[Distribution characteristics of soil organic carbon and its composition in Suaeda salsa wetland in the Yellow River delta].

Applying the method of physical fractionation, distribution characteristics of soil organic carbon and its composition in Suaeda salsa wetland in the Yellow River delta were studied. The results showed that the heavy fraction organic carbon was the dominant component of soil organic carbon in the studied region. There was a significantly positive relationship between the content of heavy fraction organic carbon, particulate organic carbon and total soil organic carbon. The ranges of soil light fraction organic carbon ratio and content were 0.008% - 0.15% and 0.10-0.40 g x kg(-1), respectively, and the range of particulate organic carbon ratio was 8.83% - 30.58%, indicating that the non-protection component of soil organic carbon was low and the carbon pool was relatively stable in Suaeda salsa wetland of the Yellow River delta.

[Spatial distribution characteristics of organic carbon in the soil-plant systems in the Yellow River estuary tidal flat wetland].

Well-understand the organic carbon status in the Yellow River delta is the most important for studying the biogeochemical processes of the muddy-sandy coastal wetland and ecological restoration. The spatial distribution characteristics and its impact factors of organic carbon in the plant-soil systems of new-born tidal flat wetland in the Yellow River estuary were studied. The results showed that the difference of plant organic carbon content in different plant communities were not obvious, however significant difference of the plant organic carbon density was observed. Moreover, the M-shaped spatial distribution of the plant organic carbon density, which was similar to the plant biomass, was found in the study. The organic carbon contents in top soils were varied from 0.75 to 8.35 g x kg(-1), which was much lower than that in the typical freshwater marsh wetlands ecosystem. The spatial distribution trend of soil organic carbon density was similar to the soil organic carbon. The correlation analysis showed that soil organic carbon density was negatively correlated with pH, and positively correlated with TN, C/N and salinity. However, the correlations of plant organic carbon density with the soil organic carbon density, TN, C/N, pH and salinity were not significant.