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What can you tell me about biochar?

Answer: Biochar was initially linked to the exploration and archeological study of early human settlement and soils. These early studies of soils being enriched from what appears to be the deliberate mixing of burned biomass in soils around human settlements helped spark more recent interest in biochar. These deposits of enriched soils, known as terra preta in the Amazon region of South America, have a fascinating history of scientific study of their own.More current studies of biochar are focused on its role in a growing demand for biomass-based energy sources that can mitigate greenhouse gas emissions and slow climate change. For more information about bioenergy, see the ATTRA publication An Introduction to Bioenergy: Feedstocks, Processes and Products, available at https://attra.ncat.org/attra-pub/summaries/summary.php?pub=342. In addition, biochar has the potential to enhance soil quality and soil carbon sequestration. For more information about carbon sequestration, see the ATTRA publication Agriculture, Climate Change and Carbon Sequestration, available at https://attra.ncat.org/attra-pub/summaries/summary.php?pub=297. A secondary source of interest in biochar comes from the growing need to develop low-cost and healthier biomass-fueled stove technology. So, what is biochar? The definition of biochar is more about its creation and intended application rather than what it is composed of. Both charcoal and biochar are produced through an energy conversion process called pyrolysis, which is essentially the heating of biomass in the complete or near absence of oxygen. Pyrolysis of biomass produces char, oils and gases. The amount of these materials produced depends on processing conditions. What makes biochar different from charcoal is that the biochar product is created for use as a soil amendment. Biochar can be produced from a variety of biomass feedstocks, but is generally designated as biochar only if it produces a useable co-product for soil improvement. The oils and gases from pyrolysis can be used for energy production. The biochar and energy created can provide a carbon-negative energy source and a useable co-product for soil improvement. Carbon negative renewable fuels are discussed later in this publication. However, not all biochars are created equal. The efficiency and effectiveness of the process of its creation and use can vary and the specific biomass sources used can affect the characterization and usability of the biochar.Complex ongoing research is striving for a more uniform and standard biochar that will limit potential environmental problems associated with biochar production and application to soils. Creating a standardization of biochars may make it possible for people who buy biochar to depend on uniform attributes. Issues such as what should be the ideal moisture and ash content of standard biochar are relatively easy to measure and standardize, but tests for metals and alkalinity are not. Some of the attributes that might be expected from biochars can go beyond just physical characteristics to issues of whether the feedstock used in its creation was from a renewable feedstock, whether its production reduced greenhouse gas emissions and whether the biochar can improve soil quality in a reliable way.Among its important benefits to farmers and ranchers, biochar can provide increased soil fertility, moisture retention, and soil pH balancing.To learn much more about this topic, consult the ATTRA publication Biochar and Sustainable Agriculture, available at https://attra.ncat.org/attra-pub/summaries/summary.php?pub=322. This publication reviews the current research and issues surrounding the production and use of this emerging biomass energy technology and explores how biochar can contribute to sustainable agriculture.