Response of Microbial Communities in Soil to Multi-Level Warming in a Highland Barley System of the Lhasa River

Focusing on Sumatra, a hotspot of tropical lowland rainforest transformation, we investigated effects of the con- version of rainforests into rubber agroforests (Bjungle rubber^), intensive rubber, and oil palm plantations on the communities of litter and soil microorganisms and identified factors responsible for these changes. Litter basal respiration, microbial biomass, total bacterial phospholipid fatty acids (PLFAs), and fungal PLFAs did not vary significantly with rainforest conversion. In litter of converted ecosystems, the concentration of certain PLFAs including the Gram-negative bacteria marker PLFA cy17:0 and the Gram-positive bacteria marker PLFA i17:0 was reduced as compared to rainforest, whereas the concentration of the arbuscular mycorrhizal fungi (AMF) marker neutral lipid fatty acid (NLFA) 16:1ω5c in- creased. As indicated by redundancy analysis, litter pH and carbon concentration explained most of the variation in litter microbial community composition. In soil, microbial biomass did not vary significantly with rainforest conversion, whereas basal respiration declined. Total PLFAs and especially that of Gram-negative bacteria decreased, whereas PLFA i17:0 in- creased with rainforest conversion. The concentration of fun- gal PLFAs increased with rainforest conversion, whereas NLFA 16:1ω5c did not change significantly. Redundancy analysis indicated that soil pH explained most of the variation in soil microbial community composition. Overall, the data suggest that conversion of rainforests into production systems results in more pronounced changes in microbial community composition in soil as compared to litter. In particular, the response of fungi and bacteria was more pronounced in soil, while the response of AMF was more pronounced in litter. Notably, only certain bacterial markers but not those of saprotrophic fungi and AMF were detrimentally affected by rainforest conversion.

Changes in vegetation types affect soil microbial communities in tropical islands of southern China

Many studies have shown the simulated effects of nitrogen (N) deposition on soil microbial community composition by adding N directly to the forest floor but have ignored the N retention process by the canopy. This study was conducted to compare the responses of soil microbial biomass and community composition between soil application of N (SAN) and foliage application of N (FAN). A pot experiment was designed with (1) two N application methods (SAN and FAN), (2) three N application levels (5.6, 15.6 and 20.6 g N m−2 year−1), and (3) two tree species (Schima superba Gardn. et Champ. and Pinus massoniana Lamb.) following a nested factorial design. Soil microbial biomass and community composition were determined using phospholipid fatty acids (PLFAs) techniques after 1 and 1.5 years of treatments. Nitrogen addition increased (P < 0.05) soil NH4+-N content and soil NO3−-N content and decreased (P < 0.05) soil pH and soil microbial (bacterial, fungal, and actinomycete) biomass for both N application methods. Compared with the SAN treatment, the FAN treatment had higher (P < 0.05) pH and lower (P < 0.05) contents of soil NH4+-N and soil NO3−-N. Soil microbial biomass and community composition were significantly different between the different N addition levels under the SAN treatment, but they showed no significant difference (P < 0.05) between the different N addition levels under the FAN treatment. The soil microbial biomass in the S. superba soil was higher (P < 0.05) than that in the P. massoniana soil for the FAN treatment, with the opposite trend observed under the SAN treatment. Moreover, redundancy analysis showed that soil microorganisms were significantly correlated with soil pH, soil water content, NH4+-N, and NO3−-N. The results showed that N addition affected soil properties, microbial biomass, and the composition of microbial communities; however, the FAN treatment had less influence on soil properties and soil microorganisms than did the SAN treatment over short time scales, and the extent of this effect was different between coniferous and broadleaf trees.

