Biochar is gained from pyrolysis of biomass. Addition of biochar to soil has been suggested as an effective strategy for soil improvement and soil remediation. The positive effects of biochar on soil quality arises among others from the increased of soil water holding capacity, pH, and nutrient content upon biochar amendment to soil. Porous structure and high carbon content makes biochar an efficient sorbent for pollutants resulting in their lower bioavailability and hazards. Changes in soil properties upon biochar addition may, however, potentially negatively impact soil organisms by affecting nutrient and vitamin bioavailability, pH shifts falling out of the pH optimum of organisms etc. These aspects of biochar in soil should be thoroughly investigated for a broad spectrum of organisms in order to optimize biochar usage as a soil improvement and remediation tool. The main goal is to explore and balance the primary (remediation) and secondary (negative side effects) of biochar particles on soil organisms.