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Biochar in a forest
Biochar permanently sequesters carbon and returns nutrients to the soil to bolster soil microbial activity. Credit: Tracy Robillard, NRCS Oregon

Biochar has been used over the years throughout the world as a soil amendment, but research on its properties and potential benefits have recently gained the attention of foresters and agricultural producers. Biochar is a stable solid, rich in carbon that is made from organic waste material or biomass that is partially combusted in the presence of limited oxygen. The qualities that make up biochar vary depending upon the material that it comes from (feedstocks; i.e., timber slash, corn stalks, manure, etc.) and the temperature at which combustion occurs. The various materials and methods to produce biochar result in a wide variety of chemical and physical properties across biochar products. To understand the properties of biochar, a user should know 1) what it was made from (i.e. the feedstock), and 2) the temperature at which it was made (i.e. 300-700C).

A common attribute among all types of biochar is the primary ingredient: a recalcitrant carbon that can persist in soils for years or decades, and even millennia. Biochar can be used as a soil amendment by itself, or it can be blended with other soil amendments to address a wide range of environmental, agricultural, and forestry challenges. Research underway by the USDA Forest Service, USDA Agricultural Research Service, the Environmental Protection Agency, and others will provide insight into how effective biochar is at binding with heavy metals and chemicals from agricultural and road runoff for the purpose of environmental remediation. Applications of biochar include improving soil health, raising soil pH, remediating polluted soils, sequestering carbon, lowering greenhouse gas emissions, and improving soil moisture. Know your soil amendment goal(s), to determine which biochars are best to achieve your goals.

Biochar resources: