a variety of crops, growing seasons, and agricultural belts around Australia and around the world, so to will there be a variety of appropriate and inappropriate biochar solutions. The biochar businesses with money on the table will run feasibility models and answer many of these questions, and come up with unique solutions. At the right ratio of biochar plants to local region, the biochar plant will be busy cooking up the backlog of biomass from last years growing seasons. If they overdo it, there won’t be enough biomass to go around and so the biochar plants may be sitting quiet and some might go bankrupt. The marketplace and local realities will sort it out.

8. If economics proves prohibitive to transport agriwaste to the biochar cooker, take the biochar cooker out to the farmers!

Bigchar has already launched, and brings the biochar cooker to the farm! They currently have a mobile biochar cooker already in operation, but it is not yet fitted out with the mini-refinery to catch the syngas and convert it into synfuel. They are investigating the commercial viability of such a scheme.

Bigchar Mobile biochar cooker

ABC rural reports:

“One of the problems with biomass is, that it’s a low density, low value material, so it’s really not cost effective to transport it big distances.”

He says the process is now more viable because farmers can take the machine out to where the biomass is.

There are mobile biochar units that process the agriwaste on the farm, cook up the biochar, and also save the syngases!

9. Realistic concerns with biochar

Does not replace fertilisers use completely

Scientific America
highlights that it does not quite behave like the original Terra Preta soils from the Amazon basin, but could be the development of a bold new science. SCIAM also raises the possibility that it accelerates leaf breakdown in forests which speeds up the natural return of Co2 to the atmosphere, but the last time I looked we don’t grow our grains in forests. Farmers are already desperate for Biochar, and can’t get their hands on enough of the stuff! It will be too valuable to waste in forests.

Growth paradigm

If we use Biochar to keep growing across the planet, will we pave over, plough up and pollute the last of the irreplaceable ecosystems we have left? If a growth paradigm encourages us to use Biochar to plough the last surviving ecosystems into oblivion, will the planet really be any better off? We need more National Parks and World Heritage sites than ever before. Legislation needs to be implemented to protect the remaining biodiversity. But what biodiversity losses will there be if we let Global Warming continue unabated? I say get into the Biochar now, big time, as well as conserving the last of our parks and biodiversity.

10. Crop and cow rotation, low tillage farming and other integrated large scale ‘industrial permaculture’ systems

We all know of the old techniques allowing fields to sit idle as rain gradually replenishes the nitrogen in the soil, or even faster crop rotation, which grows nitrogen fixing plants either in-between seasons or in the fallow year, which are then raked into the topsoil.

Crop rotation is the practice of growing a series of dissimilar types of crops in the same area in sequential seasons for various benefits such as to avoid the build up of pathogens and pests that often occurs when one species is continuously cropped. Crop rotation also seeks to balance the fertility demands of various crops to avoid excessive depletion of soil nutrients. A traditional component of crop rotation is the replenishment of nitrogen through the use of green manure in sequence with cereals and other crops. It is one component of polyculture. Crop rotation can also improve soil structure and fertility by alternating deep-rooted and shallow-rooted plants.
Crop rotation wiki

But what about rotating between agricutlure and grazing, between growing plants and growing cattle?

As farmers begin to abandon deep soil tillage — which has been described by ABC’s Landline as a “bushfire in the soil” — they also start to experiment with substituting other practices instead of industrial chemical fertilisers. Indeed, the hero of this Landline story is Cam McKellar, who is experimenting with what I call “Crop and cow” rotation which is developing a careful synergy between cattle management as they eat out the waste stubble from last season’s crop.

Add more than four tonnes of wet manure a day into the mix and it’s an important element of what Cam McKellar calls biological farming.

“It means anything to get away from what we have been using in the past, basically acid fertilisers and as many insecticides as possible.
Landline October 2004

Another project that is attracting international attention is the Polyface Farm system integrating both animals and cropping together to create soil hundreds of times faster than nature. Straight from the wiki:

Salatin bases his farm’s ecosystem on the principle of watching animals’ activities in nature and emulating those conditions as closely as possible. Salatin grazes his cattle outdoors within small pastures enclosed by high-tech, electrified fencing that is easily and daily moved at 4pm to ensure that the animals always have fresh grass; grass has had time, about 100 days, to mature and grow tall, which increases levels of starch. Animal manure fertilizes the pastures and enables Polyface Farm to graze about four times as many cattle as on a conventional farm, thus also saving feed costs. The small size of the pastures forces the cattle to ‘mob stock’-to eat all the grass.

