by David Yarrow
Biochar is seen as a valuable soil amendment and much attention has been placed on using biochar to boost soil fertility and microbiology, upgrade soil structure and accelerate plant growth. Amid a rising tide of research and trials, what was once mostly fuel or water filtration media suddenly sprouted dozens of innovative applications and benefits.
New biochar uses are being discovered, including:
- Stormwater management and treatment
- Phosphorus traps to reduce water pollution
- Nitrogen traps to reduce ammonia and nitrate pollution
- Reclamation of mine tailings
- Building material blended with cement, mortar, plaster, etc.
- Electronic microwave shielding
- Electron storage and release as a “super-capacitor”
- Carbon fiber textiles for odor-absorbent clothing
- Carbon nanofibers to replace plastic and metal
Livestock farming is offering a new and growing area of unexpected uses for biochar. Animals from earthworms to chickens, cattle and even monkeys, show shrewd interest in biochar added to their food. Farmers and scientists around the globe have investigated the use of biochar in livestock production. In the European Union biochar is carefully defined and approved for use in agriculture. Currently, most is fed to livestock and then spread on land with manure.
This article mainly addresses poultry production, but similar issues and opportunities face other livestock producers. Research from several countries shows that adding 1 to 3 percent biochar to cattle feed improves feed efficiency by 28 percent, reduces methane by 25 percent and increases rate of weight gain by 20 percent.
Biochar Added to Litter
An immediate use of biochar in poultry farming is to reduce — and even eliminate — odors from poultry litter, particularly ammonia. Biochar adsorps gases, liquids and ions, and ammonia (NH4+) is all three. Adsorption is the adhesion in an extremely thin layer of molecules to the surfaces of solid bodies or liquids with which they come into contact. Activated carbon’s effectiveness for odor control is well-known and is preferred in air purifiers. Farmers can spread a blend of 5 to 20 percent biochar with conventional litter on a barn or coop floor.
Ammonia’s strong positive electric charge makes it corrosive and toxic to breathe. This gagging gas is emitted by bird droppings, creating unhealthy, toxic air to birds and humans. Ammonia irritates skin on contact and degrades even hard tissue, such as hooves. It also attracts insects, such as flies.
Adsorption with Biocarbon
Biochar is extremely porous, making it an excellent natural filter with a huge internal capacity for water and ions. Biochar has a more robust appetite for ammonia, ions and other irritants and nutrients than any other organic material.
Biomass burned or baked with little or no oxygen is “reduced” to a very black, inert, dry, porous substance. In this contracted, scorched state, char is ready to vigorously attract and absorb minerals, molecules, ions, electrons and even photons.
Careful attention to biomass source, temperature and time can produce a grade of biochar optimized for this barnyard adsorption service. Research at several universities shows activated carbon captures up to 63 percent of ammonia emitted from poultry poop. Char also curbs methane, nitrous oxide, hydrogen sulfide, urea, organic acids, ketones, volatile vapors and noxious liquids. Biochar keeps these chemicals safely in litter, rendering them non-toxic and immobile and converting them to precious nutrients. Biochar doesn’t do all this on its own, but supports minerals and microbes needed to digest, break down and convert wastes.
Depending on type of litter, biochar can be mixed 5-10 percent by volume with litter. Effects are strong at 5 percent biochar and reach saturation beyond 15 percent. For best effect, biochar should be screened to uniform particle size (1/4 to 1/16 inch), cleaned of dust, dusted with calcium, trace elements, clay and rock flours, lightly moistened and inoculated with digestive bacteria and fungi. With straw pellets as litter, char is best added at pelleting stage.
Reduced ammonia is a major health improvement for the environment, birds and farmworkers. Lower moisture content and ammonia levels curtail risk of footpad diseases, skin lesions and respiratory afflictions and infections heal as animals’ resistance improves to benefit vitality, egg production and final weight.
Because biochar also absorbs liquids, it changes the physical quality of poultry poop. Floor droppings are far less sticky, almost dry, lighter in weight and easier to handle, allowing litter and bedding to be handled with greater safety and sanitation.
