不同生物质炭对陇东黄土高原石油污染土壤的修复作用

Remediation effects of the different biochars on crude-oil contaminated soil in eastern Gansu Province of the Loess Plateau

为了分析比较不同生物质炭对陇东黄土高原地区石油污染土壤的修复作用,以玉米秸秆(JYB),小麦秸秆(JXB)和苹果树枝条(JGB)为原料制备生物质炭,以适生植物金盏菊(Calendulaofficinalis)为供试植物(J),在甘肃省庆阳市长庆油田公司采油二厂实施了为期4个月的油污土壤场地修复试验.采用常规方法研究了土壤总石油烃(TPH)降解率、植物生长指标、土壤理化和酶活性及土壤微生物群落结构对外源施用不同生物质炭的响应情况.结果显示:JYB和JGB处理组土壤TPH降解率相对较高(P<0.05),分别为(59.89±2.23)%和(58.17±1.89)%;外源施用3种生物质炭均可显著增加金盏菊株高、地上和地下部干重、土壤速效氮、磷、钾含量以及土壤脱氢酶和多酚氧化酶活性,但与JXB处理组相比,JYB和JGB处理组的根长、过氧化氢酶和脲酶活性则分别增加了23.81%、18.89%,153.12%、80.13%和188.66%、117.45%(P<0.05);此外,JYB和JGB处理组的鞘氨醇单胞菌属、油螺旋菌属、志津氏菌属、Salinimicrobium属、不动杆菌属、红球菌属、食烷菌属和诺卡氏菌属等具备石油污染物降解功能的优势菌属相对丰度显著高于其他处理组(P<0.05).综上,JYB和JGB处理组通过增加金盏菊根际土壤多酚氧化酶(R^2=0.9786,P=0.001)和脱氢酶活性(R^2=0.9713,P=0.005)、微生物群落Shannon指数(R^2=0.7311,P=0.036)、Chao1指数(R2=0.6361,P=0.041)和碱解氮含量(R^2=0.6112,P=0.046)的方式改变土壤微生物群落结构和组成,进而提升了土壤TPH降解率.因此,陇东黄土高原地区油污土壤植物生态修复时宜选用玉米秸秆(JYB)和苹果树枝条(JGB)生物质炭作为土壤调理剂.

In order to analyze and compare the remediation effects of the different biochars on crude-oil contaminated soil in eastern Gansu Province of the Loess Plateau,three types of biochars were fabricated from maize straw(JYB),wheat straw(JXB),and apple tree branch(JYB),together with the indigenous plant,Calendula officinalis,were taken as tested plant(J)to do the in situ ecological restoration for four months in the second oil production plant of the Changqing Oil Field Company.The changes of environmental factors,including soil total petroleum hydrocarbons(TPH)degradation rate,plant growth indices,soil physicochemical traits,enzyme activity,and soil microbial community structure were investigated by the conventional methods.The soil TPH degradation rate in the JYB[(59.89±2.23)%]and JGB[(58.17±1.89)%]treatments was relatively higher than that in the JXB and J treatments(P<0.05).The plant height,plant aboveground and underground dry weight of Calendula officinalis,as well as its rhizospheric soil available N,available P,available K,and activity of soil dehydrogenase and polyphenol oxidase in the JYB,JXB,and JGB treatments were significantly higher than that in other treatments.While compared with JXB treatment,the plant root length,soil catalase and urease activity in JYB and JGB treatments were significantly increase by 23.81%、18.89%,153.12%、80.13%and 188.66%、117.45%,respectively(P<0.05).Furthermore,the dominant genera of soil microbial community with capacity of crude-oil degradation in the JYB and JGB treatments,including Sphingomonas,Oleispira,Simiduia,Salinimicrobium,Acinetobacter,Rhodococcus,Alcanivorax,and Nocardia,were significantly higher than that in the JXB and J treatments(P<0.05).All of the results mentioned above indicated that the soil microbial community structures in the JYB and JGB treatments were different from that of the JXB and J treatments,which could be affected by relatively higher value of soil polyphenol oxidase activity(R2=0.9786,P=0.001),soil dehydrogenase activity(R2=0.9713,P=0.005),soil available N(R2=0.6112,P=0.046),Shannon index(R2=0.7311,P=0.036)and Chao1index(R2=0.6361,P=0.041)of soil microbial community,might be the reason why the soil TPH degradation rate in the JYB and JGB treatments was relatively higher than that of other treatments.Consequently,we proposed that maize straw biochar and apple tree branch would be preferred as the crude-oil contaminated soil remediation conditioner for phytoremediation in eastern Gansu province of loess plateau.