Distribution Characteristics And Influential Factors Of Soil Organic Carbon In Mangrove Wetlands In Guangdong Province

Mangrove ecosystem is a high productive natural ecosystem and has significant potential for carbon sequestration. It plays an important role in in the global carbon cycle and carbon balance. As long-term logging and anoxic environment, mangrove soil stores lots of organic carbon and becomes a huge carbon pool. Mangrove soil plays a role as sources and sinks in the global carbon cycle. Soil carbon storage and spatial distribution have become a hot issue of global organic carbon cycle research.To study the distribution regular of mangrove soil organic carbon and soil organic carbon influencing factors,this paper studied the mangrove in Guangdong province, including eastern Guangdong, Pearl River Estuary, western Guangdong and Leizhou Peninsula. Vegetationcommunity composition and habitat was investigated and soil samples were collected. Then soil organic carbon and soil basic physical and chemical properties were measured. All data were processed by Excel and SPSS. Moreover, the distribution of soil organic carbon was explored in different areas and the influencing factors of soil organic carbon content were analyzed. The results showed that:1、Soil organic carbon content in 30 centimeter depth was in the range of 4.3~68.7g/kg, the average was 16.48g/kg, and the variation was 0.71. The regular pattern of region distribution was: Eastern Guangdong was the area which mangrove soil fixed highest soil organic carbon content. Pearl River Estuary and Western Guangdong were next. The lowest was Leizhou Peninsula. The average value were 26.42g/kg、24.89g/kg、16.32g/kg、10.93g/kg.2、The vertical distribution feature was that the value of soil organic carbon content in 10~20cm soil layer was higher than 0~10cm soil layer and 20~30cm soil layer. The average value from top to bottom were 19.55 g/kg、19.57 g/kg and 17.62 g/kg respectively. There was no significant difference in different soil layer.3、The soil organic carbon density was 0.97 to 13.18 kg/m2, the average was 4.22 kg/m2, and the variation was 0.50. At a rough estimate, the soil organic carbon reserves was 1.27×104~4.46×104t(30cm).4、Correlation analysis showed that, there was a significant positive correlation(p<0.05) between soil organic carbon content and soil moisture. Soil organic carbon content and soil bulk density showed an extremely significant negative correlation(p<0.01), so as p H. The correlation between soil organic carbon content and soil porosity was significant positive in eastern Guangdong, Pearl river estuary and western Guangdong, but was not obvious in Leizhou Peninsula.5、Soil organic carbon content of different mangrove communities in Pearl river estuary was various, and the order was Kandelia candel >Avicennia marina> Acanthus ilicifolius >Aegiceras corniculatum >Sonneratia apetala. The result showed that, the correlation between soil organic carbon content and tree height was not obvious, so as vegetation coverage. The influence of mangrove communities to soil organic carbon content is the result from combined effect of all vegetation index such as vegetation types, tree height, vegetation coverage, diameter at breast and structural features.6、Interference of human factors on mangrove is extremely intense.Human factors are mainly as follows, mangrove harvesting and grazing, construction and development in coastal area, wastewater of aquaculture pond, living garbage and sewage, and so on. In addtion, the spread of Spartina alterniflora growth rapidly, and Sonneratia apetala has diffusion phenomenon.