Abstract

Biochar is one of the significant soil amendments. A lot of research has already done in the field of biochar. But very few studies have mentioned the effect of pyrolysis temperature on the plant growth. To the best of our knowledge we have not yet come across any systematic study elaborating the effect of various pyrolysis temperature of coconut husk biochar on seed germination and plant growth. Therefore, the experiment was conducted during 2019 to 20 at Institute of Chemical Technology, Mumbai, India to explore the effect of coconut husk biochar produced at various pyrolysis temperatures (300, 400, 500 and 600°C) individually and along with the nitrogen fertilizer (urea) on the growth of sorghum. Maximum biochar yield of 54.67 % was obtained at 300°C. The ash content, pH, and EC (electrical conductivity) of biochar significantly increased with increasing pyrolysis temperature, maximum ash content (31.4 %), pH (9.9) and EC (2.48 mS/cm) were observed at 600°C pyrolysis temperature. Bulk density and nitrogen concentration of biochar reduced with increasing pyrolysis temperature. Highest nitrogen concentration of 0.62% was detected in biochar produced at 300°C. Surface area of the biochar increased with an increase in the pyrolysis temperature giving a surface area of 213.91 m2/g at 600 °C pyrolysis temperature. The germination percentage was adversely affected by the use of biochar and nitrogen fertilizer combination treatment. Maximum shoot and root biomass of sorghum were obtained with the use of biochar produced at 300°C. Similarly, plant height, leaf area and stem diameter were significantly high in the treatment containing biochar obtained at 300°C pyrolysis temperature. Nevertheless, combining biochar and nitrogen fertilizer had no synergic and summative effect on sorghum growth. The findings of the present study thus demonstrate that biochar obtained at low pyrolysis temperature can be a practical approach to enhance crop biomass growth and possibly yield.