Effects of rice husk biochar charred at different time on soil chemical properties, rice growth and yield

Sustainable rice production in Sub-Saharan Africa especially in Nigeria faces serious constraints due to soil infertility. Recycling of rice residues through biochar production and applying it to the soil could be a possible approach to address the soil fertility constraints facing rice production. A pot experiment was conducted at Imo State University to investigate the effect of rice husk biochar on some selected soil chemical properties, growth and yield of rice. Four treatments evaluated in the pot experiment include rice husk biochar charred at 250oC for 60, 90 and 120 minutes together with control (no amendment). The treatments were replicated three times and laid out in completely randomized design (CRD). The soils in the pots were both treated with basal dose NPK (15:15:15) at 200kgha-1 while biochar was applied at the rate of 10tha-1 to the amendment soils. Application of biochar in this experiment appreciably increased the soil pH, available phosphorus, OC, TN, exchangeable cations, CEC and available silicon in biochar treated pots compare to control pots. The degree of soil improvement was proportional to the charring time. The rice husk charred for 120 minutes (RHB120) showed the highest effect on most of the soil chemical properties evaluated. Biochar amendment was found not to have much influence on the rice agronomical parameters except grain weight in which the highest value was found in soil treated with RHB120 (12.5gpot-1). Therefore, converting rice husk to biochar and applying it to the soil can improve soil fertility status and yield of rice in Nigeria. Keywords: Rice Husk Biochar, Soil Chemical Properties, Rice Growth, Rice Yield