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What is biochar?

27 Mar 2019
New initiative to boost use of ‘game-changing’ soil amendment

By Alice LeBlanc, economist and independent consultant based in New York. She has worked in corporate and NGO settings for more than 25 years to promote market-based and land-use sector solutions to climate change.

Climate Smart Agriculture (CSA) is increasingly recognized for its contributions to improved agricultural productivity and soil health, as well as to addressing environmental problems such as water pollution, water scarcity and, most importantly, climate change, primarily through carbon sequestration and increased resilience. International conferences are drawing attention to CSA and its role in fulfilling national pledges to meet the goals of Regreening Africa, the Bonn Challenge and other country-led goals to restore soil and landscapes of millions of hectares.

Biochar, a biomass-based material produced by a process that mirrors charcoal production, has a primary application in its use as a soil amendment, with the intention to improve soil functions and to reduce emissions from biomass that would otherwise naturally degrade to greenhouse gases. It is recognized as a “game changer” in agro-ecology for addressing and reducing climate change causes and impacts and has been called the “Third Green Revolution.” Yet biochar remains relatively underutilized among CSA practices.

Added to the often-poor soils of the humid tropics, it sequesters carbon and significantly increases food yields. It alters the property of the soil to retain more water and nutrients, enabling legumes to fix atmospheric nitrogen more efficiently and attract microbes. When combined with natural fertilizer such as manure, it improves plant growth and resilience and can be a cost-effective way to increase soil health, boost crop production, use water more efficiently, decrease the need for inorganic fertilizer, capture atmospheric carbon dioxide and reduce emissions of other greenhouse gases.

Biochar production is a 2,000-year-old technique that requires heating biomass – often agricultural residue –with little or no oxygen, in turn driving off volatile gasses and leaving half of the carbon behind. Waste materials appropriate for biochar production include crop residues (both field and processing residues such as nut shells, fruit pits and bagasse); some invasive species; yard, food, and forestry wastes; and animal and human manures.

A biochar production area in Ethiopia. Alice LeBlanc, ASI

The heat or combustible gases emitted during the production process can be recovered to generate usable renewable energy, including liquid fuels, gases or electricity. In regions that rely on fire for food preparation, biochar is produced from individual biomass-fueled “stoves” where the heat generated is used for cooking. Larger production units or kilns can be used to produce biochar for a village. Mobile units can be used to collect and produce biochar from crop residues in fields. When biochar is produced on a larger scale, a combustible gas is produced that can be fed into a small electric generator to serve a micro-grid or larger generator to produce electricity. Biochar can also be used for remediation of toxic sites and for water filtration.

Using biochar in combination with planting perennial tree crops pulls more carbon dioxide out of the air, with the carbon stored in above-ground biomass and in root systems, which further contribute to soil health. Additionally, higher yields of marketable perennial crops resulting from biochar use and natural fertilizer can generate more revenue for communities.

For the past couple of years, I have worked along Tom Miles and Johannes Lehmann of the International Biochar Initiative (IBI); John Lewis of Terra Global Capital; Brando Crespi, vice-chair of Pro-Natura International; and Anne Hummer, former executive director of the Society of Conservation Biology to lay the foundation for a new NGO, the African Soil Initiative (ASI). ASI, which has been registered in the state of New York as a non-profit organization under the fiscal sponsorship of the IBI, aims to improve both crop and grazing soils and productivity across Sub-Saharan Africa by scaling up the smart use of biomass and nutrients, including production and use of biochar as a soil amendment and the planting of soil-enhancing trees with high-value crops, such as palm oil, coffee, cacao, shea butter, cashews and moringa.

ASI intends to work with a consortium of existing organizations that are already helping African farmers and pastoralists implement on-the-ground CSA practices and/or working on soil regeneration to introduce the use of biochar on a scale larger than the small research projects undertaken to date.

A farmer in Jimma, Ethiopia, who has seen the benefits of biochar. Alice LeBlanc, ASI

On a recent trip to Ethiopia, I visited a biochar pilot research project conducted at the University of Jimma in collaboration with Cornell University with funding from the McKnight Foundation. The project is evaluating the effectiveness of different formulas for making biochar and co-composting it with natural fertilizers, while helping several dozen farmers incorporate biochar in their fields.

Jimma is located on the Awetu River about 240 kilometers southwest of Addis Ababa, not far from the lakes of the Rift Valley. Milkyas Ahmed, a faculty member at the Agricultural College of the University of Jimma, gave me a tour of the small biochar production machines – akin to kilns or vats – where the biochar is produced and, nearby, of the vats where co-composting occurs. He also showed me the experimental plots where benefits of biochar are being measured by comparing crops grown with and without various co-composting formulas and the multi-cropped fields of the farmers who were using the biochar. In some cases, the farmers are producing the biochar themselves using a very low-cost method.

Farmers who participated in this pilot project have seen positive results in crop productivity. The research being conducted is measuring the benefits of various ways of producing, co-composting and using the biochar. Results should be available in the near future.

Following the Global Landscape Forum in Nairobi last year, I met with staff from Lewa, a privately-owned wildlife conservancy in Laikipia County in Kenya’s Rift Valley, and from the Northern Rangelands Trust (NRT). NRT  supports 39 community conservancies spanning approximately 42,000 square kilometers of dry grazing lands within northern and coastal Kenya. These conservancies are home to around 320,000 people from 18 different ethnic groups. Conversations with NRT, Lewa and IBI uncovered a mutual interest in exploring the production and use of biochar, in conjunction with the removal of woody invasive species that are creating problems on grazing lands within NRT member conservancies. Lewa expressed an interest in working with farmers living just outside the Conservancy borders to incorporate biochar in farming there.

Information gained from these two site visits underscores the importance of ASI’s overall goal of raising awareness of the benefits and cost-effectiveness of biochar combined with agroforestry in Africa by scaling up its production and use in different African regions and for a variety of project types.

Milkiyas Ahmed, a lecturer at Jimma University’s College of Agriculture, holds crop residue that will be turned into biochar. Alice LeBlanc, ASI

ASI’s website is currently under construction. Check back soon at www.africansoil.org. Until then, contact Alice LeBlanc at [email protected] or Tom Miles at [email protected] for more information.



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