骨炭对复合污染土壤生物活性的修复及其时间效应

Bone Char Restoration of Biological Activities in Soil and Plant Under Combined Heavy Metal Pollution

为探究骨炭修复剂对Pb和Cd复合污染土壤中生物活性的修复作用及其随时间变化的效果,在温室条件下通过盆栽实验,研究骨炭修复对土壤酶(脲酶、脱氢酶、酸性磷酸酶)活性与土壤微生物生物量碳含量的影响,测定种植的青菜体内抗氧化酶(过氧化物酶、过氧化氢酶)活性与膜脂过氧化产物丙二醛含量以及青菜生物量的变化。研究结果表明,骨炭修复后,土壤微生物生物量碳含量与对照组相比提高0.33～0.46倍,同一处理下随培养时间的增加,脲酶和脱氢酶活性的变化减小,骨炭的修复效果逐渐减弱;修复后地上部分青菜的生物量是对照组的2.05～4.56倍,青菜体内的过氧化氢酶活性和丙二醛均有明显升高的过程,骨炭对其的修复效果减弱。以上结果显示:骨炭修复能够有效地增强土壤中生物的活性,显著提高作物的产量;在添加时间较短时,骨炭对污染的土壤-植物系统的修复效果更好;而土壤中的脲酶和脱氢酶、植物中的丙二醛能较好指示骨炭的修复作用。

Bone char has shown to reduce the availability of heavy metals in soils, thus improving biological activities. Here a pot experiment was designed to explore the effects of bone char applications on biological activities in soil and plant under Pb and Cd combined pollution. Soil microbial biomass carbon, soil enzymes （urease, dehydrogenase, and acid phosphatase ）, plant enzymes （peroxidase, catalase, malondialdehyde ） of Brassica Campestris and plant dry biomass were measured at different times. The results showed that additions of bone char increased soil microbial biomass by 33%-46% as compared to the control. The enhancing effects of bone char on soil urease and dehydrogenase became smaller as incubation time increased. Dry hiomass of Brassica campestris in bone char treatments was as 2.05 -4.56 times much as that in the control. Plant eatalase activity and malondialdehyde contents increased significantly in later incubation period. These results indicate that bone char could restore biological activities of polluted soil and increase the production of crops, with a better effectiveness in short term. Soil urease and dehydrogenase and plant malondialdehyde could be better indicators of restoration of combined-heavy metal polluted soil by bone char.