模拟酸雨对土壤生物活性的影响

模拟 pH2、3、4、5、6的雨水,以1、5、10年的积累雨量淋洗3种紫色土。淋洗后的土壤 pH 值对微生物有抑制或刺激作用,其影响较雨水 pH 值更明显。4种土壤酶活性与淋洗后的土壤 pH 值的相关程度亦较与雨水 pH 值为高。雨量积累的影响较 pH 梯度的影响微弱。意味着酸雨对陆生生态系统的危害,首先通过土壤的酸化这一环节。

EFFCTS OF SIMULATED ACID RAIN ON SOIL BIOLOGICAL ACTIVITY

Three types of the purple soil were soacked by simulated acid rainof pH 2.0,3.0,4.0,5.0 or CK of 6.0 and the accumulation of 1 to 10year's acidic percipitation.The results suggested that there was signifi-cant positive correlation between the population of bacteria or actinomy-cetes and soil pH or/and simulated acid rain pH,and it was obviouslyhigher correlation degree in soil pH than acid rain pH,except bacteriaof the calcareous purple soil.Fungi were increased by acid rain.Enzy-matic activities of soils should probably be affected by the change ofsoil pH,as acid rain had no direct significant effects on enzymaticactivities of soil.With the decrease of neutral and acidic purple soilpH by acid rain,there was significant positive correlation between dehy-drogenase,urease or catalse and soil pH.Significant negative correlationwas invertase.Long-time effects of acid rain was similar to acid degreeeffects of acid rain and soil on soil biological activities.The resultindicates:the first acid rain may change pH of soil and then the microf-lora and enzymatic activities of soil are affected by the acidificationof soil.Therefore,it is very important to study the potential effects ofacid rain on terrestrial systems.