不同原材料生物炭对农田土壤阿特拉津去除性能及微生物群落结构的影响

【目的】研究不同原材料生物炭对农田土壤阿特拉津去除效果和微生物群落的影响,获得去除土壤阿特拉津的最佳生物炭类型,为阿特拉津污染农田土壤的强化修复提供参考。【方法】以牛粪、甘蔗渣和污泥为原材料制备生物炭,分别于0、10、20、30和40 d测定阿特拉津降解率及土壤pH、有机质含量、腐殖质含量、酶活性和细菌群落结构,并采用冗余分析探明阿特拉津降解率与环境因子及土壤细菌群落结构的相关性。【结果】添加生物炭可明显促进土壤中的阿特拉津降解,3种生物炭的降解率排序为甘蔗渣生物炭(67.94%)>牛粪生物炭(58.39%)>污泥生物炭(48.63%)。同时,添加生物炭显著提高土壤p H、有机质和腐殖质含量(P<0.05,下同),提升微生物活性和群落结构多样性,加速阿特拉津的生物降解,以甘蔗渣生物炭效果最显著,相较于不添加生物炭(CK),pH提升23.76%,有机质含量升高4.39 g/kg,腐殖质含量升高2.24 g/kg。此外,施入生物炭显著提高土壤脱氢酶、过氧化氢酶和脲酶活性,并促进阿特拉津降解菌鞘脂单胞菌科(Sphingomonadaceae)、伯克氏菌科(Burkholderiaceae)、链霉菌科(Streptomycetaceae)、微球菌科(Micrococcaceae)和小单孢菌科(Micromonosporaceae)的相对丰度提升。冗余分析表明,环境因子及降解功能微生物均对阿特拉津的降解做出贡献,甘蔗渣生物炭处理与pH、有机质、阿特拉津降解率及腐殖质呈正相关。【结论】施入生物炭可改善土壤理化性质(pH、有机质和腐殖质),明显提升阿特拉津降解菌鞘脂单胞菌科、伯克氏菌科、链霉菌科、微球菌科和小单孢菌科相对丰度,进而加速土壤中阿特拉津的去除,以甘蔗渣生物炭的效果最佳。收集废弃甘蔗渣制成生物炭,既可实现农业废弃物的回收利用,又能助力农田土壤中阿特拉津污染修复和地力提升。

Effects of biochar from different raw materials on atrazine removal and microbial community structure in farmland soil

【Objective】In order to obtain the best biochar type for atrazine removal,the effects of different biochars on atrazine removal and microbial community in farmland soil were studied,which could provide a reference for farmland soil remediation with atrazine.【Method】Biochar was prepared with cow dung,bagasse and sludge as raw materials. Atrazine degradation rate,soil p H,organic matter content,humus content,soil enzyme activities and microbial community structure were determined at 0,10,20,30 and 40 days,respectively.Redundancy analysis was used to explore the correlation between atrazine degradation rate,environmental factors and bacterial community structure. 【Result】The results showed that the addition of biochar could greatly promote atrazine degradation in soil,which performed as the atrazine degradation rate of bagasse biochar(67.94%)>cow dung biochar(58.39%)>sludge biochar(48.63%). Meanwhile,biochars application significantly increased the p H value,organic matter and humus content of soil(P<0.05,the same below),improved microbial activity and diversity of community structure,and accelerated the biodegradation of atrazine,in which the bagasse biochar had the most significant effect that increased the pH value,organic matter and humus of soil by23.76%,4.39 g/kg and 2.24 g/kg respectively than without biochar(CK). In addition,biochar application significantly increased the activities of soil dehydrogenase,catalase and urease,and promoted the abundance of atrazine-degrading microorganisms Sphingomonadaceae,Burkholderiaceae,Streptomycetaceae,Micrococcaceae and Micromonosporaceae.Redundancy analysis showed that both environmental factors and functional microorganisms contributed to the degradation of atrazine,and bagasse biochar was positively correlated with the pH,organic matter,atrazine degradation and humus.【Conclusion】Application of biochar improves soil physicochemical properties(pH,organic matter and humus),significantly increases the abundance of atrazine degrading bacteria Sphingomonadaceae,Burkholderiaceae,Streptomycetaceae,Micrococcaceae and Micromonosporaceae,and thus accelerates the removal of atrazine from soil,among which bagasse biochar has the best effect. Biochar made from waste bagasse can be used to recycle agricultural waste,repair atrazine pollution and improve soil fertility in farmland.