School of Ecology and Environment,Tibet University,Lhasa
以拉萨河下游甘曲湿地、巴嘎雪湿地、拉鲁湿地和茶巴朗湿地的表层土壤为研究对象,共采集了69个土壤样本。测定土壤pH值、总氮(TN)、总磷(TP)、总钾(TK)、全盐、电导率、氧化还原电位(Eh)、阳离子交换量(CEC)和有机质(OM)作为评价指标。结合单因子肥力评价法和内梅罗综合指数法对拉萨河下游湿地表层土壤肥力进行全面评价,并利用SPSS进行描述统计和相关性分析。以期能掌握拉萨河下游湿地表层土壤的基本环境质量状况,为提升湿地土壤质量提供依据和建议,进一步保证拉萨市湿地生态系统可持续发展。结果表明：(1)利用单因子肥力评价法进行分析,从整体上看,在9个肥力评价指标中,Eh表现为强变异,pH值和TK表现为弱变异,而其余指标均表现为中等强度变异。拉萨河下游湿地表层土壤的pH值呈中性,OM含量和TN含量均处于很丰富的状态,属于第一级别。TP含量和TK含量均处于适中的状态,属于第三级别。全盐含量均值为0.92g.kg-1,电导率均值为2.97ms.m-1,土壤具有较强的保肥能力。氧化还原电位的范围在-55mV~110mV之间,呈还原性。(2)拉萨河下游代表性湿地土壤综合肥力系数(P)大小顺序为茶巴朗湿地(2.01) > 巴嘎雪湿地(1.95) > 拉鲁湿地(1.93) > 甘曲湿地(1.86),4种湿地土壤均属于肥沃等级。影响这4种代表性湿地土壤综合肥力最大的肥力指标是总钾。(3)土壤肥力与Eh呈显著正相关,说明Eh是拉萨河下游代表性湿地土壤肥力指数的限制性因子。以期掌握拉萨河下游湿地土壤的基本环境质量状况,提升湿地土壤质量,为拉萨市的生态文明建设提供依据和建议,保证拉萨市湿地生态系统可持续发展。
A total of 69 soil samples were collected from the surface soils of Ganqu wetland, Ba Gaxue wetland, Lalu wetland and Cha Balang wetland in the lower Lhasa River. Soil pH, total nitrogen (TN), total phosphorus (TP), total potassium (TK), total salt, electrical conductivity, redox potential (Eh), cation exchange capacity (CEC) and organic matter (OM) were measured as evaluation indicators. A combination of the one-factor fertility evaluation method and the Nemero composite index method was used to comprehensively evaluate the fertility of the surface soil of the lower Lhasa River wetland, and descriptive statistics and correlation analysis were carried out using SPSS. In order to be able to grasp the basic environmental quality status of the surface soil of the lower Lhasa River wetland, provide a basis and suggestions for improving the wetland soil quality and further ensure the sustainable development of the wetland ecosystem in Lhasa. The results show that: (1) using the one-factor fertility evaluation method for analysis, on the whole, among the nine fertility evaluation indicators, Eh showed strong variation, pH and TK showed weak variation, while the rest of the indicators showed medium strength variation. The pH of the surface soil of the lower Lhasa River wetland was neutral, and the OM and TN contents were both in a very rich state, belonging to the first level. the TP and TK contents were both in a moderate state, belonging to the third level. The average value of total salt content is 0.92 g.kg-1 and the average value of electrical conductivity is 2.97ms.m-1, the soil has a strong fertility retention capacity. The redox potential ranges from -55mV to 110mV and is reductive. (2) The order of the magnitude of the combined fertility coefficient (P) of the soils in the representative wetlands of the lower Lhasa River is Cha Balang wetland (2.01) > Ba Gaxue wetland (1.95) > Lalu wetland (1.93) > Ganqu wetland (1.86), and all four wetland soils belong to the fertility class. The fertility indicator that most influences the combined fertility of these four representative wetland soils is total potassium. (3) Soil fertility was significantly and positively correlated with Eh, indicating that Eh is the limiting factor of soil fertility index in the representative wetlands of the lower Lhasa River. In order to grasp the basic environmental quality status of wetland soils in the lower Lhasa River, improve wetland soil quality, provide a basis and suggestions for the construction of ecological civilization in Lhasa, and ensure the sustainable development of wetland ecosystems in Lhasa.