Persistence of the herbicide butachlor in soil after repeated applications and its effects on soil microbial functional diversity

Effects of repeated applications of the herbicide butachlor (N-(butoxymethyl)-2-chloro -N-2′,6′-dimethyl acetanilide) in soil on its persistence and soil microbial functional diversity were investigated under laboratory conditions. The degradation half-lives of butachlor at the recommended dosage in soil were calculated to be 12.5, 4.5, and 3.2 days for the first, second, and third applications, respectively. Throughout this study, no significant inhibition of the Shannon-Wiener index H′ was observed. However, the Simpson index 1/D and McIntosh index U were significantly reduced (P ≤ 0.05) during the initial 3 days after the first application of butachlor, and thereafter gradually recovered to a similar level to that of the control soil. A similar variation but faster recovery in 1/D and U was observed after the second and third Butachlor applications. Therefore, repeated applications of butachlor led to more rapid degradation of the herbicide, and more rapid recovery of soil microorganisms. It is concluded that repeated butachlor applications in soil had a temporary or short-term inhibitory effect on soil microbial communities.     

Persistence of repeated triadimefon application and its impact on soil microbial functional diversity

The effects of repeated applications of the fungicide triadimefon in agricultural soil on the microbial functional diversity of the soil and on the persistence of the fungicide in the soil were investigated under laboratory conditions. The degradation half-lives of triadimefon at the recommended dosage, simulated by a first-order kinetic model, were 23.90, 22.95, and 21.52 days for the first, second, and third applications, respectively. Throughout this study, no significant inhibition of the Shannon-Wiener index (H′) was observed. However, the Simpson index (1/D) and the McIntosh index (U) were obviously reduced (p ≤ 0.05) during the initial 3 days after the first triadimefon application and thereafter, gradually recovered to or exceeded the level of the control soil. A similar trend in variation but with a faster recovery in the 1/D and U was observed after the second and third triadimefon applications, respectively. Taken together, the above results indicate that the repeated application of triadimefon enhanced the degradation rate of the fungicide and the recovery rate of the soil microbial functional diversity. It is concluded that repeated triadimefon applications in soil have a transient or temporary inhibitory effect on soil microbial communities.     

Influence of benomyl and prometryn on the soil microbial activities and community structures in pasture grasslands of Slovakia

The effects of pesticides (a herbicide and a fungicide) on the microbial community structure and their activity were analyzed in soil from four alpine pasture grasslands in Slovakia. Specifically, the effects of the herbicide, Gesagard (prometryn active ingredient), and fungicide, Fundazol 50 WP (benomyl active ingredient), on the microbial respiration activity (CO₂ production), the numbers of selective microbial physiological groups (CFU.g^?1) and the structure (relative abundance) of soil microbial communities [(phospholipid fatty acid (PLFA)] were analyzed under controlled laboratory conditions. All treatments including the treatments with pesticides increased (statistically significantly) the production of CO₂ in all fields during 21 days of incubation and posed a statistically insignificant negative influence on the numbers of the observed physiological groups of microorganisms. The significantly negative influence was evaluated only in the numbers of two physiological groups; spores of bacteria utilizing organic nitrogen and bacteria, and their spores utilizing inorganic nitrogen. A shift in the microbial composition was evident when the PLFA patterns of samples from different sites and treatments were compared by the Principal Component Analysis (PCA). According to the second component PCA 2 (15.95 %) the locations were grouped into two clusters. The first one involved the Donovaly and Dubakovo sites and the second one contained the Velka Fatra and Mala Fatra locations. The PLFA composition of the soils showed important changes after the treatment with pesticides according to PCA 1 (66.06 %). Other treatments had not had a significant effect on the soil microbial community with the exception of the population of fungi. The lower relative abundance (significant effect) of Gram-positive bacteria, actinomycetes and general group of bacteria were determined in samples treated by the herbicide Gesagard. The application of fungicide Fundazol decreased (statistically significantly) the relative abundance of actinomycetes and general group of bacteria and paradoxically increased the population of fungi.     