Portable coop

In addition his chickens are housed in portable coops that follow 4 days after the cattle, when flies in the manure are pupating; the chickens get 15% of their feed from this. The chickens while finding the pupae distribute the manure across the field.[3] Salatin’s pastures, barn, and farmhouse are located on land below a nearby pond that “feeds the farm” by using 15 miles of piping. Salatin also harvests 450 acres of woodlands and uses the lumber to construct farm buildings.[4] One of Salatin’s principles is that “plants and animals should be provided a habitat that allows them to express their physiological distinctiveness. Respecting and honoring the pigness of the pig is a foundation for societal health.”[5]

Media Attention

Polyface Farm was featured in the book The Omnivore’s Dilemma by Michael Pollan as exemplary sustainable agriculture, contrasting Polyface Farm favorably to factory farming. An excerpt of the book was published in the May/June 2006 of Mother Jones magazine. The farm is covered in the August/September 2008 issue of Mother Earth News. [6] Pollan’s book describes Polyface Farm’s method of exemplary sustainable agriculture as being built on the efficiencies that come from mimicking relationships found in nature and layering one farm enterprise over another on the same base of land. In effect, Joel is farming in time as well as in space—in four dimensions rather than three. He calls this intricate layering “stacking” and points out that “it is exactly the model God used in building nature.” The idea is not to slavishly imitate nature, but to model a natural ecosystem in all its diversity and interdependence, one where all the species “fully express their physiological distinctiveness.” [7]

The farm is also featured in the documentary film Food, Inc. [8].

Polyface Farm is a participant in Humane Farm Animal Care‘s Certified Humane Raised and Handled program.

I like the thinking behind this guy’s work! But if I have one criticism, is that it seems expensive. The social justice branded into my brain studying my Advanced Diploma years ago forces me to side with the Mother Jones reporter that asks the hip-pocket questions.

I asked Joel how he answers the charge that because food like his is more expensive, it is inherently elitist. “I don’t accept the premise,” he replied. “First off, those weren’t any ‘elitists’ you met on the farm this morning. We sell to all kinds of people. Second, whenever I hear people say clean food is expensive, I tell them it’s actually the cheapest food you can buy. That always gets their attention. Then I explain that, with our food, all of the costs are figured into the price. Society is not bearing the cost of water pollution, of antibiotic resistance, of food-borne illnesses, of crop subsidies, of subsidized oil and water—of all the hidden costs to the environment and the taxpayer that make cheap food seem cheap. No thinking person will tell you they don’t care about all that. I tell them the choice is simple: You can buy honestly priced food or you can buy irresponsibly priced food.”

via No Bar Code | Mother Jones.

Radio National also investigated an Australian ‘green cow’ movement where cows were allowed to intensively graze certain patches of field, fertilise it, and then move on to graze the next patch of field: while increasing soil biodiversity and health and this having spin-off effects through the local kangaroo and bird populations.

However, whether Cam McKeller in Australia or Salatin in the USA, it’s great to see these guys coming up with new systems to get past industrial agriculture. It seems that once the focus turns to soil and broader farm health and resources, farmers have a few more tricks up their sleeves than just nuking the soil with industrial petrochemical products!

My only niggling issue so far is that I haven’t heard how the phosphorus and other rarer minerals are returned to the farm. For make no mistake, these customers still take away their meat and egg products, eat them, and flush the wastes out to the sewage treatment centres and then out to sea. If we can fix that phosphorus leak by recycling the sewage somehow, then as the youth of today say, “It’s all good”.

Other References

Wiki on Soil conservation
Wiki on Soil erosion
Australian Academy of Science — Feeding the future – sustainable agriculture
News: Positive agriculture news at Worldchanging and enter “agriculture” in the search field
News: Both positive and negative try the Energy Bulletin Food and Agriculture section.

11. Podcasts I listen to on the fascinating story of DIRT!
(And alternative farming practices)

I love the ABC. ABC podcasts fire up my passion for DIRT! Check the following thread of podcasts in their “Hunger Pains” category. The future of food has never had so many high quality podcasts!

Then of course there is the environment podcasts.

Of particular interest is “The History of Dirt” in which Professor David Montgomery believes that societies can fall apart when they lose their soil.

Council collection of compost

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