哀牢山常绿阔叶林穿透雨与树干茎流水质特征研究

Water Quality Characteristics of Penetrating Rain and Trunk Stream in Ailaoshan Evergreen Broad-leaved Forest

以哀牢山常绿阔叶林为研究对象,对其生态系统中的穿透雨和树干茎流pH、矿化度、总氮(N)、总磷(P)、电导率(COND)以及Mg 2+、Ca 2+、K+、Na+、HCO 3-、Cl-、SO 42-、PO 43-、NO 3-等理化性质进行测定及分析,开展哀牢山常绿阔叶林降水再分配研究。结果表明:(1)哀牢山常绿阔叶林穿透雨和树干茎流共同存在的离子为:Ca 2+、Mg 2+、K+、Na+、HCO 3-、Cl-、SO 42-、PO 43-、NO 3-,7月份时两者之间离子差异的表现为穿透降雨未检测出Na+,10月份水样中两者离子无差异均未检测出PO 43-;Ca 2+、K+是穿透雨和树干茎流主要阳离子,HCO 3-、SO 42-是穿透雨和树干茎流主要阴离子,HCO 3-、SO 42-是穿透雨和树干茎流含量最多的离子,同时穿透雨和树干茎流水化学元素含量存在明显差异。(2)林冠层对大气降水pH具有降低作用,导致哀牢山常绿阔叶林穿透雨和树干茎流pH降低,水质呈酸性。(3)树干茎流各月矿化度、电导率均高于穿透雨;由于哀牢山林冠附生物固定了大量氮磷元素,使穿透雨和树干茎流的N、P含量较少。

Taking the evergreen broad-leaved forest in Ailao Mountain as the research object,the penetrating rain and trunk stream pH,salinity,total nitrogen(N),total phosphorus(P),electrical conductivity(COND),physical and chemical properties such as Mg 2+,Ca 2+,K+,Na+,HCO 3-,Cl-,SO 42-,PO 43-,and NO 3-were measured and analyzed.The results showed that:(1)Ca 2+,Mg 2+,K+,Na+,HCO 3-,Cl-,SO 42-,PO 43-and NO 3-were common ions in penetrating rain and trunk stream of evergreen broad-leaved forest in Ailao Mountain.Na+was not detected in penetrating rain in July,and PO 43-was not detected in water samples in October.Ca 2+,K+were the main cations in penetrating rain and trunk stream,HCO 3-,SO 42-,HCO 3-and SO 42-were the most abundant ions in penetrating rain and trunk stream,and there were significant differences in chemical element contents between penetrating rain and trunk stream.(2)Canopy layer could reduce the pH value of atmospheric precipitation,which led to the decrease of penetrating rain and trunk stream pH of evergreen broad-leaved forest in Ailao Mountain,and the water quality was acidic.(3)The salinity and electrical conductivity of trunk stream were higher than that of penetrating rain,and the contents of N and P in penetrating rain and trunk stream of Ailao Mountain were less than those of penetrating rain because of a large amount of nitrogen and phosphorus fixed by epiphytes in Ailao Mountain forest.