System level carbon sequestration by riparian buffer systems as influenced by soil texture, vegetation type and age in southern Ontario

The effect of soil texture, vegetation type and age on system level carbon (C) sequestration in eight riparian buffer systems (RBS) in southern Ontario was investigated. Biomass C sequestration was up to three times (247 Mg C ha-1) greater in deciduous buffers than in coniferous buffers (100 Mg C ha-1) regardless soil texture and age. Mature deciduous tree buffers in clay soils had the highest soil organic carbon (SOC - 177.62 ± 6.193 Mg C ha-1) while the young coniferous buffers in loam soil had the lowest (94.71 ± 6.193 Mg C ha-1). SOC sequestration (154 Mg C ha-1) was significantly higher (p<0.05) in mature buffers compared to adjacent agricultural fields (88 Mg C ha-1), irrespective of soil texture and vegetation type. All RBS had ~66% of SOC in the heavy fraction, indicating stable SOC. Soil NH4+-N was the predominant inorganic N source in all RBS.