Soil microbial biomass carbon and carbon dioxide response by glucose-C addition in black soil of China.

The soil microbial biomass, atmospheric carbon dioxide and abundance of decomposer are influenced by rate and addition pattern of glucose carbon. The present study was conducted to evaluate the effect of single and repeated additions of glucose-C on soil microbial biomass carbon (SMBC) and CO₂ response in black soil of China. The incubator study comprising of 116-days was conducted in different fertility levels of black soil of Jilin province of China, to determine the effects of glucose addition patterns viz single addition (2% glucose-C once application) and repeated addition (2% glucose-C in five splits) on soil microbial biomass carbon and CO₂ accumulation. Fortygram air dried soil was filled into 250 ml Schott bottle and bottles were arranged in CRD-factorial design with 5 repeats. Factor (A), included glucose addition patterns (single & repeated additions). Factor (B), consisted of soil fertility levels: low, medium and high on the basis of soil organic carbon. Thereafter glucose-C (2%) solution was added drop wise to soil. The addition patterns showed positive response on SMBC, CO₂ evolved and CO₂ accumulation. Over all mean (low, medium and high fertility soils) of repeated addition depicted 32% and 0.92% higher values of SMBC than control and single additions, respectively. The CO₂ emission of repeated addition was 21.3% higher in low fertility soil. The mean CO₂ accumulation showed higher values in low fertility soil by single addition than repeated and control in all soils. Single glucose-C addition in combination with different soil fertility levels augmented the microbial biomass and triggered carbon mineralization for shorter period (up to 3 weeks). The repeated addition of glucose in combination with different soil fertility levels also enhanced soil microbial biomass carbon and CO₂ in longer incubation period. It is concluded from this study that microbial starvation for organic carbon was very high hence; repeated addition may be suggested to meet C demand of microbes. [ABSTRACT FROM AUTHOR]