Converting sugarcane and rice harvest residues to biochar being used as soil amendment could potentially improve soil conservation. In this study, fundamental properties of biochar produced from sugarcane and rice residues and their environmental functions were evaluated. Biochars were produced at 450oC and 750oC, respectively and were characterized for elemental, molecular and surface structural properties. In general, sugarcane and rice residue biochars exhibited different elemental and molecular compositions. Charring at high temperature decreased N and S contents but increased P, K, Ca, and Mg. Increasing temperature also caused the loss of the surface structures of biochar. Soil treated with either sugarcane leave or bagasse char enhanced the adsorption capacity of atrazine, a common herbicide used in sugarcane production.