生物质炭对镉污染土壤微生物多样性的影响

Effects of biochar(BC) on microbial diversity of cadmium(Cd) contaminated soil

通过向模拟镉污染土壤中添加生物质炭,研究其对土壤中微生物活性及功能的影响,以期揭示生物质炭钝化镉污染土壤的作用机制.采用Biolog-Eco微平板法,围绕各粒级土壤团聚体中微生物在碳代谢功能方面对不同量生物质炭的响应机制开展室内试验.实验结果表明:Cd污染条件下,生物质炭的施用提高了土壤中微生物群落碳源代谢活性及功能多样性,2.5%生物质炭处理下的提高效果尤为突出;土壤微生物的碳源代谢活性及功能多样性在不同粒级团聚体中呈"V"型分布,5-1mm、<0.25mm团聚体中最高.<0.25mm微团聚体中微生物碳代谢功能多样性重金属Cd胁迫效应与生物质炭保护效应均最显著;土壤微生物McIntosh指数上升了32.68%-135.52%,群落物种均一度发生巨大的变化;Cd污染土壤中微生物对其他类碳源化合物有偏嗜性,进一步分析显示,生物质炭处理组与单施Cd对照组微生物碳源利用上起分异作用的是羧酸类和糖类2类碳源化合物.

In recent years,soil Cd Contamination has become more and more prominent,so BCs were widely applied toagricultural soils as a soil conditioner.The effects and mechanism of biochar on remediation of Cd contaminated soils,especially on the soil microbial activity and function were revealed in this paper.A pot experiment was conducted tomainly focuses on investigating how different BCs ratios application to different particle size soil aggregates influencesmicrobial community structure and functional diversity,with the method of Biolog-Eco micro plate.Analysis results allshowed that:the application of BCs had a positive effect on Cd contaminated soil microbial community,which improvedmicrobial carbon metabolic activity and functional diversity,in particular the2.5%BCs treatment was the most significant.The soil microbial functional diversity showed'V'type distribution rule in soil aggregates,which the5~1mm and<0.25mm aggregates were highest.With the increased of Cd pollution and the protection of BC in<0.25mm aggregates.The McIntosh index of soil microbial communities rised by32.68%~135.52%,and the uniformity of microbial speciesgreatly changed.The utilization ability of carbon source were studied and indicated that microbes preference for othertypes in Cd contaminated soil.The further analysis demonstrated that there was a significant difference in soil microbialmetabolic activities between the BCs treatment and the Cd control group,especially carboxylic acids and carbohydratescarbon source utilization.