sign in sign up
<<
Home , Rainforest

Special Report : A Game-Changer for

By Dave Story

Everything old is “Terra preta was discovered in the 1950s by Dutch new again. That certainly holds true scientist Wim Sombroek in the . It still cov- for biochar, a type of first ers 10 percent of the . Similar sites have been produced and used in the Amazon found in , Peru, Benin and in West .” basin centuries ago to make agri- Over the past 10 years, researchers have been investigating cultural land more fertile. Biochar terra preta, now called biochar, as an agricultural resource. results from heating waste, They have been interested not only in its value for plant culti- or , at high temperatures vation but also for its potential to address urgent environmen- in little or no . The process, tal issues, including change. Typically when biomass called pyrolysis, also takes place in decomposes or burns, virtually all of the carbon stored in naturally occurring fires resulting the plant is released into the atmosphere as , a from lightning strikes. Not only does Dave Story greenhouse gas that contributes to global warming. But when biochar help soils retain nutrients and Bartlett Experts biochar is produced, roughly half of the plant’s carbon is moisture, but it remains retained as stable carbon effective in the soil for in the biochar. The other hundreds of years – all half is released as of which means it can gases, which can be used help you better and more as an energy source. efficiently protect the This biochar cycle health of your clients’ puts carbon from the . atmosphere back into the , puts it to posi- Ancient yet modern tive use in the soil and As the nonprofit increases the amount of U.S. Biochar Initiative time it stays there. explains, “biochar has been created and used Moisture Management by humans in traditional and Nutrient Storage agricultural practices in So why is biochar the Amazon Basin of such a valuable soil for more amendment? According than 2,500 years. Dark, to Hugh McLaughlin, charcoal-rich soil (known Ph.D., P.E., a chemical as terra preta, or black engineer who has been an earth) supported produc- advisor to the nonprofit tive farms in areas that International Biochar previously had poor and, Initiative and is director in some places, toxic of biocarbon research at soils. Alterna Biocarbon Inc., 48 The Contractor January 2013 Biochar: This is the first of two articles on biochar, a potent soil amendment for A Game-Changer for Soils urban and suburban landscapes.

the principle contribution of biochar is “a combi- nation of moisture management and providing a way to store microbial food and plant fertilizer. When there is an excess of water, food and fertil- izer, biochar stores them. When there is a defi- ciency, it slowly releases them back into the soil, where the plant or microbes can take advantage of them.” Dr. McLaughlin explains what he calls a subtle but critical concept about the symbiotic relationship between and soil microbes. In traditional growing practices, a plant receives its moisture from the soil. Through it combines the water with carbon dioxide to produce sugar that it uses to grow. It also exports some of that sugar through its roots to feed soil microbes. The microbes in turn provide nutrients – both macronutrients and micronutrients – back to the plant. Adding a nitrogen-phosphorous-potassium fertilizer removes the plant’s need to work with the microbes. Since it receives needed macronu- trients from the fertilizer, the plant stops send- ing sugar to the microbes and uses all of it to grow. But there’s a problem: the plant no longer receives a balanced diet because the microbes (continued on page 50) The Landscape Contractor 49 January 2013 Special Report

(continued from page 49) liquid in it. When you place it in a pail water and fertilizers is particularly valu- no longer produce the micronutrients it of water, water flows in and takes up the able is the urban tree pit. Bartlett Tree needs. And that can impact its long-term voids. Experts and The Morton Arboretum are plant health. Biochar is highly adsorbant. It researching biochar in those and other Biochar reduces the need for NPK adsorbs humic acid, which is a food urban and suburban applications. (More fertilizers, cultivates beneficial soil source for soil microbes. And humic acid on that in the second article of this microbes and, because the plant has bet- adsorbs fertilizers, keeping them from series next month.) ter overall health and is less susceptible leaching out of the soil. to pests, reduces the need for pesticides. Biochar is also highly adsorbant of All biochars are not water. As it turns out, in conditions with created equal Like a wet sponge greater than 60 percent relative humidity, So let’s say you would like to use What makes this possible is biochar’s biochar fills all its adsorption sites with biochar on your clients’ properties. You ability to adsorb, says Dr. McLaughlin. water. Below 40 percent, it releases all can just buy a bag and start applying it Not to be confused with absorption, the water. That makes it an enormous to the soil, right? You could, but you adsorption involves voids in one sub- stabilizer of relative humidity in soils, would need to do your due diligence stance taking up another substance. which means less watering. first to know what you’re getting. He uses the example of a wet sponge: One growing situation in which Different biochars have different qualities. When you wring it out, you remove the biochar’s ability to reduce the need for In 2009, the International Biochar

