BIOCHAR: Have you ever gotten ready to Why add to soil? almost half the carbon being light your charcoal for the summer Slash and burn agriculture released. The second, and slightly barbecue and thought, “I bet is a common practice in South improved technique, is to use this stuff would be great for my America and has resulted in the a kiln, which serves the same garden soil.” accumulation of biochar in farm purpose as the pits but is more If you have, you’re not alone! soils. The decades of slash and efficient with less pollutants For the last 50 years scientists burn farming resulted in the added to the atmosphere. have been interested in using continual buildup of biochar in The third and preferred biological-charcoal, aka biochar, infertile soils producing unique method is through pyrolysis, to improve soil. More importantly, regions of fertile Amazonian Terra which is essentially a waste-free farmers have been modifying Preta soils. system. Biomass pyrolysis was soil with biochar for thousands These soils are rich, black used initially to produce chemical of years. The question is, does soils, high in organic matter energy. The process creates biochar improve soil health and and fertility. While slash and three products: non-condensable crop yields or is it an old wives’ burn farming has many negative gases, combustible bio-oil, and tale? consequences, the discovery of biochar. these Amazonian Terra Preta soils The gases are captured and Defining biochar in 1969 sparked scientific interest combusted to re-heat the system, Biochar is made from heating in biochar as a soil amendment. the bio-oil is used as fuel, and organic materials, like dead trees, In the last 20 years, the interest historically biochar was the construction waste, poultry in carbon capture has further waste product. Biomass pyrolysis litter, and wheat straw, at high increased interest in using biochar was replaced by coal and then temperatures (from 550-1,290 as a soil amendment. fossil fuels as a cheaper energy F) under anaerobic (no oxygen) alternative in the 1800s. Biomass conditions resulting in a carbon- How biochar is made pyrolysis is seeing renewed rich, porous biochar product. There are three main ways popularity with increased interest The resulting biochar is different to make biochar. The first, and in renewable fuel sources and depending on the source material oldest, is through the slow carbon capture. But now, instead and how it was heated and burning of piles of wood in pits of being a waste product, biochar handled. with limited oxygen. This process is one of the high value products results in a lot of smoke and of the process.
12 BARNYARDS & BACKYARDS What is it and what does it do? Does biochar added to soil do Feedstock type, quality, Claim 1: Biochar sequesters any good? moisture, production method, and carbon in the soil forever. A quick internet search post-production handling impact YES, but also NO. Producing results in a plethora of biochar the type and qualities of the biochar does capture carbon and claims, including combating biochar. contains it in a stable form that climate change, immobilizing soil The application rate of biochar can help reduce atmospheric pollutants, increasing soil fertility, to the soil has varying effects, carbon. Biological organisms are improving crop performance, and with too little being ineffective made up of carbon. When they more! and too much being toxic. As if die, that carbon decomposes and There is some truth to the that weren’t complicated enough, is added to the atmosphere and benefits of biochar added to soil, the type of biochar, soil type, soil system. When biochar but unfortunately not all biochar is climate conditions, and crop type is made, the carbon is created equal, and using biochar all factor into the equation. What transformed and has the is not as straightforward as do we know about using biochar using standard fertilizer or even as a soil amendment? compost.
SPRING 2019 13 potential to remain in a stable increase cation exchange capacity Currently, large applications state for a long time before and change soil pH, which affects of biochar to improve crop yields returning to the atmosphere. which nutrients are available to are not economically viable. However, the pit and kiln methods crops. However, not all biochar Even at a very low application still contribute significant pollution in all soil has the same impact. rate of 1 percent per volume, to the atmosphere. Additionally, Some changes in available soil you would need to apply about the amount of stable carbon nutrients can have toxic effects 8 cubic yards/acre, which would produced and life expectancy on plant growth, and our ability to cost an estimated $2,000. Such of biochar in the soil depends predict the effect of biochar is still low amounts are unlikely to have on source material, production limited. positive effects on crop yields. methods, and post-process Biochar can also change the But there is work being done handling. So biochar does physical properties of soils. Its on designer biochars that could sequester carbon (sometimes for porous structure increases water be produced to treat specific a very long time), but not forever. holding capacity and how fast soil issues. We may find the Claim 2: Biochar “sucks up” water can infiltrate. Both of these economics around specialized pollution from the soil. improvements would be very uses are more reasonable as the YES! Well, some pollution. beneficial to Wyoming agriculture. understanding of designer biochar Biochar has been found An item of concern is how much increases. to immobilize certain soil biochar needs to be added contaminants when used for to change the water holding Take home message site clean-up. Once again, not all capacity and if that amount is in Biochar still shows great Q biochar has the same absorption balance with what is needed for potential for capturing carbon and ability, and there are still many good crop nutrition. Numerous storing it in the soil to improve questions surrounding how studies document yield increases farm ground. Unfortunately, and when to use it. There is from biochar soil amendments, there is still a lot to learn about great potential to use biochar but there are also many studies production and use of biochar as to help restore soils that have that find no benefit or even a soil amendment to be confident been contaminated return to reduced yields with biochar. in the effect it will have on soil productivity. properties and crop performance. Claim 3: Biochar improves Does biochar make CENTS? There is strong evidence biochar soil fertility and increases crop The complete economic is a beneficial soil amendment, yields. picture for biochar use for soil and and we are working hard to MAYBE! The effect of biochar crop improvement is complex. fully understand and unlock on soil fertility is dependent The economic analysis starts its potential. The University not only on the biochar, but with production of feedstocks, of Wyoming has multiple also on the soil type and includes transportation to and researchers exploring how we can nutrients of interest. Biochar from production plants, the best use biochar in the state. feedstock determines nutrients cost of production, the value of in the biochar. Feedstocks like co-products, storage and handling Carrie Eberle is the agronomy and poultry litter typically produce costs, and ends with assessment cropping systems specialist with the biochar with higher nitrogen, of soil improvement, crop yield University of Wyoming Extension. She phosphorous, and potassium gains, carbon credits, and land can be reached at (307) 837-2000 or at than biochar produced from restoration value. [email protected]. wood. Biochar has been found to
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