摘要
1998年 4月至 1999年 3月对广州市白云山马尾松林和常绿阔叶林、广州市龙眼洞马尾松林两试验点进行了酸雨的监测 ,并测定和分析了林内穿透雨物理量及化学量 ,旨在探讨酸雨对不同森林冠层养分淋溶规律的影响。结果表明 :( 1)广州市酸雨占降雨次数的 79.7%或占降雨量的95.1%。 ( 2 )酸雨通过林冠层后 ,pH值明显增加。 ( 3)在马尾松林和常绿阔叶林中 ,某些单次降雨出现SO4 2 - 、NO3- 、NH+4 、Al3+、Na+的负淋溶现象 ,说明森林对这些离子 (特别是NO3- 、Al3+)具有吸收作用 ;阔叶林全年的NO3- 和Al3+净淋溶为负值 ,说明阔叶林比马尾松林对这两种离子具有更强的吸收能力。 ( 4 )雨水酸度增加 (即 pH值减小 ) ,明显地提高阳离子Ca2 +、Mg2 +、K+和Na+冠层淋溶百分率。 ( 5)NH4 +、SO4 2 - 和NO3- 这 3种离子的冠层淋溶百分率明显地与雨水中SO2 - 4及NO3- 浓度成负相关。 ( 6)SO4 2 - 、NO3- 、NH4 +、Al3+、Ca2 +、Mg2 +、K+、Na+的冠层淋溶序列 ,在白云山常绿阔叶林中为K+>Mg2 +>SO4 2 - >NH4 +>Ca2 +>Na+>Al3+>NO3- ;在白云山马尾松林中为K+>Mg2 +>NH4 +>SO4 2 - >Ca2 +>NO3- >Na+>Al3+,在龙眼洞马尾松林中为K+>Mg2 +>SO4 2 - >NH4 +>Ca2 +>Na+>NO3- >Al3+。
The rainfall and throughfall in Pinus massoniana forest and subtropical evergreen broad leaved forest at Baiyunshan and in P. massoniana plantation at Longyandong were measured during the period of April 1998 to March 1999. The collected samples of rainfall and throughfall were used for analyzing pH value and major element compositions (SO 4 2- ,NO 3 -,NH 4 +,Al 3+ ,Ca 2+ ,Mg 2+ ,K +,Na +). And hence, the crown leaching of main chemical ions in the forests and the relationships between canopy leaching and acid rain were studied. The results indicates that:(1)The frequency of acid rain in Guangzhou is 79.7%, and the amount of acid rain accounts for 95.1% of annual rainfall. (2)The pH value of throughfall in the forest ecosystems is obriously higher than that of rainfall because of the ion exchange in canopy. (3)During the process of some rain, SO 4 2- ,NO 3 -,NH 4 +,Al 3+ ,Na + appeared negative leaching in the pine forests and evergreen broad leaved forest, this phenomenon illustrates that the forests can absorb these ions (especially NO 3 - and Al 3+ ) under the condition of acid rain. In view of annual net crown leaching, the net leaching of NO 3 - and Al 3+ in the broad leaved forest is -0.85 and -0.06 kg·hm 2·a -1 , respectively, and that in two pine forests are positive leaching, this also illustrates that the evergreen broad leaved forest has great capacity of absorbing NO 3 - and Al 3+ . (4)Increase of acidity of rain can obviously increase the ratio of crown leaching of Ca 2+ ,Mg 2+ ,K + and Na +. (5)The ratios of crown leaching of NH 4 +, SO 4 2- and NO 3 - have close negative interrelation to the concentration of SO 4 2- and NO - 3 in rainfall. (6) The crown leaching array of major elements from high to low in evergreen broad leaved forest at Baiyunshan is K +>Mg 2+ >SO 4 2- >NH 4 +>Ca 2+ >Na +>Al 3+ >NO 3 -, in P. massoniana forest at Baiyunshan is K +>Mg 2+ >NH 4 +>SO 4 2- >Ca 2+ >NO 3 ->Na +>Al 3+ , in P. massoniana plantation at Longyandong is K +>Mg 2+ >SO 4 2- >NH 4 +>Ca 2+ >Na +>NO 3 ->Al 3+ .
出处
《林业科学研究》
CSCD
北大核心
2000年第6期598-607,共10页
Forest Research
基金
广东省自然科学基金项目"大气污染对珠江三角洲森林的影响及经济损失评估"(960515)
广东省林业厅项目"水源林水质生态效益及森林优化模式研究"的部分研究内容。
关键词
酸雨
冠层淋溶
马尾松
南亚热带常绿阔叶林
acid rain
crown leaching
Pinus massoniana
southern subtropical evergreen broad leaved forest
