南方四种速生树种凋落叶在不同模拟酸雨环境中变化特性研究

The Study of Variation Characteristic of Litters of Four Fast-Growing Species on Simulated Acid Rain with Different Acidities

广西酸雨污染分布广、强度大,对森林生态系统影响较严重。本文选取松树、杉木、桉树、红椎等4种常见的南方速生树种凋落叶,模拟不同强度酸雨环境,研究凋落叶对酸雨的缓冲能力及凋落叶浸泡液营养成分变化差异。通过对叶片营养元素跟踪监测及叶浸泡液酸度、浊度、色度、化学需氧量(COD)、腐殖酸、单宁酸等指标测定发现:不同种类凋落叶元素组成不同,分解过程中浓度变化不同;不同酸度条件下,各凋落叶浸泡液成分变化各异,但桉树叶浸泡液臭度最大;高酸度处理时,红椎叶浊度最高,中、低酸度处理时,红椎叶色度最大;不同酸度处理,桉树叶浸提液COD均高于其他3种;重度酸雨胁迫会减缓水中氧的溶解量,使最大溶解量的发生向后推迟。研究不同种类凋落叶在酸雨胁迫下的动态分解过程,对于预测凋落物对酸雨危害的缓冲能力以及保护森林生态环境具有重要意义。

Acid rain has serious influence the health of forest ecosystem in Guangxi,due to its widespread and high intensity characteristics.The study selected the leaf litter of Pine,China fir,Eucalyptus and Castanopsis hystrix as the reseach object,researched the buffering capacity of leaf litter on simulated acid rain with different acidities,and analyzed the chemical composition of soak solution with leaf litter.The indexes of this experiment were the content of acidity,turbidity,chromaticity,chemical oxygen demand(COD),humic acid,tannic acidwith soak solution and leaf element content.The results showed that different litters have different decomposition property.Odour and COD value of soak solution in Eucalyptus leaves was the highest in all these treatments.But turbidity value of soak solution in Castanopsis hystrix was the highest in high acidity treatments,and chromaticity value was the highest in moderate-low acidity treatments.The content of dissolved oxygen quantity in water was lowered under the treatment of severe acid rain,and was postponed the occurrence of maximum dissolution.It was studied that dynamic decomposition process of different litter leaves under acid rain stress.That was of great significance for predicting the buffer capacity of litter to acid rain and protecting forest ecological environment.