Pyrolysing agricultural crop residues and other biomass constitutes a newer method of transforming often difficult, waste materials into a novel type of soil amendment/additive. Simultaneously, this process also makes it possible to exploit part of the energy released in the agricultural production. Biochar, viewed as the solid product of biomass pyrolysis, is a remarkable, porous material, rich in carbon. Two agricultural crop residues, such as wheat and barley straw, were selected for the experimental studies. The results indicate that the practical temperature for the production of biochar from the two explored materials occurs in the vicinity of 600 °C. Starting at this temperature, the biochar produced complies safely with the principal European Biochar Certificate standards (EBC 2012). Thus, for the wheat straw and barley straw – originated char, the content of the carbon amounts to 67.2 and 67.0 mass %, the atomic ratio H : C is as large as 0.032 and 0.026, and the specific surface area amounts to 217 and 201 m²·g^–1, respectively.