Biochar derived from pyrolysis of agricultural biomass wastes and by-products is increasingly recognized as a multifunctional material for agricultural and environmental applications. The aim of this work was to evaluate the influence of pyrolysis temperature on the chemical changes of biochar. Biochars were prepared under different temperatures (450°C, 550°C, 650 °C and 750 °C) using four different agricultural biomass wastes and by-products, namely sugarcane residue, sugarcane bagasse, rice residue, and rice husk. Increasing the pyrolysis temperature decreased the yield of biochar, while it’s C/N ratio was increased. Concentration of elements in biochar was increased with increasing temperature. In addition, all the biochars produced from the above sources were characterized by Py-GC/MS. Environmental impacts of biochar application in soils on greenhouse gas emission and pesticide sorption-desorption were evaluated. Implications of these results will be discussed.