中药渣生物有机肥对Hg-Cd复合污染土壤重金属、微生物量碳氮含量及酶活性的影响

Effects of Bio-organic Fertilizer Made from Chinese Traditional Herb Residues on the Content of Heavy Metals,Microbial Biomass Carbon and Nitrogen and Enzyme Activity in Hg and Cd Compound Contaminated Soil

为明确中药渣生物有机肥对重金属污染土壤的改良效果,以中药渣生物有机肥为添加材料、HgCd复合污染土壤为供试土壤,通过土培试验,研究了4种施用比例[0(CK)、0.75%、1.50%和3.00%]对土壤养分含量、有效态重金属(HCl-Hg、DTPA-Cd)含量、微生物量碳氮(MBC、MBN)含量及酶活性的影响。结果表明,土壤pH值,土壤有机质、全氮、有效磷、速效钾、MBC含量,土壤过氧化氢酶、脲酶、蔗糖酶活性均与中药渣生物有机肥施用比例呈直线正相关;土壤HCl-Hg和DTPA-Cd含量与中药渣生物有机肥施用比例均呈直线负相关;而土壤MBN含量则随中药渣生物有机肥施用比例增加呈先增加后降低的趋势。相关性分析结果表明,土壤HCl-Hg、DTPA-Cd含量与土壤养分含量、MBC含量及土壤酶活性均呈显著或极显著负相关;通径分析结果表明,土壤过氧化氢酶活性对HCl-Hg含量的影响最大,土壤脲酶活性对DTPA-Cd含量的影响最大。总体来看,中药渣生物有机肥可有效改善土壤重金属污染状况,提高土壤肥力,可在偏酸性的南方土壤中使用。

In order to understand the improvement effect of bio-organic fertilizer made from Chinese traditional herb residues(BOFCTHR)on heavy metal contaminated soil,an indoor incubation study was conducted to investigate the effects of BOFCTHR[0(CK),0.75%,1.50%and 3.00%]on soil nutrients contents,available heavy metals contents(HCl-Hg,DTPA-Cd),microbial biomass carbon,nitrogen and enzyme activity in Hg and Cd compound contaminated soil.The results showed that soil pH,soil organic matter,total N,available P,available K,and microbial biomass carbon contents,catalase activity,urease activity and invertase activity were linearly and positively correlated with the application ratio of BOFCTHR.The contents of HCl-Hg and DTPA-Cd were linearly and negatively correlated with the application ratio of BOFCTHR.Soil microbial biomass nitrogen tended to increase gradually and then decrease with the increasing application ratio of BOFCTHR.The correlation analysis showed that the contents of HCl-Hg and DTPA-Cd were negatively related to soil nutrients contents,microbial biomass carbon and enzyme activity(except for microbial biomass nitrogen).The path analysis results showed that soil catalase activity had the greatest impact on the HCl-Hg content,and soil urease activity had the greatest impact on the DTPA-Cd content.It is concluded that BOFCTHR can decrease soil heavy metals contents,enhance soil fertility,and it can be used in acidic southern soil.