ABSTRACTPoplar trees (Populus spp.) are often used in bioremediation strategies because of their ability to phytoextract potential toxic ions, e.g., selenium (Se) from poor quality soils. Soil microorganisms may play a vital role in sustaining health of soil and/or tolerance of these trees grown in poor quality soils by contributing to nutrient cycling, soil structure, overall soil quality, and plant survival. The effect of naturally occurring salts boron (B) and Se on soil microbial community composition associated with poplar trees is not known for bioremediation strategies. In this study, three Populus clones 13–366, 345–1, and 347–14 were grown in spring 2006 under highly saline, B, and Se clay-like soils in the west side of the San Joaquin Valley (SJV) of CA, as well as in non-saline sandy loam soils located in the east side of the SJV. After 7 years of growing in the respective soils of different qualities, soil samples were collected from poplar clones grown in saline and non-saline soils to examine and compare soil quality effects on soil microbial community biomass and composition. The phospholipid fatty acid (PLFA) analysis was used to characterize microbial community composition in soils from trees grown at both locations. This study showed that microbial biomass and the amount and proportion of arbuscular mycorrhizal fungal (AMF) community were lower in all three poplar clones grown in saline soil compared to non-saline soil. Amounts of Gram + bacterial and actinomycetes PLFAs were significantly lower in poplar clone 13–366 grown in saline soil compared to non-saline soil; however, they did not differ significantly in poplar clones 347–14 and 345–1. Additionally, amounts of saprophytic fungal, Gram − bacterial and eukaryotic PLFA remained similar at saline and non-saline sites under poplar clones 347–14, 345–1, and 13–366. Therefore, this study suggested that salinity and B do have an impact on microbial biomass and AMF; however, these poplar clones still recycled sufficient amount of nutrients to support and protect saprophytic fungal and bacterial communities from the effects of poor quality soils.

Human activities have significantly increased nitrogen (N) and phosphorous (P) inputs to terrestrial ecosystems. However, the impact of N and P enrichment on soil microbial community structure and functioning in temperate and alpine grassland ecosystems remains unclear. In this study, we investigated the responses of soil microbial communities to nutrient (N and P) additions in two temperate and one alpine grassland ecosystems in China. We measured soil chemical properties, microbial community composition (indicated by the phospholipid fatty acids, PLFA) and potential enzyme activities related to carbon (C), N, and P cycling in the peak growing season after 4 years of nutrient addition. We found that N addition reduced soil pH and increased soil total N content at two meadow sites, P addition increased soil total P content at all three sites, but both N and P additions had minimal effects on soil organic C content. Bacteria and total microbial abundances did not change after N and P additions, while fungi and arbuscular mycorrhizal fungi (AMF) abundances were suppressed by N addition. Moreover, the activity of soil extracellular enzymes involved in C, N and P cycling and their stoichiometric ratios were not responsive to N and P additions, except for inhibition of acid phosphatase by P addition at the temperate meadow site. Despite significant changes in soil chemistry (e.g., pH and available nutrients), soil microbial biomass (except fungi and AMF abundances), community structure, and enzyme activities (except phosphatase) were generally resistant to 4 years of N and P addition in the three temperate and alpine grassland ecosystems in China.

Transition of populations from rural to urban living causes landscape changes and alters the functionality of soil ecosystems. It is unclear how this urbanization disturbs the microbial ecology of soils and how the disruption influences nitrogen cycling. In this study, microbial communities in turfgrass-grown soils from urban and suburban areas around Xiamen City were compared to microbial communities in the soils from rural farmlands. The potential N2O emissions, potential denitrification activity, and abundances of denitrifiers were higher in the rural farmland soils compared with the turfgrass soils. Ammonia oxidizing archaea (AOA) were more abundant than ammonia oxidizing bacteria (AOB) in turfgrass soils. Within turfgrass soils, the potential nitrification activities and AOA abundances were higher in the urban than in the suburban soils. These results indicate a more pivotal role of AOA in nitrification, especially in urban soils. Microbial community composition was distinctly grouped along urbanization categories (urban, suburban, and rural) classified according to the population density, which can in part be attributed to the differences in soil properties. These observed changes could potentially have a broader impact on soil nutrient availability and greenhouse gas emissions.