Effect of Dursban 480 EC (chlorpyrifos) and Talstar 10 EC (bifenthrin) on the physiological and genetic diversity of microorganisms in soil

This investigation was undertaken to determine the impact of the insecticides Dursban 480 EC (with organophosphate compound chlorpyrifos as the active ingredient) and Talstar 10 EC (with pyrethroid bifenthrin as the active ingredient) on the respiration activity and microbial diversity in a sandy loam luvisol soil. The insecticides were applied in two doses: the maximum recommended dose for field application (15 mg kg^?1 for Dursban 480 EC and 6 mg kg^?1 for Talstar 10 EC) and a 100-fold higher dose for extrapolation of their effect. Bacterial and fungal genetic diversity was analysed in soil samples using PCR DGGE and the functional diversity (catabolic potential) was studied using BIOLOG EcoPlates at 1, 3, 7, 14, 28, 56 and 112 days after insecticide application. Five bacterial groups (α, β, γ proteobacteria, firmibacteria and actinomycetes) and five groups of fungi or fungus-like microorganisms (Ascomycota, Basidiomycota, Chytridiomycota, Oomycota and Zygomycota) were analysed using specific primer sets. This approach provides high resolution of the analysis covering majority of microorganisms in the soil. Only the high-dose Dursban 480 EC significantly changed the community of microorganisms. We observed its negative effect on α- and γ-proteobacteria, as the number of OTUs (operational taxonomic units) decreased until the end of incubation. In the β-proteobacteria group, initial increase of OTUs was followed by strong decrease. Diversity in the firmibacteria, actinomycetes and Zygomycota groups was minimally disturbed by the insecticide application. Dursban 480 EC, however, both positively and negatively affected certain species. Among negatively affected species Sphingomonas, Flavobacterium or Penicillium were detected, but Achromobacter, Luteibacter or Aspergillus were supported by applied insecticide. The analysis of BIOLOG plates using AWCD values indicated a significant increase in metabolic potential of microorganisms in the soil after the high-dose Dursban application. Analysis of respiration demonstrated high microbial activity after insecticide treatments; thus, microbial degradation was relatively fast. The half-life of the active insecticide compounds were estimated within the range of 25 to 27 days for Talstar and 6 to 11 days for Dursban and higher doses stimulated degradation. The recommended dose levels of both insecticides can be considered as safe for microbial community in the soil.     

等温微量量热法研究石油污染对土壤微生物活性的影响

利用TAMⅢ等温微量量热仪研究不同浓度的石油污染对土壤微生物活性的影响。对大港油田不同石油污染程度的土壤样品（3683-5-1、西51-5、西15-14和8-13-6H-1）以及实验室配置的短时间内石油污染土壤（空白、0.5%、1.5%、2.5%和4.0%）进行了微量热检测。含油量升高,总放热量升高,生长速率常数降低,峰值功率先升高后降低,达到最大峰值功率的时间随着含油量的升高而延长。结果表明,石油污染会影响土壤微生物的活性,并且在低浓度时促进微生物的生长,石油浓度高时会抑制土壤中微生物的生长代谢。     

石油污染土壤的植物与微生物修复技术

石油污染土壤的生物修复技术具有成本低、简便高效、对环境影响小等优点,正逐步成为石油污染治理研究的热点领域,具有广阔的发展前景.介绍了我国的石油污染概况及生物修复技术在石油污染治理中的应用,重点对石油污染土壤的微生物修复、植物修复、植物一微生物联合修复技术的研究进展及各自的优点、局限性进行了综述,并提出了石油污染土壤生物修复技术研究的重点领域.     

Phylogenetic changes in soil microbial and diazotrophic diversity with application of butachlor

We investigated changes in population and taxonomic distribution of cultivable bacteria and diazotrophs with butachlor application in rice paddy soils. Population changes were measured by the traditional plate-count method, and taxonomic distribution was studied by 16S rDNA sequencing, then maximum parsimony phylogenic analysis with bootstrapping (1,000 replications). The bacterial population was higher after 39 than 7 days of rice cultivation, which indicated the augmentation of soil microbes by rice root exudates. The application of butachlor increased the diazotrophic population in both upper (0–3 cm) and lower (3–15 cm) layers of soils. Especially at day 39, the population of diazotrophs was 1.8 and 1.6 times that of the control in upper and lower layer soils, respectively. We found several bacterial strains only with butachlor application; examples are strains closest to Bacillus arsenicus, B. marisflavi, B. luciferensis, B. pumilus, and Pseudomonas alvei. Among diazotrophs, three strains closely related to Streptomyces sp. or Rhrizobium sp. were found only with butachlor application. The population of cultivable bacteria and the species composition were both changed with butachlor application, which explains in part the contribution of butachlor to augmenting soil nitrogen-fixing ability.     

