A Novel Biochar for Soil Remediation:Effects of Its Dosage on Cd Forms and Bacterial Communities in Soil

YANG Guiqiong; LI Huijun; WEI Ting; HUANG Fengcheng; WU Weilong; YANG Changhong; LIN Zhong; ZHEN Zhen

doi:10.19672/j.cnki.1003-6504.1092.23.338

Abstract：In this study different sorts of biochar were prepared using sugarcane bagasse as raw material with three different doses(1%,2%,3%),and then the biochars prepared were to be added to cadmium contaminated soil for the purpose of investi-gating in-situ heavy metal polluted soil remediation effect after the addition of biochars,highlighting the clarification of the changes regarding the soil physico-chemical characteristics,status of cadmium forms distribution,and microbial community structure during the remediation process.Findings of this study included the addition of biochar promoted the transformation of weak acid extractable and reducible of Cd(Ⅱ)into residue fraction of Cd(Ⅱ)in soil mainly by way of increasing pH of soil,organic matter content,and cation exchange capacity,and the dose of 3%,among others,showed a notable boosting effect.When the 60-day experiment came to an end,it was noted that the weak acid extractable fraction Cd(Ⅱ)decreased by 21.14%～29.66%,and reducible fraction Cd(Ⅱ)decreased by 11.15%～22.12%;on the other hand,the content of residue frac-tion Cd(Ⅱ)in the soil added with biochar(ranging from 38.11%to 57.53%)was significantly more than that without biochar(18.55%),but no obvious change was seen in the oxidizable fraction Cd(Ⅱ).In addition,after the application of biochar,there were significant differences in terms of microbial diversity,richness,and evenness in the soil.As for the experiment groups Bio 1,Bio 2,Bio 3 and CK(control group),after the treatment with different doses of biochar,the Ace index and Chao index could be arranged in order of decreasing magnitude:Bio 2>Bio 3>Bio 1>CK;and also remarkably increased was the relative abundance of the main dominant bacteria such as unclassified acidobacteria,Actinomycetaceae,Chloroflexaceae and Gemma-timonaceae:the groups Bio 1,Bio 2 and Bio 3 upgraded the relative abundance of unclassified_p_Acidobacteria by 15.62%,11.34%,22.98%,respectively;and Bio 1,Bio 2 and Bio 3 upgraded the relative abundance of Actinomycetaceae by 56.93%,56.75%,4.53%,respectively,the relative abundance of Chloroflexiaceae 15.32%,5.64%,23.27%,respectively,and that of Gemmatimonaceae 29.57%,14.49%and 61.12%,respectively.In terms of the dosage of biochar,among others,dose of 2%showed the best effect on the microbial community.