Do you have a Black Thumb?
Charcoal and Gardening
Charcoal is used as a top dressing for gardens, lawns and golf greens. Used in potting soils and bedding compounds, charcoal works as a soil sweetener while it neutralizes pesticides and herbicides. It is also a natural insecticide for some insects. It is both a fertilizer and an insecticide for roses. Charcoal “by any other name would be as sweet”.
In this Issue we will take a brief look at some of the many uses of charcoal in modern agriculture. We will then go back to the ancient practices of the Amazonian peoples and then finish with a glimpse into how those ancient practices have captured the attention of major agricultural universities and environmental and governmental organizations.
The North Carolina Cooperative Extension Service in drafting their Using Activated Charcoal to Inactivate Agricultural Chemical Spills, state: “Activated charcoal is the universal adsorbing material for most pesticides.”
Sometimes it becomes necessary to stop the activity of an applied herbicide, perhaps because of an accidental spill, perhaps because of a weed-control and grass-seeding combination. Activated charcoal adsorbs one hundred to two hundred times its own weight and comes in handy for binding, thereby deactivating some herbicides. Turf areas that have been treated with pre-emergence herbicides can be reseeded earlier than normal by treating with activated charcoal.
Activated charcoal will reduce the level of most organic pesticides in the soil, but is considered ineffective for inorganic pesticides and for water-soluble organic pesticides. It is a good idea to keep a bag or two of activated charcoal in stock at all times so it can be applied almost immediately after an accidental spill or application. If the active material has not been diluted with water at the time of the spill, apply the charcoal dry. If it has been diluted with water, apply the activated charcoal in a slurry.
The charcoal must be incorporated into the contaminated soil, preferably to a depth of six inches. With severe spills, some of the contaminated soil may need to be removed prior to the activated charcoal application. It is easier to apply activated charcoal as a water slurry, so this is the best way to go when possible. The final spray mixture should contain one to two pounds of charcoal per gallon of water, and there should be enough water to begin moderate agitation until a uniform mixture is attained. Maintain moderate agitation while spraying.
For reducing the effects from spills of organic pesticides, some petroleum products and hydraulic fluids, use one hundred pounds of activated charcoal for every pound of active material spilled, but no less than two pounds per 150 square feet (600 pounds per acre) of contaminated area.
For turf areas that have been treated with pre-emergence herbicides, apply charcoal slurry at a rate of one pound per gallon of water for each 150 square feet. Wash the grass free of any heavy charcoal deposits, and, ideally, rake the charcoal into the soil. The area can be reseeded twenty-four hours after treatment.
To avoid the mess of a fine-powdered charcoal, look for granulated product that dissolves easily. It can be spread by a walk-behind spreader without dust or irritation.1
Plant poisons
Jugalone is a natural hormone produced by black walnut trees, and is toxic to the roots of plants that encroach on the walnut’s space. Moreover, when walnut trees are cut down, the decaying roots still produce the poison, causing a build up of jugalone in the soil. Charcoal can be spread around the area as a thick slurry and washed into the soil, or it can be worked in.
Irrigation
Just as the ecosystems of nature are interconnected, so too there are related issues around environmental stewardship. In California, alfalfa production uses more water than any other crop – almost twenty percent annually of the state’s agricultural water use. Because of the use of irrigation systems, there is an increasing concern that unacceptable amounts of chemical fertilizers, herbicides, and insecticides will end up contaminating the already compromised ground water supplies. Recommendations are now in place urging the use of activated charcoal and other filtering agents, in conjunction with different containment strategies, to hold and clean surface-water run-off before water leaves a ranch into ditches, irrigation canals, ponds and rivers.2
Plant Food
While charcoal helps to clean the soil of pollutants, it also acts as a soil conditioner. It is used as a top dressing for gardens, bowling greens and lawns. Charcoal also acts as a substitute for lime in soil additives because of the high potash content, and it can be a little cheaper than lime. It is used for potting and bedding compounds as a soil and mulch sweetener, and as a fertilizer and insecticide for roses. Some orchids seem to love it. One study showed that adding charcoal to the rooting medium of peas produced a marked increase in the weight of the pea plants and in nitrogen fixation by the plants as compared to controls.3 It is suggested that the benefits derived from charcoal are due to its adsorption of toxic metabolites that are often released by plant tissues, especially when the tissues are damaged.4
Here are some planting tips using charcoal chips. Start with a plastic liner in a tray. Add half an inch to an inch of gravel in the bottom for drainage. Next, sprinkle enough charcoal chips to cover the gravel layer. Charcoal will help keep bacteria at bay. Top this with potting soil and add your plants.
