Characteristics of Spatial Distribution of Soil Carbon, Nitrogen and Phosphorus Stoichiometry in the Wetland of Poyang Lake, China

Spatial distribution characteristics of soil carbon, nitrogen, and phosphorus, along with the stoichiometric ratios between biogenic elements, is one of the key issues in the research of wetland soils. In this study, the spatial distributions of soil carbon, nitrogen and phosphorus contents and their stoichiometric ratios in the floodplain wetland of Poyang Lake, Jiangxi Province, were characterized by field survey and laboratory analysis. The results show that (1) the variation ranges of soil organic carbon, total nitrogen and total phosphorus in the wetland of Poyang Lake were 4.25-48.13, 0.02-4.25, and 0.08-1.17 g·kg^-1, respectively; the areas with higher soil total nitrogen and total phosphorus densities were located in the eastern part of Poyang Lake, which is related to anthropogenic activities; and the areas with higher soil organic carbon densities were located in the southeastern and southwestern parts of Poyang Lake. (2) The ratio of soil carbon to nitrogen in the wetland of Poyang Lake ranged from 1.07 to 27.15, with an average value of 7.57; the ratio of soil nitrogen to phosphorus ranged from 0.21 to 7.73, with an average value of 1.74; and the ratio of soil carbon to phosphorus ranged from 0.78 to 69.71, with an average value of 13.61. (3) Soil carbon, nitrogen, and phosphorus contents and eco-chemometric ratios are significantly higher in the topsoil than in the subsoil. (4) Stoichiometric ratios are significantly negatively correlated with soil pH and bulk density, and significantly positively correlated with electrical conductivity. These results provide a scientific basis and data support for evaluating and improving the soil quality and function in the floodplain wetland of Poyang Lake.