四种南方常见速生树种凋落叶浸泡实验研究

Comparative study on soak characteristic of litters in four different southern fast-growing tree species

为了研究南方速生树种凋落叶浸泡特性,以松、杉、桉、红锥为研究对象,对比各凋落叶在浸泡过程中的水质变化特征。结果显示:桉树凋落叶浸泡液pH值比其他低、臭味强且持久,色度开始较大,但随着浸泡时间的增加逐渐降低,最终低于红锥叶。四种凋落叶总氮、总磷、总钾均呈现释放、积累、释放的波动过程,差异不大。腐殖酸在一定程度上影响着pH值的大小,而水质颜色的深浅与臭味的强弱并没有直接相关性。根据实验所得数据,其中桉树凋落叶在水中浸泡最先引起水质发黑,这可能与桉树人工林区偶有发生的黑水现象有关,红锥次之;松树与红锥凋落叶最先引起水质发臭,但是强度逐渐降低,只有桉树凋落叶在127天内一直保持强的臭味。

In order to investigate the soak characteristic of litters in southern fast-growing tree species, this experiment used pine, China fir, eucalyptus and Castanopsis hystrix to study the water quality alteration of them. The results showed that pH value of soak solution of eucalyptus was lower than others, and odour was stronger and more durable. Meanwhile the chromaticity color was very high in the beginning of the immersion, but decreased with the increase of soaking time, in the end lower than soak solution of Castanopsis hystrix leaves. The values of TN, TP and TK were all followed the same rules as release-accumulation-release, with no significant difference. In addition, humic acid content affected the value of pH to a certain extent, but did not directly related to chromaticity color or odour. The immersion fluid soon turned black due to soak eucalyptus leaves in the water. This may explain why eucalyptus artificial forests occur black water pollution by accident. On the other hand, soak solutions of pine and Castanopsis hystrix smell firstly, but the intensity gradually decreases. Only the odour of soak solution of eucalyptus has remained constant during the experiment.