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32 W i n e s & V i n e s s e p t e m b e r 2 0 1 4 g r a p e g r o w i n g I n the past several years I have been hearing more and reading more about the use of biochar as a soil amendment. Promoters of its use present an impres- sive list of what biochar can do for our soils and greenhouse gas problems, including: improved water-holding capacity, improved nutrient-holding capacity, provid- ing a favorable habitat for soil microbes and long-term carbon sequestration. What is biochar? Biochar is a fine-grained, highly porous, charcoal-like material that has a high sur- face area per unit volume and low amounts of residual resins, making it an ideal soil amendment. Its properties differ significantly from those of charcoal, which has undesirable tars, resins and polycyclic aromatic hydro- carbons that are toxic to plants. Furthermore, char- coal has less adsorption capabilities than biochar. Technically, biochar is the carbon-rich product of the carbonization of biomass using pyrolysis. (Pyrolysis is the exposure of organic matter such as wood, leaves, nutshells or manure to temperatures around 300º–700º C, under a limited supply or complete absence of oxy- gen.) Energy products in the form of gas or oil are also produced during biochar produc- tion and can be recovered for later use or burned during the process to produce heat. The high surface area and porosity of bio- char allow it to adsorb and retain nutrients and water as well as provide habitat for microorganisms. While raw organic materi- als and compost supply nutrients to plants when incorporated into the soil, biochar plays the role of a catalyst through its adsorption properties, enhancing plant uptake of nutrients and water. Biochar is a relatively new term for a sub- stance that is very old. Producing biochar is a 2,000-year-old practice, and it is found in soils throughout the world as a result of vegetation fires and historic soil-manage- ment practices. The North American prairie west of the Mississippi River and east of the Rocky Mountains contains biochar, for example, resulting from forest and grass- land fires. Probably the best-known example of bio- char being deliberately added to soils is in the Amazon basin of Brazil, where pre- Columbian people from about 450 BC to 950 AD added a mixture of biochar, bone and manure to relatively nutrient-poor Amazonian soils over time to develop very dark, fertile soil that can be more than 6 feet deep. These Terra Preta ("dark earth") soils exhibit high microbial activity and are resis- tant to nutrient leaching, a significant prob- lem in Amazonian soils. The use of biochar also has a long history in parts of Asia—particularly Japan and Korea. Biochar can vary quite a lot in makeup due to the type of feedstock and methods of pyrolysis used to produce it. In fact, one of the challenges of figuring out how to effec- tively use biochar is due to the great varia- tion in the product. Production practices can range from a backyard operation to specially designed equipment in a factory. To meet this challenge, the International Biochar Initia- tive (IBI) led a stakeholder process to define Use of Biochar in Vineyards Highlights • Biochar has shown great potential to increase soil quality through improved tilth, water- and nutrient-holding capacity and providing habitat for soil microbes. • Biochar also has the potential to sequester a significant amount of carbon for very long periods of time. • Biochar varies widely in its properties due to the wide variation of feedstock and production methods. • The current price of biochar makes it difficult to economically justify as a soil amendment for many vineyards. Vineyard View C L I F F O H M A R T CoolTerra built this state-of-the-art biochar production pilot plant in Camarillo, Calif. International studies have shown that biochar has a positive effect on soil quality.