Commonly, lime and other cations are added to litter to help reduce odors and raise pH. Biochar’s high adsorption capacity means less lime is needed, since calcium and other cations are adsorped into char micropores and delivered with greater efficiency. Char captures and conserves calcium and other cations, holding them where microbes and roots can access them. This further reduces ammonia emissions and improves litter’s value as soil amendment.
Char can also be added when making silage. Char mixed with silage is bound well and doesn’t rub off, and it provides its usual benefits of conserving moisture, buffering pH, retaining cations and anions and provides stable refuges for fermenting microorganisms.
Biochar in Compost
When litter or bedding is spread on land, significant nutrients outgas and leach. Biochar bestows significant extra capacity to adsorp and hold nutrients in composting materials. Biochar improves retention of ammonia and other valuable nutrients, beginning with nitrates and phosphates, with far less lost as gas and leachate. Biochar also retains water in its micropores and keeps moisture in the composting biomass.
Biochar’s micropores absorb water out of the soil solution and conserve that water to keep soil wetter. In contact with biocarbon, water forms thin films and nanostructures, and shifts from freely-moving “blue water” to a captive, contained form of “green water,” which is held in a biological context, such as the bodies and protoplasm of living cells and organisms.
Biochar is derived from plant biomass and creates an environment that benefits cell biology. Providing air, water and nutrients favors healthy, beneficial microbes to improve composting rate and digestive efficiency. Biochar micropores are ideal refuges for bacteria and fungi, so adding this uniquely inert biocarbon stabilizes, strengthens and sustains compost’s teeming populations of digestive organisms. Compost containing 3 to 5 percent biochar will likely be a higher quality premium fertilizer with more nutrients, better physical properties, and more vigorous, healthy microbial communities.
Biochar as Feed Supplement
Farmers who add biochar to litter soon notice birds peck at bits of char. They deliberately eat char — an intentional behavior.
Substantial data on four continents consistently reveal biochar as feed additive provides direct benefits to livestock.
At the University of Georgia, Dr. Casey Ritz began researching adding char to poultry bedding to control ammonia in 2007. He showed it cuts ammonia outgassing by converting it to stable ammonium. Ritz wondered if he could do this inside a chicken.
“We must stop ammonia before it’s made, instead of trying to mitigate it after it’s emitted,” said Ritz. “Char is a strategy with a good chance of success.”
Ritz fed chickens feed with 3 percent activated carbon added, while another group received normal feed with no char. Ritz found significant drops in ammonia in manure from char-fed chickens compared to chickens fed regular feed.
One Missouri farmer who feeds his chickens char observed, “When dressing chickens, I examine their gizzard and craw. I see black bits of char used to grind food. In gizzards, they’re ground smooth, almost-oval, with round ends, shiny, like river stone. So, biochar is introduced before intestinal digestion — like they chew food with charcoal teeth. Nutrient absorption starts immediately.”
He adds, with emphasis, “No ammonia smell — or any other smell, for that matter!”
The small, polished black balls form by abrasion with pebbles and food particles in the gizzard. Very fine carbon powder ground off bits of char is a catalyst to improve digestive efficiency. This benefit is both chemical and biological: it increases ion adsorption and transport while improving microbe function so the birds hardly excrete nitrogen as waste ammonia at all. Instead, nitrogen is now more fully metabolized into amino acids, which then can become proteins. Thus, birds exhibit better weight gain and growth.
Chicken feed is usually light brown, but char turns it black. Happily, the color doesn’t bother chickens. Char also changes manure color.
Charred carbon has no nutrient value for animals. Scientists say it is “only a filler” in feed, but that label is misleading, and at the least, understates char’s significant roles. As in soil, char provides essential services beyond being a nutrient source.
Biochar is a catalyst that brings essential elements, especially charged ions, together to encourage their reaction, but biochar itself remains largely unchanged by these reactions. Biochar provides sheltered spaces and selective surfaces for ions and microbes to assemble and interact.
Biochar is also a catalyst to facilitate populations of microbes. Many bacteria, fungi and other simple life forms prefer biochar as habitat, and take up residence in char micropores. Feeding biochar stimulates beneficial bacteria in the GI tract to strengthen digestion and immunity. Biochar can increase nutrient adsorption, retention and transport to improve the liver-intestine circuit.