Insect killer
Dating back to 1947, several studies have been conducted showing the benefits from activated charcoals in protecting seeds, seedlings, and crops from some organic pesticides and from the effects of herbicides applied to the soil to inhibit weed growth.
One study demonstrated that, as an insecticide, powdered charcoal is a more potent deterrent to the Tribolium castenum beetle, than are powdered clays. Commonly known as the Red and Confused flour beetles, these pests attack stored grain products such as flour, cereals, meal, crackers, beans, spices, pasta, cake mix, dried pet food, dried flowers, chocolate, nuts, seeds, and even dried museum specimens.
In fact, these beetles are considered two of the most damaging pests of stored products in the home and in grocery stores. It is speculated that the superior bleaching and desiccating properties of powdered charcoals accounts for its success in killing these pests.5
Dead Trees Revive Sick Trees
Just in. I listened to a doctor today explain how some people in an area of a forest fire had taken the scorched dead trees and cut them up and piled them around the base of other sick and dying trees (unknown cause). They found that the sick trees were being restored to health. Hmmm, dead trees revive sick trees.
Please let us know of your experiences, no matter how off-the-wall they may seem. They may not be so off-the-wall as you would think. Read on.....
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1 Adapted from University of Florida Fact Sheet #ENH-88 Activated Charcoal for Pesticide Deactivation)
2 Cline, Harry, Western Farm Press, Jan 24, 2004
3 Vantis, JT, and Bond, G, The effect of charcoal on the growth of leguminous plants in sand culture, Annals of Applied Biology, 37, 159, 1950.
4 Cooney, David O, Activated Charcoal in Medical Applications, Marcel Dekker Inc., p.559, 1995
5 Majumder, SK, Narasinhan, KS, and Subrahmanyan, V. Insecticidal effects of activated charcoal and clays, Nature, 184,p 1165, 1959
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Terra Preta
Terra Preta – (Portuguese) “dark earth”
Terra preta was first documented in 1879 and has been studied scientifically since 1966. The American Association for the Advancement of Science conference in January 2006 dedicated a session to terra preta. Later, in July 2006 at the World Congress of Soil Science, an interdisciplinary group of agrichar enthusiasts got so fired up that they banded together to form the International Agrichar Initiative. The group is held its first conference in April 2007 in Australia. What is terra preta?
Amazonian Dark Earth, or terra preta do indio, has mystified science for the last hundred years. Three times richer in nitrogen and phosphorous, and twenty times the carbon of normal soils, terra preta is the legacy of ancient Amazonians who predate Western civilization. Scientists who long debated the capacity of 'savages' to transform the virgin rainforest now agree that indigenous people transformed large regions of the Amazon into amazingly fertile black earth. The Amazonians' techniques remain an enigma but are believed to have used slash-and-smolder to lock half of the carbon in burnt vegetation into a stable form of biochar (definition) instead of releasing the bulk of it into the atmosphere like typical slash-and-burn practices.
The difference between terra preta and ordinary Amazonian soils (oxisol) is immense. A hectare of meter-deep terra preta can contain 250 tons of carbon, as opposed to 100 tons in unimproved soils from similar parent material, according to Bruno Glaser, of the University of Bayreuth, Germany. In other words, terra preta soils have as much carbon as 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.
Besides the amazing growing ability of terra preta soils there is also has the amazing potential to sequester tremendous amounts of carbon that could theoretically offset the greenhouse effect that is so much in the news. 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!
One company EPRIDA, unlike some other giants, is developing small plants capable of producing 12 tons of enriched biochar a day besides biodiesel that could be utilized by small farm operations. Company president Danny Day explains:
"Our primary goal is to increase the quality of life for subsistence
farmers, and in doing so we have the capability of reversing CO2 release and converting that whole cycle downwards...
