Rice-husk biochar potential to affect soil properties and vegetative stage of rice growth under different irrigation

Biochar is the carbon-rich material that obtained when organic materials are heated through pyrolysis process in a low or no oxygen available. While there are extensive researches on biochar, most of them use biochar produced from wood. Research on biochar produced from rice husk is still very limited. This study aims to analyze the physical and chemical properties of rice husk biochar and to investigate the effect of rice husk biochar application on soil properties and rice growth during vegetative stages under different water regimes. Outdoor pot experiments were carried out with three rates of biochar applications (0%, 2%, and 4% w/w) and three types of water regimes (dry, moist, and waterlogged) which were applied to loam soil and taken from paddy field. During 60 d of rice growing periods, soil moisture was monitored. At the end of the experiment, soil physical properties and rice growth parameters were analyzed. Results indicated that the commercial rice husk biochar produced at high temperature (> 600°C). Biochar application reduced soil bulk density and increased total porosity and hydraulic conductivity. The effects on water retention characteristics were difficult to conclude. However, the average water content during growing period was higher in biochar-amended soils than the unamended control. Biochar application also resulted in improvement of rice growth during the vegetative stage. This study is a small-scale and short-term study. Thus, the conclusion is only suggested by our result. More research for more comprehensive understanding is still necessary.