人造湖对毗邻退化草地土壤含水量、电导率和pH的影响

湖泊作为湿地生态系统的一种重要组成,具有保护和改善生态系统环境的生态效应。以毗邻人工湖的持续放牧的退化草地为研究对象,评估人工湖泊对退化草地土壤理化性质的影响,为改善退化草地提供理论依据。试验结果如下: 1) 毗邻退化草地土壤理化性质对人工湖在距离和深度上产生不同的响应。土壤含水量在距离上随着离湖距离的增加显著降低,0~10 cm土层含水量从距湖10~600 m,降幅分别达到50%(2014年)、48%(2015年)和58%(2016年)。土壤pH则表现相反的趋势。土壤电导率(EC)在距离上先升高,在距湖100 m处达到最大后降低。土壤水分、pH和距离有显著的线性关系,在0~10 cm土层相关系数分别达到70%和50%。2) 在建成湖的3年(2014-2016年)间,表层(0~10 cm)土壤随着建湖年限的增加土壤电导率显著降低,其中距湖10 m处,2016年相对2014年降低了59%。下层土壤(特别是20~40 cm土层)随着建湖年限的增加土壤电导率显著升高,说明土壤盐分自建湖后从表层向下层运移。上层土壤的pH在年际间有显著的降低趋势。综上所述,表明在退化草地上建造人工湖泊后对退化草地的土壤理化性状产生一定的积极作用。

Effects of artificial lakes on moisture,electrical conductivity and pH of adjacent soil on degraded grassland

As an important component of wetland ecosystems, lakes are able to help protect and buffer these ecosystems. In this study, continuously grazed degraded grassland close to an artificial lake in the Bashang area was selected to determine the response of soil physico-chemical properties to the lake in order to identify a potential theoretical basis for the improvement of degraded grassland. The responses of soil physico-chemical properties to the lake differed with distance from the lake and soil depth. Soil moisture decreased significantly with increasing distance from the lake. Soil moisture in the 0-10 cm layer decreased up to 50% (2014), 48% (2015) and 58% (2016), respectively, at 600 m compared to 10 m distance from the lake. Soil pH increased significantly with increased distance from the lake while soil electrical conductivity (EC) initially increased, to a maximum at 100 m, and then decreased. Soil moisture and pH were significantly correlated with distance from the lake, r=0.72 and r=0.44, respectively. Over the duration of the study soil EC decreased in the topsoil (0-10 cm) but increased significantly in lower soil layers, especially 20-40 cm depth indicating that salt had moved down the soil profile since the lake was established. Soil pH in the top soil showed a significant decreasing trend. In summary, the artificial lake had a positive effect on soil physico-chemical properties of degraded grassland.