Biochar can improve soil productivity. The highest increase in total biomass and grain yield of wheat was obtained by rice husk biochar in low Cd soil which was about 25.6% and 34.0% higher compared to the CK (Table 3). Biochar amendments could improve crop yield by acting as a direct nutrient source and by improving soil pH, CEC, surface interactions, and so on53,54. In a pot experiment on wheat55, soil organic matter content was more effectively increased by application of rice husk biochar than rice straw or rice husk due to the recalcitrance of C-organic in rice husk biochar56,57 Rice husk biochar supplies soil nutrients especially some primary macroelements (et. potassium) and increase the fertility of the soil to increase crop yield. Moreover, it is worth mentioning that rice husk biochar is the richest source of Si that through pyrolysis can be increasing of solubility of Si58 and promotes plant growth40.
