铅对土壤微生物生物量和酶活性的影响

在25℃条件下，60d时间内，研究了3种不同土壤不同含铅量对土壤微生物生物量和脱氢酶、碱性磷酸酶、精氨酸氢化作用的影响．结果表明，在土壤含铅量为100μg／g土壤时，微生物生物量和脱氢酶、碱性磷酸酶、精氨酸的氨化作用均无明显变化；当土壤含铅量为400μg／g土壤时，微生物生物量和酶活性均显著减少，在沙反腐殖土中表现明显，在粘质腐殖土和腐殖土中表现较弱．以游离状态存在于土壤中的铅含量在沙质腐殖土中高，在粘质腐殖土中低，大约加入土壤中铅的67％～86％，在土壤中被吸收，土壤中游离态的铅含量与微生物生物量呈负相关．

Effects of Lead on Soil Microbial Biomass and Enzyme Activities

The effect of Pb on soil microbial biomass and enzyme activities in three variablesoils were studied during 60 days incubstion at 25℃. The addition of 100 μg Pb /g soilcaused no rnajor changes in dricrobial biornass and dehydrogenase, alkalina phosphatase andargimne arnmonification activities. The higher concentration of 400 μg Pb /g soil exertedslgnificant inhibitory influence on the above parameters. The reduction in soil persistedthroughout the study Peried. Inhibitory effects of Pb were more severe in sandy loam but lessin clay loam and loam soils. The DTPA extractable Pb was high in sandy loam and low inclay loam soil. About 67%~86% of Pb added was absorbed in soils. The available Pb andmicrobial biomass exhibited a significant negative correlation.