ABSTRACTPinus yunnanensis var. Tenuifolia is an important species of timber and grease in southern China, but the characteristics of the soil microbial community in P. yunnanensis var. natural secondary forests are still poorly understood. Using a fumigation-extraction method and phospholipid fatty acid (PLFA) analysis, we study microbial biomass and community composition in the topsoil (0–10 cm) of three types of secondary forests (PYI, PYII, PYIII) dominated by P. yunnanensis var. to varing degrees. Microbial biomass carbon and nitrogen, total PLFA, and PLFA contents of bacterial, fungal, and arbuscular mycorrhizal fungi were significantly lower in PYI than PYII or PYIII, and there were significant differences in the monounsaturated/saturated fatty acid ratio among the tested forests. Principal component analysis indicated that the soil microbial community structure of the tested forests differed significantly. The changes in soil microbial biomass and community composition were positively correlated with soil water content, pH, organic matter (SOM), total nitrogen (TN), and total phosphorus. Season did not significantly affect the soil microbial community structure, but significantly affected soil microbial biomass, SOM, and TN, which were higher in the dry season than in the wet season.

Effect of two broad-spectrum fungicides on the microbial communities of a soil subjected to different degrees of water erosion

Summary Although the effect of experimental warming on soil microorganisms has been well documented at surface horizons, less is known about its influence in subsurface horizons. An experiment was therefore carried out in an alpine meadow on the Q inghai‐ T ibet P lateau to examine the responses of microbial communities to experimental warming at five soil depths (0–10, 10–20, 20–30, 30–40 and 40–50 cm). Plots were passively warmed for 3 years in open‐top chambers and compared with adjacent control plots at ambient temperature. Soil microbial communities were assessed by using phospholipid fatty acid ( PLFA ) analysis. Our results showed clearly that 3 years of experimental warming increased microbial biomass consistently and significantly throughout the upper 50‐cm soil profiles, as indicated by the changes in both microbial biomass carbon ( C ) and total PLFA contents. The composition of microbial communities was also affected significantly by warming, but its effect depended on soil depth. While warming induced a community shift towards bacteria at the 0–10‐cm depth, it tended to shift microbial communities towards fungi at the other, deeper, layers. These results indicate that warming had strong effects on soil microbial communities, including even those residing in subsurface horizons, which may help us to understand the microbial mediation of the feedback between terrestrial C cycling and climate warming.

oil microbes are important for many underground ecological processes and the change in their total biomass and community structure is regarded as a sensitive indicator for climate warming and human disturbances.Through open top chambers(OTCs) warming and clipping plus dung application,the effects of warming and grazing on soil microbial biomass and community structure were determined in an alpine meadow on the eastern Qinghai-Tibetan Plateau.The profiles of microbial phospholipid fatty acids(PLFAs) showed that soil microbial communities were dominated by bacteria in the growing seasons.An increase of 1.17 ℃ by OTCs warming soil at 10 cm depth resulted in a rise of 34.58% of total PLFAs,while the clipping plus dung application in spring caused a rise of 65.77%.Both experimental warming and grazing led to a significant change in soil microbial community structure.Compared to the control treatment,OTCs warming increased bacterial PLFAs by 8.80% and decresaed fungal PLFAs by 17.48%.The ratio of bacteria to fungi changed from 7.3 to 9.6.Grazing also markedly increased bacterial PLFAs by 8.40% and decreased fungal PLFAs by 14.04%.The ratio of bacteria to fungi increased to 9.2.The effects of OTCs warming and grazing on soil microbial biomass and community structure were found more notable than those of OTCs warming or grazing alone.Our results suggest that climatic warming and human disturbances might cause significant changes in soil microbial communities in a short period of time,which could have important effects on carbon budget and nutrient cycling in the alpine meadow ecosystem in the eastern Qinghai-Tibetan Plateau.

With continuous increases in nitrogen (N) deposition in the future, its impacts on terrestrial ecosystems are attracting growing concern. Arbuscular mycorrhiza (AM) fungi play a crucial role in shaping both soil microbial and plant communities. AM fungi play a crucial role in shaping the soil microbial and plant communities, yet their patterns of influence under increased N deposition scenarios remain unclear, particularly in desert ecosystems. Therefore, we conducted a field experiment simulating increased N deposition and AM fungal suppression to assess the effects of increased N deposition and AM fungi on soil microbial communities, employing phospholipid fatty acid (PLFA) biomarker technology in the Gurbantunggut Desert of Xinjiang. We found that increased N deposition promoted soil microbial biomass, including AM fungi, fungi, Actinomycetes (Act), Gram-positive bacteria (G+), Gram-negative bacteria (G−), and Dark Septate Endophyte (DSE). AM fungal suppression significantly increased the content of soil Act and G+. There were clearly and significantly interactive effects of increased N deposition and AM fungi on soil microbial contents. Both increased N deposition and AM fungi caused significant changes in soil microbial community structure. Random forest analysis revealed that soil nitrate N (NO3−-N), Soil Organic Carbon (SOC), and pH were main factors influencing soil microorganisms; soil AM fungi, G+, and Act significantly affected plant Shannon diversity; soil G−, Act, and fungi posed significant effects on plant community biomass. Finally, the structure equation model results indicated that soil fungi, especially AM fungi, were the main soil microorganisms altering the plant community diversity and biomass under increased N deposition. This study reveals the crucial role of AM fungi in regulating soil microbial responses to increased N deposition, providing experimental evidence for understanding how N deposition affects plant communities through soil microorganisms.

