Biochar amendment increases soil microbial biomass and plant growth and suppresses Fusarium wilt in tomato

The use of biochar as a means of mitigating climate change and improving soil physical and chemical characteristics has been extensively studied over the last two decades. However, the effects of biochar on the soil microbiota and plant diseases, especially those caused by soilborne plant pathogens, have received little attention and are poorly understood. The objectives of this study were to evaluate the effects of biochar at different concentrations incorporated into two soils on the control of Fusarium wilt, tomato development and soil microbial activity. The severity of Fusarium wilt and microbial activities (microbial biomass nitrogen and alkaline phosphatase) were inversely proportional to the concentrations (0 to 5%, v/v) of biochar incorporated into the soil. The fresh root and dry shoot masses and stem diameter measures increased with the increase in biochar concentration. Biochar aqueous extract did not affect Fusarium mycelial growth, but microconidial germination was reduced with the increase in the concentration of biochar aqueous extract. The biochar used in the present study has the potential to increase soil microbial biomass, promote plant growth and reduce the severity of tomato Fusarium wilt.