Temporal and Spatial Patterns of Soil Nutrients in the Wetland of Nanjishan(Poyang Lake), China

To investigate the temporal and spatial distribution characteristics of soil nutrients in the Nanjishan wetland, soils from three typi- cal zones, which covered Carex cinerascens, Triarrhena lutarioriparia and Cynodon dactylon, were collected in five seasons from June 2009 to January 2011 and in three depth(0～15 cm, 15～30 cm and 30～45 cm). The contents of total organic carbon(TOC), total nitrogen(TN)and total phosphorus(TP)were analyzed. Results showed that there were distinct differences in TOC, TN and TP contents among soil depths, sampling seasons and vegetation types of Nanjishan wetland. The TOC and TN contents of surface layer(0～15 cm)soil were remarkably greater than the underlying layer′s(30～45 cm)in all sites. The TOC and TN contents of the soil in the sites of Carex cinerascens, Triarrhera lutarioriparia, not including Cynodon dactylon, had a close relationship with the variable of season. Especially the difference of TOC and TN content of surface soil in the different seasons was remarkable; the soil TP content from all sites remarkably changed with seasons, with aN trend. Additionally, TOC contents of soil had a significantly positive correlation with TN, and a correlation between TOC and TP contents was also detected, but there was no correlation between TN and TP.