Abstract:

In order to study the relationship between groundwater level and soil physical and chemical properties, on the basis of natural and topographical reasons to form the water table gradient, the soil physical and chemical properties of high water table (SI), middle water table (SⅡ) and low water table (SⅢ) in Gahai swamp meadow wetland were studied. The results showed that:with the decrease of groundwater level, the proportion of fine sand (<0.2 mm) in soil particle composition decreased, the content of coarse sand (2~0.2 mm) increased, the soil bulk density increased significantly, and the soil bulk density increased with the increase of soil depth. The average soil total porosity and maximum water holding capacity of SI plots were 1.19 and 1.36 times, 1.93 and 2.75 times of SⅡ and SⅢ plots, respectively. The contents of organic carbon, total nitrogen and total phosphorus in SI soil of Gahai Wetland were 86.87% and 167.35%, 99.88% and 115.95%, 22.32% and 58.97% higher than those of SⅡ and SⅢ, respectively. The reduction of groundwater level significantly affects the decomposition and conversion of organic matter, accelerates the rate of oxidative decomposition, and results in a decrease in the content of soil nutrients (carbon, nitrogen, phosphorus), which makes the soil environment in wetland worse.

Key words: Swamp meadow wetland, Groundwater table, Physical and chemical properties of soil, Soil water storage capacity

摘要：

为了研究地下水位与土壤理化性质之间的关系，依据自然原因和地形原因形成的水位梯度，对尕海沼泽化草甸湿地区内高水位（SI）、中间水位（SⅡ）和低水位（SⅢ）的土壤理化性质进行了研究。结果表明：尕海沼泽化草甸湿地随着地下水位的降低，土壤颗粒组成中细砂（<0.2 mm）比例下降，粗砂（2~0.2 mm）含量增加，土壤容重显著升高，且土壤容重随土层深度的增加而增大。SI样地平均土壤总孔隙度、最大持水量分别是SⅡ样地的1.19和1.36倍、SⅢ样地的1.93和2.75倍。尕海湿地SI土壤有机碳、全氮、全磷含量比SⅡ和SⅢ分别高出了86.87%和167.35%、99.88%和115.95%、22.32%和58.97%，地下水位的降低显著影响了有机质的分解转化，加快了氧化分解的速率，造成土壤养分（碳、氮、磷）含量的减少，使得湿地土壤环境恶化。

关键词: 沼泽化草甸湿地, 地下水位, 土壤理化性质, 土壤蓄水性能