桉树人工林对林区水库黑水的影响

以桉树人工林区水库———南宁市天雹水库周边种植的桉树、马尾松两种主要树种为研究对象,分别对比其凋落叶在蒸馏水、水库表层水样、水库底层水样浸泡下的水质特征,并结合2018年春(3月)、夏(7月)、秋(11月)、冬(12月)4个季节对水库近桉树林与马尾松林径流入库区水质情况,分析桉树凋落叶对林区水库黑水的影响。结果表明:桉树浸泡液呈现黄棕色甚至黑褐色,色度显著大于马尾松浸泡液,其单宁酸与溶解性有机碳(DOC)质量浓度分别达到1.14 mg/L和46.40 mg/L,均较马尾松高,水体色度与DOC、单宁酸均呈显著正相关关系,相关系数分别为0.83和0.94;近桉树林区库区的水体的有机质和Mn质量浓度也高于近马尾松林区库区;桉树凋落叶与缺氧的水库底层水体混合后,Fe、Mn质量浓度升高,分别达到1.21 mg/L和2.09 mg/L。

Effects of Eucalyptus plantation on black water in forest reservoirs

Taking two main tree species, Eucalyptus and Pinus, planted around Tianbao reservoir in Eucalyptus plantation area as the study objects, we compared the water quality characteristics of the distilled water, surface water and bottom water of the reservoir in which the litter leaves soaked. Combined with the water quality in runoff area of the reservoir near Eucalyptus and Pinus forest in spring(March), summer(July), autumn(November)and winter(December)in 2018, this paper analyzed the effects of Eucalyptus Plantation on the black water of reservoir in forest area. The results showed that the soaking solution of Eucalyptus is yellow-brown or even black-brown in color, and its chroma was significantly higher than that of the soaking solution of Pinus. The concentration of tannic acid and dissolved organic carbon(DOC)is 1.14mg/L and 46.40mg/L, respectively, which are higher than that of Pinus. The chroma of water body was positively correlated with DOC and tannic acid, and the correlation coefficients were 0.83 and 0.94, respectively. The organic matter and Mn content of waters flowing into reservoir near Eucalyptus forest area were also higher than that near Pinus forest area. The concentration of Fe and Mn increased to 1.21mg/L and 2.09mg/L, respectively, when the leaves of Eucalyptus litter were mixed with the bottom water of anoxic reservoir.