50 The Landscape Contractor January 2013 Initiative began developing standards Levine, cofounder and vice president char was created and packaged, there for biochar. Its initial focus has been on of Biochar Solutions Inc. and special could be a lot of water in it. “While ensuring that biochar products are safe projects lead for Biochar Now, which that’s not a bad thing, it’s probably not and contain no toxins. The next step nec- makes Bartlett Tree Experts’ Premium worth buying for the price. The label essary, says Dr. McLaughlin and others Landscape Biochar, says, “The way we ought to admit that when you’re holding in the industry, is labeling that describes achieve standards as a company is to this nice heavy bag of char, it’s mostly measurable characteristics of the biochar measure materials coming in and going water.” that relate to quality and performance, out, and we track that data. In our equip- Another component to look for is more along the lines of nutritional label- ment we’re tracking data multiple times ash. It may include the traditional inor- ing for foods. This is especially impor- per second in the process … I run the ganic NPK plant fertilizers, which you tant since different sources of biomass statistics on those numbers and charac- may already be adding to the soil sepa- and different production methods and terize the biochar at a third-party lab.” rately from the char. ‘It’s not practical to equipment can dramatically affect the supply your fertilizer needs by providing quality and properties of the biochar The informed buyer a lot of char,” says Dr. McLaughlin. produced. So what should consumers of bio- “Most clean chars, made from woody or Some biochar producers run their char watch for? Water, for one. “When pure biomass, are only about 1 percent own tests and/or send their product you look at a bag of char,” says Dr. to 2 percent ash.” to third-party labs for analysis. Jonah McLaughlin, “depending on how that (continued on page 52)

The Landscape Contractor 51 January 2013 Special Report

(continued from page 51) childhood nutrition impacts the health of a 40-year-old,” he In addition to water and ash content, the big properties to says. “So the characterization of a particle of biochar is less watch for are bulk density and adsorption capacity. Biochar important than how those qualities will affect the plant. opens up soil and aerates it. Bulk density is important in pre- “Biochar characterization is still a conversation of what dicting the extent to which it will do that, and lower bulk den- exactly is that biochar particle. But what does that mean to the sities are better. If the soil is full of clay, lower-density char end user? The biochar community has not in the past under- will be help prevent the clay from sealing up. With sandy soil, stood that need.” which has plenty of drainage and aeration, adsorption capac- He’s optimistic, though, pointing out that the conversa- ity is more important – a higher adsorption capacity can help tion about getting biochar production into compliance began retain the soil moisture. a mere five years ago. “That’s fast for creating standards in So what’s a biochar buyer to do? Mr. Levine suggests what could be a 30-year process,” he says. going online and looking for a company that has the right types of credentials. “It will be a company that has people Dave Story is a certified , a certified tree risk who have been involved in the industry for several years,” he assessor and local manager for Bartlett Tree Experts says. “It will have engineers, business professionals. It will (bartlett.com). Founded in 1907, Bartlett is a research-driven, be testing with third-party labs, government agencies. It will family-owned and operated tree care company with local have case studies in the ground.” offices in Northbrook, Bolingbrook, Lake Barrington and Chicago. Predicting performance Beyond characterizing biochar, what will be even more valuable to the landscape industry will be the ability to pro- vide predictors for how the biochar will perform. Mr. Levine uses the analogy of childhood nutrition. “It’s hard to say how

52 The Landscape Contractor January 2013