Dynamics of C and N in a clay loam soil amended with biochar and corn straw

An incubation study was conducted to determine the influence of biochar and corn straw on CO2-C emission, soil organic C, microbial biomass C and N, total N, and mineral N (NH4+-N and NO3--N) in a clay loam soil. Six treatments viz., CK (Control); S (Soil + 1% straw); B1 (Soil + 0.5% biochar); B2 (Soil + 2% biochar); SB1 (Soil + 1% straw + 0.5% biochar); SB2 (Soil + 1% straw + 2% biochar) were tested with three replications. Results showed that straw addition to soil with or without biochar increased CO2-C emission while sole-biochar addition (2%) reduced it. Straw and biochar also increased the soil microbial biomass C and N but greatest increase in microbial biomass N (111.9 µg g-1) was recorded by biochar-straw combination. SOC and total N significantly increased following biochar and straw additions which suggest that organic amendments can improve soil chemical properties. Additionally, for soil mineral N, biochar reduced NH4+-N and NO3--N concentrations while straw increased NH4+-N concentration but greatly reduced that of NO3--N.