Effect of Land Use Management Patterns on Mineralization Kinetics of Soil Organic Carbon in Mount Bambouto Caldera Area of Cameroon

• 作者: Formeluh Abraham Toh Lawrence Monah Ndam Ngosong Christopher Tsi Evaristus Angwafo
• 来源期刊: 土壤科学期刊(英文)
• 学科: 农学
• 关键词: Land Use Carbon Mineralization Kinetic Models Mount Bambouto Caldera
• 年，卷（期）: 2020,（9）
• 页码范围: 391-409
• 页数: 19页
• 分类号: S15

摘要

<p align="justify"> <span style="font-family:Verdana;"></span><span style="font-family:Verdana;"></span>Soil organic carbon (SOC) mineralization was carried out on soil samples collected from two depths: 0 - 20 cm and 20 - 40 cm for all land use (LU) types (grasslands, croplands, natural forest/fallow lands, cocoa/palm plantations, and settlement/agro-forests). Microbiological analyses were carried out by measuring microbial activity in 40 g of dried soil samples wetted to 60% water holding capacity and incubated at 27 °C. Carbon dioxide (CO₂) emission was measured for 10 weeks using a CO₂ trap. Descriptive and graphical analyses of CO₂ respiration were done using CO₂emission data. Models were developed to describe CO₂ respiration and the first order kinetic model provided best fit to C-mineralization. Potentially mineralizable carbon (C_o) and C-mineralization rate were higher in grasslands than other LU types, indicating a higher rate of microbial activity and carbon cycling. Metabolic quotient was higher in forest/fallow lands and reflects greater stress of the microbial community and a high requirement of maintenance energy. Grasslands enhanced more SOC accumulation and decomposition, suggesting a better carbon sink than other land use and management systems (LUMS). Microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) varied across LU patterns with maximum values in grasslands and minimum values in natural forest/fallow lands insinuating better soil quality for grasslands. MBC and SOC positively correlated with C_o and C-mineralization, which intimates that C-mineralization is influenced by availability of MBC and SOC. Metabolic quotient (qCO₂) negatively correlated with microbial quotient (MBC:SOC), depicting that higher values of qCO₂ signify difficulties in using organic substrates during microbial activity as a result of low MBC:SOC. Changes in LUMS affected the mineralization kinetics of SOC