Estimation of Soil Organic Carbon Concentration accumulated in Mangrove Forest Filtration System

Rate of soil organic carbon (SOC) accumulation and organic matter decomposition in mangrove forest was examined in a mangrove forest filtration system pond within the King's Royally initiated Laem Phak Bia Environmental Research and Development Project that is located in Laem Phak Bia Sub-distric, Ban Laem Distric, Petchaburi Province, Thailand. The study area was divided into two parts: 1) the study site; a mangrove forest filtration system adjacent to a municipal waste water area. 2) the reference site; the natural mangrove forests not affected by municipal waste water. Soil samples were taken at 285 places. The results found that the average of SOC accumulation in the study site at depths of 0-30 cm was 283.36 tons. From the reference site, the average of SOC accumulation was about 66.5 tons. The total area average of SOC accumulation was about 349.87 tons. The compared average values between study site and reference site found the SOC sequestration rate in the study site was higher than reference site at all times. The SOC sequestration had the same pattern in all seasons. The results show that SOC content in the three seasons were not significantly different (p<0.05). The distribution pattern of SOC was assessed by the spatial distribution pattern of SOC concentration interpolated by the Kriging method and indicated that the SOC sequestration rates in the study site were higher than the reference site and the Rhizophora mucronata species growing area contained the highest SOC sequestration.