SBR中SRT对总细菌群落结构的影响研究

为了揭示序批式反应器不同污泥停留时间(SRT)下总细菌群落结构的异同及SRT变化对总细菌群落结构的影响,应用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)进行研究。通过克隆测序发现,不同的SRT条件下生物多样性和种群结构会有所差异,既存在各SRT条件下相同的优势菌群(Escherichia coli和Aeromonas sp.),也存在某些SRT下特有的优势菌群(Uncultured Peptostreptococcaceae),SRT为40 d时检测到以降解硫酸盐获得能源的优势微生物。研究还表明,SRT为40 d时多样性指数取得最大值,各SRT条件下微生物的种群相似性差别较大。     

施用城市污泥堆肥对土壤微生物群落结构变化的影响简

在温室条件下进行了15周的盆栽实验,考察了施用城市污泥堆肥后,土壤中养分含量的变化规律,重点研究了施用城市污泥堆肥对土壤微生物群落结构变化的影响。实验发现,污泥堆肥能改善土壤养分,有机质和氮、磷含量得到显著提高。经PCR-DGGE分析,施肥1周后土壤中细菌和真菌的群落结构均发生了较大的变化。随着施肥时间的延长,细菌在富含有机质及氮、磷等养分的土壤环境下大量生长,多样性提高,其优势菌群属于γ变形菌、α变形菌和芽单胞菌;随着有机质的不断消耗,细菌的生长活性受到抑制,最终由于养分的缺乏,细菌种群多样性呈现小幅度的降低,优势菌群变为绿弯菌门、γ变形菌亚纲和厚壁菌门。对于真菌,其多样性指数在堆肥前3周逐渐提升,在第3~12周的监测中呈现相对稳定的变化趋势,优势菌群主要为座囊菌纲和散囊菌纲。     

水力停留时间对MBR中溶解性微生物产物生成的影响

考察水力停留时间(HRT)对MBR中膜污染的主要污染物——溶解性微生物产物(SMP)生成的影响。结果表明,在装置稳定运行期间,MBR中SMP随运行时间出现累积。与HRT为8 h相比,HRT为12 h时,SMP在MBR中平均累积量要少10.1%,SMP中多糖含量平均高7 mg/L左右,而蛋白质含量平均低45.6%。SMP的平均粒径随装置运行呈下降趋势,并且HRT较短有利于粒径较小的SMP生成,从而堵塞膜孔;HRT较长有利于粒径较大的SMP生成,从而形成凝胶层,两种情况导致膜污染的机制不同。     

施用城市污泥堆肥对土壤微生物群落结构变化的影响

在温室条件下进行了15周的盆栽实验,考察了施用城市污泥堆肥后,土壤中养分含量的变化规律,重点研究了施用城市污泥堆肥对土壤微生物群落结构变化的影响。实验发现,污泥堆肥能改善土壤养分,有机质和氮、磷含量得到显著提高。经PCR—DGGE分析,施肥1周后土壤中细菌和真菌的群落结构均发生了较大的变化。随着施肥时间的延长,细菌在富含有机质及氮、磷等养分的土壤环境下大量生长,多样性提高,其优势菌群属于γ变形菌、α变形菌和芽单胞菌;随着有机质的不断消耗,细菌的生长活性受到抑制,最终由于养分的缺乏,细菌种群多样性呈现小幅度的降低,优势菌群变为绿弯菌门、γ变形菌亚纲和厚壁菌门。对于真菌,其多样性指数在堆肥前3周逐渐提升,在第3～12周的监测中呈现相对稳定的变化趋势,优势菌群主要为座囊菌纲和散囊菌纲。     

Effects of methamidophos on the community structure,antagonism towards Rhizoctonia solani,and phlD diversity of soil Pseudomonas

A microcosm incubation study using an aquic brown soil from northeast China (a Cambisol in the UN Food and Agriculture Organization FAO Soil Taxonomy) was conducted to examine the effects of different concentrations (0, 50, 150, and 250 mg kg^?1) of methamidophos (O,S-dimethyl phosphoramidothioato) on Pseudomonas, one of the most important gram-negative bacteria in soil. Amplified ribosomal DNA restriction analysis (ARDRA) was performed to study the Pseudomonas community structure, an in vitro assay was made to test the antagonistic activity of isolated Pseudomonas strains against soil-borne Rhizoctonia solani, a major member of the pathogens highly related to soil-borne plant diseases, and special primer amplification and sequencing were performed to investigate the diversity of phlD, an essential gene in the biosynthesis of 2, 4-diacetylphloroglucinol (2, 4-DAPG), which has biocontrol activity in phlD ⁺isolates. With exposure to increasing methamidophos concentrations, the total number of soil Pseudomonas ARDRA patterns decreased significantly, but with less change in the same treatments over 1, 3, and 5 weeks of incubation. The number of isolated Pseudomonas strains with antagonistic activity against R. solani as well as the diversity and appearance frequency of the strains' phlD gene also decreased with increasing concentrations of methamidophos, especially at high methamidophos concentrations. Applying methamidophos could increase the risk of soil-borne plant diseases by decreasing the diversity of the soil Pseudomonas community and the amount of R. solani antagonists, particularly those with the phlD gene.     

