Department of Plant & Microbial Biology, University of California at Berkeley, Berkeley, CA, USA.
Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científica (EEZ-CSIC), Granada, Spain.
Sci Rep. 2022 Jul 25;12(1):12690. doi: 10.1038/s41598-022-17075-5.
Biochar made-up of dry olive residue (DOR), a biomass resulting from the olive oil extraction industry, has been proposed to be used as a reclamation agent for the recovery of metal contaminated soils. The aim of the present study was to investigate whether the soil application of DOR-based biochar alone or in combination with arbuscular mycorrhizal fungi (AMF) leads to an enhancement in the functionality and abundance of microbial communities inhabiting metal contaminated soils. To study that, a greenhouse microcosm experiment was carried out, where the effect of the factors (i) soil application of DOR-based biochar, (ii) biochar pyrolysis temperature (considering the variants 350 and 500 °C), (iii) soil application dose of biochar (2 and 5%), (iv) soil contamination level (slightly, moderately and highly polluted), (v) soil treatment time (30, 60 and 90 days) and (vi) soil inoculation with Funneliformis mosseae (AM fungus) on β-glucosidase and dehydrogenase activities, FA (fatty acid)-based abundance of soil microbial communities, soil glomalin content and AMF root colonization rates of the wheat plants growing in each microcosm were evaluated. Biochar soil amendment did not stimulate enzyme activities but increased microbial abundances. Dehydrogenase activity and microbial abundances were found to be higher in less contaminated soils and at shorter treatment times. Biochar pyrolysis temperature and application dose differently affected enzyme activities, but while the first factor did not have a significant effect on glucosidase and dehydrogenase, a higher biochar dose resulted in boosted microbial abundances. Soil inoculation with F. mosseae favored the proliferation of soil AMF community and increased soil glomalin content as well as rates of AMF root colonization. This factor also interacted with many of the others evaluated to significantly affect soil enzyme activities, microbial abundances and AMF community. Our results indicate that the application of DOR-based biochar along with AMF fungi is an appropriate approach to improve the status of microbial communities in soils with a moderate metal contamination at short-term.
由橄榄残渣（DOR）制成的生物炭，是橄榄油提取工业的一种生物质，已被提议用作回收受金属污染土壤的改良剂。本研究旨在研究单独或与丛枝菌根真菌（AMF）联合施用 DOR 基生物炭是否会增强受金属污染土壤中微生物群落的功能和丰度。为此，进行了温室微宇宙实验，研究了以下因素的影响：（i）DOR 基生物炭的土壤施用，（ii）生物炭热解温度（考虑 350 和 500°C 的变体），（iii）生物炭的土壤施用量（2%和 5%），（iv）土壤污染水平（轻度、中度和重度污染），（v）土壤处理时间（30、60 和 90 天）和（vi）在每个微宇宙中接种摩西管柄囊霉（AM 真菌）对β-葡萄糖苷酶和脱氢酶活性、土壤微生物群落的 FA（脂肪酸）丰度、土壤胶蛋白含量和 AMF 根定殖率的影响。生物炭土壤改良剂并没有刺激酶活性，但增加了微生物丰度。在污染程度较低和处理时间较短的土壤中，脱氢酶活性和微生物丰度更高。生物炭热解温度和施用量对酶活性有不同的影响，但前者对葡萄糖苷酶和脱氢酶没有显著影响，而较高的生物炭剂量则导致微生物丰度增加。接种摩西管柄囊霉有利于土壤 AM 真菌群落的增殖，增加了土壤胶蛋白含量和 AMF 根定殖率。该因素还与评估的许多其他因素相互作用，显著影响土壤酶活性、微生物丰度和 AMF 群落。我们的结果表明，在短期内，将 DOR 基生物炭与 AMF 真菌一起应用是改善中度金属污染土壤中微生物群落状况的一种合适方法。
