Carbon Sequestration Rates in Organic Layers of Soils under the Grey Poplar (Populus x canescens) Stands Impacted by Heavy Metal Pollution

摘要

To describe carbon sequestration processes in organic layers of forest soils polluted with heavy metal the limit-value method was used to estimate C sequestration rate in poplar litters.A two-year decomposition experiment with litter bags was carried out in 30-year poplar stands planted in the surrounding of a copper smelter.Three study sites (1HML; 2HML and 3HML) were located with increasing distance (0.5,1.5 and 2.1 km) from the smelter and decreasing heavy metal contamination in organic layers.Organic matter content in the litter through fall and litters were also measured using the ignition method.Input of the carbon with litter fall,carbon pools in organic layer and C sequestration rate were estimated.The total litter fall of the study stands varied between 1.2 and 3.5 t C ha-1 year-1 and was the highest at site 3 HML at least polluted with heavy metals.The total carbon pool in studied organic layers varied between 8.3 and 17.7 t C ha-1 year-1 and was the highest at the site 1HML.Carbon sequestration rates estimated with the limit-value approach varied between 344 and 426 kg C ha-1 year-1 and was the highest at the site 3HML.The results suggest that environmental conditions such as pollution of heavy metals from anthropogenic sources may limit C sequestration in forest organic layers.