Effect of Biochar Application on Soil Carbon Fluxes from Sequential Dry and Wet Cultivation Systems

Abstract

Application of biochar has been highly credited for its potential to sequester carbon and GHG mitigation from tropical agro-ecosystems. However, experiments show inconsistent results depending on soil and biochar type, cultivation system, climatic condition and the type of evolved GHGs. This study emphasized on the effect of biochar on carbon emission trends from a sequential dry and wet cultivation system of Bangladesh. An incubation study was conducted with two contrasting soils and eight different treatments viz. control, only fertilizer, three different biochars (10 t·ha-1) with and without recommended fertilizer dose. Results revealed the fact that, emission of carbon was substantially higher from Sara soil than Kalma soil. Biochar treatments did not have any easing effect on CO2 emission at field condition; rather, increased in most of the cases. However, emission was significantly (P < 0.05) suppressed at submerged condition by biochar application. Non-fertilized water hyacinth biochar was most effective in this regard. In general, fertilizer application caused higher emission of CO2. Biochar application was ineffective to control CH4 and CO release to atmosphere and submergence further intensified their emission significantly. The overall results indicate that applied biochars have negligible effect on carbon emission except for reducing CO2 from submerged soils.