酸雨胁迫对桉树纯林及混交林土壤pH和酶活性的影响

Effects of Acid Rain Stress on Soil pH and Enzyme Activities of Pure and Mixed Forest of Eucalyptus

以尾巨桉纯林和尾巨桉+大叶栎混交林内的土壤为研究对象,对比分析两者在不同强度的酸雨处理下土壤酶活性的响应机制,以期为酸雨区桉树人工林退化生态系统的恢复和改造提供基础的数据参考。结果表明:与纯林相比,尾巨桉+大叶栎混交林内的土壤有较大的酸缓冲容量,对轻度(p H5.6)和中度(p H4.0)酸雨的胁迫有较好的抵抗能力;土壤蔗糖酶活性随着酸雨p H的降低呈现先升后降的趋势;土壤蛋白酶活性和土壤脲酶活性与酸雨p H呈正相关关系,而且在相同强度的酸雨处理下,尾巨桉+大叶栎混交林的土壤酶活性基本都比纯林的高;土壤过氧化氢酶活性与酸雨p H呈极显著正相关(P<0.01)。

Taking soils of pure Eucalyptus urophylla × E. grandis and mixed forest of Eucalyptus urophylla × E. grandis＋ Quercus griffithii as research objects,the response mechanism of soil enzyme activities under different intensity of acid rain treatment were compared,which provides the basic data reference for the restoration and modification of Eucalyptus plantation ecological system in acid rain area. Result shows that compare with pure forest,soil of Eucalyptus urophylla ×E. grandis ＋ Quercus griffithii have larger acid buffering capacity and have optimal resistance to mild（ p H 5. 6） and moderate acid rain（ p H 4. 0） stress;the enzymatic activity of soil increase first and then decrease with the decrease of acid rain p H. The activity of soil protease and soil urease activity is positively correlated with the p H of acid rain. Under the treatment of same intensity of acid rain,the soil enzymatic activity of soil of Eucalyptus urophylla × E. grandis ＋Quercus griffithii is basically higher than that of pure forest;soil catalase activity is significantly positively correlated with acid rain p H（ P 0. 01）.