Changes in microbial biomass, CH₄ and CO₂ emissions, and soil carbon content by fly ash co-applied with organic inputs with contrasting substrate quality under changing water regimes

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• 作者：Sang-Sun Lim ; Woo-Jung Choi
• 关键词：Coal fly ash ; Carbonation ; CH4 emission ; CO2 emission ; Substrate quality ; Solid carbon
• 刊名：Soil Biology & Biochemistry
• 出版年：January, 2014
• 年：2014
• 卷：68
• 期：Complete
• 页码：494-502
• 全文大小：983 K

文摘

Application of fine-textured and Ca-rich fly ash may be helpful in enhancing soil carbon content via protecting soil organic C (SOC) by organo-mineral complexation and via reducing CO₂ emission by carbonation (e.g. formation of CaCO₃). However, very limited information is available on the effects of fly ash application on gases loss of C and soil C content. In this study, to estimate the potential use of fly聽ash聽as a soil amendment for SOC enhancement purposes, the effects of fly ash application (0, 5, and 10聽w/w %) on microbial biomass C (MBC), CH₄ and CO₂ emissions, and on soil C content were investigated. A 60-days incubation experiment was conducted with an acidic soil in the presence of organic input (pig manure compost, PMC; hairy vetch, HV) with contrasting substrate quality under changing water regime from water-logged to unsaturated via a transition period. Fly ash application did not affect MBC under water-unsaturated conditions, but reduced (P聽<聽0.01) microbial growth under water-logged conditions, probably due to the increased solubility of a certain toxic element such as arsenic under the anaerobic conditions. Across the 60 days of incubation, the CO₂ emission was reduced by fly ash regardless of organic input by 20.5-41.3%; meanwhile, a decline of CH₄ emission by fly ash application was significant (P聽<聽0.05) only in the HV treatment. Overall, fly ash application slowed down gases C loss and increased soil C content, probably due to the retardation of CH₄ and CO₂ emission as well as the addition of C contained in the fly ash. Biochemical (inhibition of microbial activity), chemical (formation of CaCO₃ via carbonation), and physical (restriction of gas diffusion) mechanisms were suggested for the fly ash effects.