稻壳与稻壳生物炭对镉污染土壤微生物群落结构影响研究

Effects impact of rice husk and rice husk biochar on the microbial communitystructure in cadmium-contaminated soil

为探究稻壳与稻壳生物炭对镉(Cd)污染土壤微生物群落结构的影响,本研究设置未污染土壤(CK)、受Cd污染土壤(CD)、添加2%(Wl W)稻壳生物炭(BO)和添加稻壳(DK)4个处理组,探讨施用等碳量稻壳和稻壳生物炭对土壤理化性质、酶活性、微生物群落结构等方面的影响.研究结果表明,相较于CD组土壤,BO组和DK组的总有机碳(TOC)含量分别提高了10.05%和5.02%,BO、DK组的总氮(TN)含量分别提高了2.96%和8.94%;总磷(TP)含量变化不显著;DK组的碱解氮(AN)含量、蔗糖酶活性、脲酶活性较CD组分别提升了5.07%、307.20%、16.83%,而BO组提升并不显著;各处理组优势菌种均为变形菌门(Proteobacteria)、放线菌门(Actinobacteriota)、厚壁菌门(Firmicutes)和绿弯菌门(Chloroflexi);DK组较CK组群落结构变化趋势与CD组完全相反;蔗糖酶活性与厚壁菌门呈显著正相关(p<0.001),与酸杆菌门、绿弯菌门呈显著正相关(p<0.01);鞘脂单胞菌属(Sphingomonas)的丰度:CD>BO>CK>DK,且鞘脂单胞菌属与脲酶活性、蔗糖酶活性和DOC含量呈显著负相关(p<0.001);DTPA-Cd(二乙烯三胺五乙酸提取的镉)浓度与芽孢杆菌属(Gemmatimonas)呈显著负相关(p<0.01),DK组芽孢杆菌属含量最高(11.75%)且DTPA-Cd含量最低(0.907 mg·kg-1).综上,等碳量添加稻壳和稻壳生物炭,稻壳生物炭在提升土壤TOC含量方面优于稻壳,而提升TN、TP、酶活性、碱解氮含量以及处理土壤中DTPA-Cd等方面稻壳效果更优.

In order to investigate the impact of rice husk and rice husk biochar on the microbial community structure of cadmium(Cd)-contaminated soil,four treatment groups were set up in this study:uncontaminated soil(CK),Cd-contaminated soil(CD),biochar with 2%(W/W)rice husk(BO),and rice husk only(DK).Their impact on the soil's physicochemical properties,enzyme activities,and the structure of the microbial communities were investigated.The results showed that the total organic carbon(TOC)of the BO and DK groups increased by 10.05%and 5.02%respectively,and the total nitrogen(TN)of the BO and DK groups increased by 2.96%and 8.94%,respectively,compared to CD group.the changes of the total phosphorus(TP)content were insignificant;and the alkaline nitrogen(AN)content,sucrase activity,and urease activity of the DK group increased by 5.07%,307.7%,and 16.83%respectively,compared to CD group.While the BO group was not significantly improved;the dominant bacterial species in each treatment group were Proteobacteria,Actinobacteriota,Firmicutes and Chloroflexi.community structur change in the DK group was opposite to that in the CD group.The DK group had a more favorable environment compared to the CD group.The trend of structural changes in the DK group was completely opposite to that of the CD group.sucrase activity positively correlated with specific phyla(thick-walled,Acidobacterium and Chloroflexi)(p<0.01).The abundance of Sphingomonas was CD>BO>CK>DK,and Sphingomonas showed a high significant negative correlation(p<0.001)with the activities of urease,sucrase,and the contents of DOC.The concentration of DTPA-Cd(cadmium extracted by diethylenetriamine pentaacetic acid)negatively correlated with Gemmatimonas abundance(p<0.01),with DK group exhibiting the highest Gemmatimonas content(11.75%)and the lowest DTPA-Cd levels(0.907 mg·kg-1).rice husk biochar outperformed rice husk in enhancing soil TOC when applied at the same amount,while rice husk was more effective in enhancing TN,TP,enzyme activity,alkaline dissolved nitrogen content and DTPA-Cd in treated soil.