进水碳负荷浓度对垂直潜流式人工湿地中植物根系微生物动态的影响

植物的不同生长发育阶段是影响根系微生物功能多样性的原因之一。植物的生长改变了微生物的群落结构。在低有机负荷或高有机负荷下,植物幼苗与成苗根系的微生物整体活性均差异明显,一般成苗期具有较高AWCD值。有植物湿地中微生物Simpson和Mcintosh多样性指数在植物成苗期均明显高于幼苗期(P0.05),但Shannon指数变化不明显(P0.05)。无植物湿地中微生物Simpson和Mcintosh指数受季节影响差异显著(P0.05)。主成分和聚类分析结果表明,不同生长发育阶段其微生物种类存在差异,而且不同进水条件下有植物湿地和无植物湿地各自有相似的微生物群体结构。     

Toxic effects of four sulphonylureas herbicides on soil microbial biomass

The effect of four triazinyl-sulfonylurea herbicides (cinosulfuron, prosulfuron, thifensulfuron methyl, triasulfuron) on soil microbial biomass, soil respiration, metabolic activity, metabolic quotient, and some enzymatic activities (acid and alkaline phosphatase, β-glucosidase, arylsulphatase, and fluorescein diacetate hydrolysis) were monitored under controlled conditions over 30 days. The herbicides were applied at the normal field dose (FD) and at ten-fold (10 FD) the field dose, in order to mimic a long term toxic effect. The measured soil microbial parameters showed that the FD had slight effects on soil microflora, while at 10 FD the tested herbicides exerted a stronger detrimental effect on soil microbial biomass and its biochemical activities.     

光合细菌改善Cd、Pb及呋喃丹污染土壤的微生物群落DNA序列多样性的研究

应用DNA随机扩增多态性(RAPD)分子标记技术研究了光合细菌(PSB)对Cd、Pb及呋喃丹污染土壤的微生物群落DNA序列多样性的影响.结果表明,Cd、Pb及呋喃丹单一污染或3者复合污染土壤的微生物群落DNA序列的丰富度相对对照土样(S0)都有不同程度的增加,受Cd、Pb或呋哺丹污染,可能会引起土壤微生物群落DNA序列...     

石油污染土壤中孤东原油及其馏分的微生物降解性能

分别以孤东油区石油污染土壤中的原油、柴油馏分(180～360℃)、蜡油馏分(360 ～ 500℃)为研究对象,采用BC-Ⅰ和BC-E 2种菌剂,对其进行微生物降解.研究表明,BC-Ⅰ和BC-E菌剂对石油污染土壤中石油烃的降解效果明显,BC-E菌剂对孤东油区石油污染土壤中石油烃的降解率达35.7％.2种菌剂对石油烃中轻馏分的降解效率均远远高于其对重馏分的降解效率.柴油馏分降解产物中鉴定出O1、O2、N1等多种分子类型,其中O2相对丰度远高于O1、N1类型,研究表明,该类化合物是脂肪酸,油样中脂肪酸存在明显的C16、C18优势,降解后低碳数脂肪酸相对丰度略有增加.蜡油(VGO)降解后以m/z=293(C19双环环烷酸)为中心正态分布,烷基咔唑中C5-咔唑丰度最高,苯并咔唑相对丰度很低.O2类化合物丰度很低,表明脂肪酸含量很低,DBE为4或5的O2类化合物明显占优势,对应3～4环环烷酸丰度较高.     