For an alkaline–saline region in Northwest China, we examined the responses of soil microbial communities to flue gas desulfurization gypsum by-products (FGDB), a new ameliorant for alkaline–saline soils. In 2009 and 2010, we collected soils from 0–20 cm and 20–40 cm depths along an experimental FGDB gradient (0, 0.74, 1.49, 2.25, and 3.00 kg FGDB m−2). As a measure of microbial community composition and biomass, we analyzed phospholipid fatty acids (PLFAs). We used real-time quantitative polymerase chain reaction (qPCR) to measure abundance of bacterial 16 S rRNA copy numbers. Additionally, physicochemical soil parameters were measured by common laboratory methods. Microbial community composition differed along the FGDB gradient; however, the microbial parameters did not follow a linear response. We found that, in 2009, total PLFA concentrations, and concentrations of total bacterial and Gram-negative bacterial PLFAs were slightly higher at intermediate FGDB concentrations. In 2010, total PLFA concentrations, and concentrations of total bacterial, Gram-positive bacterial, Gram-negative bacterial, and fungal PLFAs as well as the fungal:bacterial PLFA ratio were highest at 1.49 kg FGDB m−2 and 3.00 kg FGDB m−2. PLFA concentrations often differed between 2009 and 2010; however, the patterns varied across the gradient and across microbial groups. For both years, PLFA concentrations were generally higher at 0–20 cm depth than at 20–40 cm depth. Similar results were obtained for the 16 S rRNA copy numbers of bacteria at 0–20 cm depth. FGDB addition resulted in an increase in soil Ca2+ and NO 3 − –N and a decrease in pH and electrical conductivity (EC). Shifts in PLFA-based microbial community composition and biomass could partly be explained by pH, soil organic carbon, total nitrogen (TN), soil moisture, EC, inorganic nitrogen, C/N, and Ca2+. Indirect effects via shifts in abiotic soil properties, therefore, seem to be an important pathway through which FGDB affect soil microbial communities. Our results demonstrate that addition of FGDB leads to significant changes in soil physicochemical and microbial parameters. As such, addition of FGDB can have large impacts on the functioning of soil ecosystems, such as carbon and nitrogen cycling processes.