The Eprida technology uses agricultural waste biomass to produce hydrogen-rich bio-fuels and a new restorative high-carbon fertilizer (ECOSS) ...In tropical or depleted soils ECOSS fertilizer sustainably improves soil fertility, water holding and plant yield far beyond what is possible with nitrogen fertilizers alone. The hydrogen produced from biomass can be used to make ethanol, or a Fischer-Troupsch gas-to-liquids diesel (BTL diesel), as well as the ammonia used to enrich the carbon to make ECOSS fertilizer.
We don't maximize for hydrogen; we don't maximize for biodiesel; we don't maximize for char...By being a little bit inefficient in each, we approximate nature and get a completely efficient cycle.”
But, the practical benefit for the moment is plant growth. Trials at Australia's New South Wales Department of Primary Industries’ (DPI) Wollongbar Agricultural Institute show that crops grown on agrichar-improved soils received a major boost. The Australian trials of 'agrichar' or 'biochar' have doubled and, in one case, tripled crop growth when applied at the rate of 10 tons per hectare.
There is an ecology going on in these soils that is not completely understood, and if replicated and applied at scale would have multiple benefits for farmers and environmentalist.
Terra preta creates a terrestrial carbon reef at a microscopic level. These nanoscale structures provide safe haven to the microbes and fungus that facilitate fertile soil creation, while holding carbon for many hundred if not thousands of years. The combination of these two forms of sequestration would also increase the growth rate and natural sequestration effort of growing plants.
One can instantly see the benefit of charcoal from the picture below. An unimproved piece of turf soil was rototilled and sewn with a row of corn seed. The control in the middle is unimproved soil with added raw charcoal on the right, and nitrogen enriched charcoal produced from biochar supplemented on the left. Even without the advantage of enriched charcoal the difference is dramatic not only in growth but color and vitality.
There are other pictures posted on the links at the bottom of this page.
Imagine, a natural fertilizer that improves the soil, improves crop yields, aids in controlling greenhouse gases, and increase global security – all kinds of terrorists can’t blow it up. Talk about a healthier safer world! And all this without further straining forests in Africa, Asia, and South America for charcoal. The primary sources for these biochars are waste products from such diverse things as nutshells, corn stover, switch grass, and peanut hulls.
While some are waiting for government subsidies, I liked the poetry and vision of David Zaks and Chad Monfreda in the conclusion to their article Terra Preta: Black is the New Green on WorldChanging.com.
“Terra preta's full beauty appears in this closed loop. Unlike traditional sequestration rates that follow diminishing marginal returns (aquifers fill up, forests mature), practices based on terra preta see increasing returns. Terra preta doubles or even triples crop yields. More growth means more terra preta, begetting a virtuous cycle. While a global rollout of terra preta is still a ways away, it heralds yet another transformation of waste into resources.
How ironic it is that ancient humans cultivated the very fertility of Earth's most pristine places so seamlessly as to be nearly invisible. Perhaps then our challenge as planetary gardeners is not to preserve nature in a bubble but to reweave ourselves into it-to invert our footprints into handprints.”
With that I am off to our new garden spot for a whole new learning curve. We are new "tenants/stewards" on this acreage we live on here in NW Nebraska. The ground has been fallow for years. It is windy and the area has been in a drought for eight years. Our well only produces 2.5 gallons/min. In some ways it reminds me of when I taught organic gardening on a remote Pacific desert island (Rep. of Kiribati) - only sand for soil and precious little water. But after preparing this article I know now I have one amazing resource, charcoal. If I had only known then, we could have converted the abundance of coconut husks into charcoal and started the first inland "Charcoal Reef". Once again the Creator has
provided mankind everywhere with a remedy not only for sick bodies and sick
animals, but also for the sick earth that, at its creation, was
pronounced "Very good!" (Genesis 1:31)
We have 150 bare-rooted trees coming this month. I will post our survival rate and some garden pictures later this fall - God willing. We would invite you "green thumbs" out there to do your own experimenting and give us your experiences to share.
Till then, God's blessings.
john dinsley
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For further agricultural research on charcoal please visit the links on our section on Gardens and Farms.
There are numerous websites that explore the world of Terra Preta and its implications. All you have to do is Google “Terra Preta” “biochar” or “agrichar”. Here are a few links:
EPRIDA
International Biochar Initiative
