Soil organic carbon enhancement in diverse temperate riparian buffer systems in comparison with adjacent agricultural soils

Soil Organic Carbon (SOC) sequestration within different riparian buffer systems (RBSs) is less documented. This study therefore investigated SOC sequestration potential in the upper 0–60 cm soil layer in diverse RBSs in Southern Ontario, Canada. Mean SOC stocks on an equivalent soil mass basis was significantly higher (p < 0.05) in RBSs (376.164 Mg C ha −1 ) than the adjacent agricultural fields (148.56 9 Mg C ha −1 ), irrespective of the buffer type. There were significant differences (p < 0.05) in SOC sequestration between 41-year-old rehabilitated buffers (179.04 Mg C ha −1 ) and 156-year-old natural forest buffers (489.16 Mg C ha −1 ), and between 99-year-old tree buffers (334.10 Mg C ha −1 ) and 35-year-old grass buffers (121.11 Mg C ha −1 ). Conversely, there was no significant difference (p > 0.05) between 103-year-old coniferous buffers (357.62 Mg C ha −1 ) and 94-year-old deciduous buffers (310.59 Mg C ha −1 ). Annual rate of SOC sequestration was significantly higher (p < 0.05) in rehabilitated buffers (4.71 Mg C ha −1 year −1 ) than in natural forest buffer (3.14 Mg C ha −1 year −1 ) but did not significantly differ (p > 0.05) between deciduous buffers (4.47 Mg C ha −1 year −1 ) and coniferous buffers (3.37 Mg C ha −1 year −1 ) and between tree buffers (3.92 Mg C ha −1 year −1 ) and in grass buffers (3.62 Mg C ha −1 year −1 ).The result of this study implies that the RBS types and management within the buffers can influence C sequestration in soils. Tree buffers have better potential for soil C sequestration than grass buffers. Overall, the results suggest that the establishment of RBSs as best management practice (BMP) should be considered for soil C sequestration in agricultural ecosystems.