Abstract:

Water level in wetland may affect soil properties of the wetland.Effects of water level on soil properties of reed wetlands in Hangzhou Bay Polder were studied. The vertical distribution patterns of the soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP) along the soil profile and their stoichiometric ratios relative to water level were investigated. Results show that: (1) on the whole, SOC and TN contents decreased at first then increased with rising water level, while the content of TP did not change much(P<0.05); (2) when the soil remained unsubmerged (Water level 0) C/P, N/P and C/N declined with soil depth, but when the soil was submerged, regardless of water levels, their initial decreases were followed by increases; (3) SOC was positively correlated with soil N/P and TN with soil C/P, while TP was negatively, but not so significantly with soil C/N at all water levels; and (4) soil pH was the major factor affecting SOC, TN and TP at 0cm water level, but the effect faded with rising water level. SOC and TN accumulations in the deep soil layers increased with rising water level, while TP did not change much(P<0.05).

Key words: Hangzhou Bay wetland, water level gradient, organic carbon, total nitrogen, total phosphorus, pH