ABSTRACT
Despite the recent interest in the use of biochar in agriculture, its current use is still limited. In terms of market development, if biochar can be used as a soil amendment to improve soil quality and to increase crop production, this will increase its appeal (Day et al, 2004). In this regard, an obvious positive attribute of biochar is its nutrient value, supplied either directly by providing nutrients to plants or indirectly by improving soil quality, with consequent improvement in the efficiency of fertilizer use. As a measure of the direct nutrient value of biochars, it is not the total content but, rather, the availability of the nutrient that is an important consideration.The total content of nutrients is not an appropriate indicator of the availability of nutrients as only a fraction of the total content is immediately available or is readily converted to available forms for uptake by plants (Keeney, 1982).