Biochar’s probiotic benefits improve if char is pre-inoculated with digestive microbes. Thus, a wise way to use char is as a substrate to culture, transport and deploy diverse, complex microbe communities. A fully probiotic approach must adapt to unique conditions and needs. A microbe culture for seed planting is different than for compost tea, or cooking compost, or foliar feeding spray, or planting trees and each must be modified to meet each specialized environment and purpose.
Biochar promotes digestion, improves feed efficiency, and thus, energy gained from feed. Toxins are efficiently bound to biochar, mitigating adverse effects on the digestive system and intestinal flora. Health and vitality of animals also improves, as will meat and egg production. With animals’ immune systems stabilized, infection risks from pathogens decrease.
Scientific experiments attempt to determine how much char to add to poultry feed for optimum effects, but most often, char is raw, and is not pre-charged with minerals or pre-inoculated with microbes. Dr. Ritz’s best guess, based on experiments to figure a final formulation, is 1 or 2 percent of feed. His results align closely with those from Asia, Europe, Australia and India.
Wider adoption of this old substance for this new use in farming is encumbered by three major obstacles:
- Equipment and businesses are needed to produce and sell affordable biochar for poultry producers as a feed additive.
- U.S. FDA, USDA, organic certification agents, most states and regulatory bodies must review and approve char as a feed additive. Activated carbon is already approved for human use.
We need to develop formulations of biochar with minerals, microbes, metabolites and other nutrients as well as protocols for use in varied farm operations and crops.
Converting Litter to Bioenergy
Not just plant biomass can be converted to char; manures can be dried, then burned or baked into biocarbon. Developing activated carbons and char from broiler litter is very effective to reduce waste volume and treat waste emissions from production, storage and land application of litter.
Mississippi State researchers compared char made from poultry litter with commercial activated carbon made from coal for air purification. The poultry litter was mostly pine shavings, plus the poop. Lab results suggest char from litter performs as good as or slightly better than the commercial product.
This reduces the need to use high-value feedstocks or hard-to-harvest sources to make biochar. Rather, this allows farmers to convert an abundant on-farm resource — manure — into assorted valuable products, starting with bioenergy and biochar for soil.
USDA researchers recently found that charred poultry manure is extremely effective to selectively adsorp heavy metals, such as mercury, lead, cadmium, etc. Scientists now speculate about creating “designer biochars” tailored for specialized uses.
CHPB: Combined Heat, Power & Biochar
Carbonizing manure also yields heat and can produce syngas and biooil for on-farm power and biofuel. Gasifiers burn biomass to generate heat as well as biochar. But baking biomass by pyrolysis (coking) allows extraction of useful gas and liquid biofuels. These are well-developed technologies, but must be adapted to make low-temperature biochars for soil.
Most poultry barns are heated in winter and early spring, and many farms burn propane to produce that heat. Two problems: burning propane produces excess moisture, and imported fossil fuel is expensive. A chicken producer typically spends at least $20,000 each winter on propane heat.
An alternate approach is heaters that burn biomass and yield biochar, as by-product, instead of oxide ash. Three immediate, abundant, cheap farm feedstocks are cornstalks, manure and sawdust. Controlled combustion technology can capture 20 to 50 percent of biomass carbon as biochar. By restricting airflow and controlling time and temperature, farms can cut costs for off-farm fuels and fertilizers by making on-farm energy, soil amendment, litter additive, feed supplement and water purifier.
In Wardensville, West Virginia, third-generation poultry farmer Josh Frye raises 800,000 chicks a year. To maintain production in winter, he burned propane to heat his barn. A friend suggested a biomass gasifier could extract energy from poultry manure. Frye learned this also yields biochar, a non-odorous, dry soil conditioner and fertilizer.
