Tiered Approach for Assessing the Effective and Safe Applicability of Beech Wood Biochar for Soil Improvement

The soil degradation processes may cause long-term serious problems in various areas of life on Earth, thus mitigation of these processes by environmental-friendly, innovative soil protection methods is necessary. Biochar produced from organic wastes or by-products by pyrolysis may have several positive properties as additive in soil improvement technologies. In our complex research applying a tiered approach we assessed the main properties of a beech-wood biochar produced from a high volume by-product of a food industry technology. Then we studied in 4-months microcosm experiments the applicability of this biochar as amendment mixed into an acidic, degraded sandy soil. In addition, to forecast the long-term effects of the biochar, artificial physical and biological aging experiments were conducted. Based on the results, the beech-wood biochar was able to shift the acidic pH of the soil to the alkaline range and the electric conductivity of the soil increased with incremental biochar doses. Biochar addition significantly increased the microbial activity, as well. The results had clearly shown that during the mid-term experiment not even the highest biochar dose (15%) had inhibitive effect, but it rather improved several soil parameters. Furthermore, the biochar had positive effect on the soil water holding capacity, and the available soil nutrient and organic matter content. The results of the aging experiments generally showed also favourable effects and demonstrated that the aging-mediated changes differed according to the soil types. Therefore, we have concluded that biochar application requires a char by char and soil by soil testing prior to field application.