酸雨胁迫对木荷和青冈幼苗土壤脲酶活性的影响

目的]为了对外界因素引起的土壤环境变化提供预警。方法]以亚热带常绿阔叶林木荷(Schima superb)、青冈(Cyclobalanopsisglauca)幼苗及无植物对照土壤体系为研究对象,研究酸雨胁迫下土壤脲酶活性的动态变化。结果]在不同酸雨梯度的长期胁迫下,土壤脲酶活性变化有很好的季节性规律,表现为夏季明显高于春季和秋季的特点,且不同季节差异在0.01水平显著。土壤脲酶活性的最大值都出现在2009年8月,最低值出现在2007年春季。在重度酸雨pH 2.5处理下,木荷土壤脲酶活性初期无明显变化规律,后期与CK(pH 5.6)相比无显著差异;青冈土壤脲酶活性变化是促进,无明显变化,试验后期有显著的抑制作用(P0.05);无植物对照开始无明显规律,然后促进,后期显著抑制了土壤脲酶活性(P0.05)。在中度酸雨pH 4.0处理下,试验初期无明显变化规律,后期显著促进了木荷土壤脲酶活性(P0.05),显著抑制青冈土壤脲酶的活性(P0.05),无植物对照土壤脲酶活性仅在酸雨喷淋的第3年夏季有显著抑制作用(P0.05)。结论]了解酸雨胁迫对土壤酶活性的影响需要对各种生态环境、植被、土壤因子长期的测定。

Influence of Acid Rain Stress on Soil Urease Activity of Potted Schima superba and Cyclobalanopsis glauca Seedlings

Objective] The research aimed to provide a feedback of soil ecosystem system changes caused by external factors.Method] Cyclobalanopsis glauca,Schima superb and CK(no plant) were taken as materials.The effects of acid rain on the change of soil urease activity were studied.Result] Under the long-term stress of different acid rain gradient,the urease activity showed a significantly seasonal change.The urease activity in summer was obviously higher than that in the spring and fall,and the characteristics in different season had significant difference(P<0.001).The maximum of soil urease activity were found in August,2009.For Schima superba and Cyclobalanopsis glauca plant-soil unit,the lowest of soil urease appeared in the spring,2007.Acid rain affected the soil urease activity in severe acid rain pH 2.5 processing.Soil urease activity of Schima superba didn′t show obvious change in the beginning,and compared with CK(pH 5.6),didn′t show significant difference later.Soil urease activity of Cyclobalanopsis glauca increased,but had no obvious change and was later inhibited(P<0.05).Soil urease activity of CK appeared no obvious change in the beginning,then was activated,and later was inhibited significangtly(P<0.05).Under the condintion of moderate acid rain(pH 4.0) processing,no obvious changes in the beginning appeared,then urease activity of Schima superba was promoted(P<0.05),soil urease activity of Cyclobalanopsis glauca was inhibited(P<0.05).For no-plant unit,the soil urease activity was inhibited in August,2009(P<0.05).Conclusion] All kinds of ecological environment,vegetation and soil factors should be measured to understand the effects of acid rain stress on soil urease activity.