For gasifier technology to meet his needs, Josh selected a fixed-bed gasifier built by Coaltec in Illinois, U.S. sales representative for Westside Energies of Canada. They helped him apply for grants to purchase and install a $1,000,000 unit. A 30-by-50-foot fixed bed gasifier installed in March 2007 burns at lower temperature to produce biochar and heat. Maximum feed rate is 1,000 pounds per hour, to yield 5 million BTU of heat, burning 12 tons of litter a day to produce 3 to 4 tons of char.
Frye’s gasifier began operating in 2009, producing high-quality biochar and fossil fuel-free heat. He sold his first biochar ton at net price $480 a ton to a New Jersey farmer to test on corn and soybeans. A South Carolina farm is testing the char on pharmaceutical grapes. With IBI leaders Johannes Lehmann and Stephen Joseph, Frye optimized his gasifier to make char rich in phosphorus and potassium. Test burns range from P 1.7-3.2 percent and K at 5.4-9.6 percent.
The first year of test burns produced 30 tons of biochar and saved 4,000 gallons of propane. Eventually, Frye expects to cut propane consumption by more than 80 percent. He also wants to use gasifier heat in the summer to run a chiller to cool poultry barns.
Frye’s annual production of 125 to 600 tons of poultry litter yields 25 to 120 tons of biochar. His gasifier-produced biochar has a 10 to 34 percent carbon content. Carbon content largely depends on manure moisture content. Lower moisture yields higher carbon biochar.
“I feel I’m making a real contribution to the ag world,” said Frye. “Converting a raw waste to stable carbon-rich biochar is great.” In 2009, the West Virginia Department of Environmental Protection awarded Frye the first-ever “Clean Energy Award” for his poultry litter gasification.
In Columbia, Missouri, Phil Blom of TerraChar works with Roger Reed, a combustion engineer, to install furnaces that burn sawdust into biochar to heat a boiler and heat exchanger. Reed adapted his sawdust burner to restrict air supply and make fine-texture biochar instead of ash. Roger’s high-efficiency, automated, low maintenance, small-scale gasifier uses air to move sawdust through a combustion zone and can be adjusted for other feedstocks such as cornstover, shavings or pellets.
These burner-boiler systems are installed in barns to create hot water and deliver radiant heat. This eliminates excess moisture from burning propane. Sawdust biochar is then mixed with litter to mitigate ammonia and other odorous gases and eventually ends up in soil as nutrient-rich, composted manure.
The current system they are building will produce 2.5 million BTUs of radiant heat per hour to heat two poultry barns. The equipment will consume 300 tons of biochar a year from 1,500 tons of sawdust biomass. In addition, the new system will send excess heat from the burner-boiler to a steam-driven 60 kilowatt per hour electric generator. The farmer will save up to $2,000 per month in electric power expense in addition to savings from avoided propane expense.
David Yarrow has taught and organized about building sustainable food systems in the Northeast United States for more than 30 years. He can be reached at email@example.com. For more information visit www.dyarrow.org and www.carbonnegative.us
David Yarrow, TERRA: 573-818-4148, firstname.lastname@example.org, www.dyarrow. org/CarbonSmart
Phil Blom, Terra Char: 151 Dripping Spring Road, Columbia, MO 65202, 573-489-8929, email@example.com, www.terra-char.com
Josh Frye: PO Box 218, Wardensville, WV 26851, 540-550-8856, firstname.lastname@example.org, www.fryepoultry.com
Hans Peter-Schmidt: farmer and researcher, Ithaka Institute, Switzerland, www.ithaka-institut.org
Casey Ritz, Ph.D.: Poultry Science, UGA, Athens, GA 30602; 706-542- 9139, email@example.com, poultry.uga.edu/personnel/ritz.htm
Kari Fitzmorris Brisolara, ScD: Environmental and Occupational Health, Louisiana State University, School of Public Health, 2020 Gravier Street, New Orleans, LA; firstname.lastname@example.org
Dana Miles, Ph.D.: USDA-ARS-Mississippi State, P.O. Box 5367, Mississippi State, MS 39762; email@example.com
Isabel M. Lima, Ph.D.: USDA-ARS-SRRC, P.O. Box 19687, New Orleans, LA 70179; firstname.lastname@example.org resources
This article appears in the March 2015 issue of Acres U.S.A.