Evaluation of physico-chemical properties of rice straw and rice husk-derived biochar

摘要

Biochar is widely recognized as an efficient tool for carbon sequestration and soil fertility. It is a co-product of pyrolysis of biomass like rice straw and rice husk, its qualities vary according to pyrolysis conditions but it mainly contains phosphorus and potassium. The carbon (C) content in biochar is stable, so it can be applied to soils for enlarging the C sink. The present study was carried out to evaluate the physico-chemical characterization of rice straw and rice husk-derived biochar. Locally available bio-wastes viz. rice straw and rice husk were used as raw materials to produce chars in slow pyrolysis (300 - 400°C) process. Two samples of feedstock from 5 development blocks of Jorhat district of Assam were collected, dried and pyrolysed for production of char for their physico-chemical properties. Percent moisture and ash content, bulk density, particle density and porosity of the biochars ranged from 3.38-4.91%, 13.17-24.97%, 0.629-0.729 g/cm~3,1.91-1.92 g/cm~3 and 61.54-67.25% respectively. Pore volume, particle size and specific surface area ranged from 0.83 to 1.05 mL, 326x153 to 350x209 and 89.40 to 121.48 whereas pH, EC, CEC and total Carbon varied from 7.74 to 9.46, 0.457 to 1.005 dsm-1,12.74 to 15.67 c mol (p+)/kg and 36.63 to 41.16% respectively. The rice straw-derived biochars had high alkalinity and high levels of available phosphorus compared to biochars derived from rice husk. So, it indicates that rice straw-derived biochar can potentially be applied as a fertilizer and soil amendment.