DGGE、T-RFLP 、LH-PCR对两种活性污泥的微生物种群多样性分析的比较

采用基于PCR扩增的分子生态技术DGGE、T-RFLP和LH-PCR,对2种典型污水处理系统中的活性污泥（生活污泥、焦化污泥）进行微生物种群多样性分析;并以此比较3种技术的优劣,提出不同应用条件下研究方法的选择依据。根据实验结果：DGGE得到的条带较多,但误差来源也最多;T-RFLP技术较为灵敏,但需要选择适当的内切酶,严格控制酶切条件,并且文库比对误差较大;而LH-PCR操作简单,结果稳定性较高。虽然目前尚无法判断3种方法的准确性,但LH-PCR在活性污泥的微生物种群多样性分析中已显示出潜在优势。     

污泥施用对根际和非根际石灰性土壤中细菌多样性的影响

为研究污泥施用对石灰性土壤细菌多样性的影响,在连续2年种植夏玉米大田系统中,施用不同量的腐熟污泥,采集根际和非根际土壤进行16S rDNA-V3-V4区高通量测序,分析污泥施用对石灰性土壤细菌丰富度、多样性指数、群落结构、功能基因在代谢途径的影响,同时对细菌群落和环境因素之间的相关性进行分析。结果表明：污泥用量分别在3.5～37.5 t·hm⁻²和3.5～7.5 t·hm⁻²有利于非根际和根际土壤OTU数量增加;但污泥在75 t·hm⁻²过量施用时,根际和非根际土壤细菌的Shannon多样性指数显著降低,Simpson指数显著增加,Ace,Chao丰富度指数显著降低。主成分和门水平物种丰度分析表明：污泥施用量不同会造成根际和非根际细菌群落结构差异,并且当污泥施用量为75 t·hm⁻²时,明显降低了非根际土壤放线菌门的丰度;污泥施用量在3.75～37.5 t·hm⁻²时,非根际土壤中拟杆菌门丰度会明显增加。与对照相比,当污泥用量为75 t·hm⁻²时,根际土壤拟杆菌门有明显的增加,增加丰度达1.45倍,但酸杆菌门和放线菌门丰度降低了49.74%和80.57%。冗余分析(RDA)表明,土壤TN、Cd、Cu、TP是影响土壤细菌群落最主要的因素,其中TN、Cd、Cu和细菌Shannon、Simpson多样性指数呈现显著相关性(P< 0.05)。由此可见,连续过量施入污泥会对根际和非根际石灰性土壤中细菌多样性造成不利影响,而且上述微生物多样性变化可作为污泥合理施用的判断依据。     

生物质对赤泥壤质化改良的促进作用

为解决赤泥的规模化安全处置问题,以拜耳法赤泥为研究对象,选用玉米秸秆为改良剂,通过分析各改良处理的基本理化指标、土壤酶活性以及微生物群落代谢水平等指标的变化,探究了生物质改良对赤泥壤质化改良的促进作用。结果表明,生物质添加可显著降低赤泥的盐碱性。其中,pH、电导率(EC)和盐碱度(Exchangeable sodium saturation percentage, ESP)分别降至9.89、0.461 mS·cm⁻¹和35.2%,且随添加比例的增加改良效果更佳。经生物质添加处理,赤泥基质容重显著降低、孔隙度显著增加,颗粒平均重量直径(Mean weight diameter, MWD)增加至0.38 mm。经生物质改良处理,赤泥中微生物群落的生长代谢水平、多样性以及土壤脲酶、磷酸酶和脱氢酶的活性均有显著升高。冗余分析(Redundancy analysis, RDA)结果表明,微生物群落多样性参数与pH、EC和ESP呈负相关,与MWD呈正相关。本研究结果可为赤泥规模化生态处理提供参考。     

阿特拉津土壤污染修复菌剂载体材料的筛选与应用

阿特拉津是长残留除草剂,其环境行为和生物修复技术已成为有机污染控制领域的研究热点。以廉价的高岭土、凹凸棒土和腐殖酸为载体材料,采用正交实验,把功能菌存活率作为目标性状,参考材料成球率,筛选出性能较好的高岭土、凹凸棒土和腐殖酸质量配比3种,分别为1∶0.5∶0.5(A3B2C1)、0.5∶0∶0.5(A2B3C1)和1∶0∶1(A3B1C2);在温度和紫外线耐受力实验中,A3B2C1材料配比更能够有效提升功能菌在高温和紫外线作用下的存活率,即载体中高岭土、凹凸棒土和腐殖酸质量比为1∶0.5∶0.5时效果最佳;利用A3B2C1载体材料配比制备菌剂,进行室内土壤修复实验,35 d时0.1%和0.5%载体菌剂添加量修复土壤中阿特拉津完全降解,而2个游离菌修复土壤中残留率均16%,0.1%载体菌剂添加量修复过程中土壤微生物Shannon多样性指数和均匀度变化幅度较其他修复方式小,有利于土壤微生物生态系统的平衡,因此0.1%载体菌剂添加量修复效果为最优。