PDF HTML阅读 XML下载 导出引用 引用提醒 马尾松林土壤微生群落结构对不同营林处理的响应 DOI: 10.5846/stxb201707131275 作者: 作者单位: 中国林业科学研究院森林生态环境与保护研究所 国家林业局森林生态环境重点实验室 南京林业大学南方现代林业协同创新中心,中国林业科学研究院森林生态环境与保护研究所 国家林业局森林生态环境重点实验室 南京林业大学南方现代林业协同创新中心,中国林业科学研究院森林生态环境与保护研究所 国家林业局森林生态环境重点实验室 南京林业大学南方现代林业协同创新中心,中国林业科学研究院森林生态环境与保护研究所 国家林业局森林生态环境重点实验室 南京林业大学南方现代林业协同创新中心,中国林业科学研究院森林生态环境与保护研究所 国家林业局森林生态环境重点实验室 南京林业大学南方现代林业协同创新中心,中国林业科学研究院森林生态环境与保护研究所 国家林业局森林生态环境重点实验室 南京林业大学南方现代林业协同创新中心,湖北省秭归县国有九岭头林场 作者简介: 通讯作者: 中图分类号: 基金项目: 中央级公益性科研院所基本科研业务费专项（CAFYBB2016SY015，CAFYBB2016SY013） Soil microbial community structure of Pinus massoniana forest under various forest management practices Author: Affiliation: Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, State Forestry Administration Key Laboratory of Forest Ecology and Environment;Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University,Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, State Forestry Administration Key Laboratory of Forest Ecology and Environment;Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University,Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, State Forestry Administration Key Laboratory of Forest Ecology and Environment;Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University,Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, State Forestry Administration Key Laboratory of Forest Ecology and Environment;Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University,Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, State Forestry Administration Key Laboratory of Forest Ecology and Environment;Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University,Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, State Forestry Administration Key Laboratory of Forest Ecology and Environment;Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University,Jiulingtou State-owned Forest Farm of Zigui County， Hubei Province Fund Project: Fundamental Research Funds of RIFEEP 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以不同营林处理措施（对照、除灌、采伐1（15%）、采伐2（70%）后不同时期（处理后2个月，2013年12月；处理后15个月，2014年12月）三峡库区马尾松飞播林为研究对象，采用磷脂脂肪酸分析法对其土壤微生物生物量、微生物群落结构进行测定，同时比较了不同处理土壤理化性质特征，结果表明：1）处理后1年，除丛枝菌根真菌外，除灌、采伐1和采伐2微生物群落各类群生物量以及总生物量与对照相比均呈现减少的趋势，而在处理后初期并无规律性变化；2）主成分分析表明（PCA）不同处理措施在实施后初期并未对微生物群落结构产生显著影响，而在处理后1年，除灌和采伐1、采伐2的微生物群落结构显著区别于对照，且与土壤微生物群落多样性相关的2个主成分分别解释变量变化的50.40%和26.70%；3）2013年真菌生物标记（20：1 w9c）与主成分1极显著相关，而在2014年与主成分1极显著相关的生物标记物变为革兰氏阴性细菌（16：1w7c）；4）冗余度分析表明，土壤湿度、土壤温湿度比值、土壤微生物熵（微生物量碳（MBC）/土壤有机碳（SOC））是影响不同时期微生物群落结构的显著环境因子（P < 0.05）。 Abstract:Soil microorganisms can make up more than 95% of the total soil biomass, and plays important role in decomposition of carbon sources and organic matter. Forest management practices (e.g., harvesting, burning, and thinning) influence the composition of the soil microbial community by affecting habitat and substrate for soil microorganisms directly and indirectly, and hence affect soil carbon process. Quantifying the responses of the soil microbial community to forest management is vital to accurately evaluate forest carbon balance and to reveal the underlying mechanisms of soil carbon process change. Thus, an aerially seeded Pinus massoniana forest was chosen in the Three Gorges reservoir area to evaluate the effects on soil microbial community owing to different forest management practices (i.e., control; shrub-removal:harvesting all shrubs and removing all harvest residues. Harvest strategy 1:15% harvest intensity and removing main harvest residues without leaves and small branches; Harvest strategy 2:70% harvest intensity and the same harvest residue management as that in harvest 1). All experimental treatments were located in similar habitats and consisted of three 20 m×20 m plots. The treatments were conducted in October 2013, and soil samples were collected in December 2013 (2 months post treatments) and December 2014 (12 months post treatments) to analyze soil microbial community by using phospholipid fatty acid (PLFA) methods, and analyze soil chemical properties. The results showed that the total microbial biomass and biomass of all microbial species (except arbuscular mycorrhizal fungi) in shrub-removal, harvest strategy 1 and harvest strategy 2 were lower than those of the control in December 2014. However, there was no consistent rule observed in December 2013. Principal component analysis indicated that all treatments showed no significant change in soil microbial community structure in December 2013; the 2 principal component factors related to microbial community diversity explained 60.90% and 17.40% of the variation respectively. Shrub-removal, harvest strategy 1 and harvest strategy 2 did significantly affect soil microbial community structure in December 2014, and the 2 principal component factors related to microbial community diversity explained 50.40% and 26.70% of the variation respectively. In 2013, 5 PLFAs (Mel 16:0, 16:1w5c, 16:1w7c, al17:0 and 20:1w9c) played a major role in the first principal component, and 7 PLFAs (Mel16:0, 16:1w5c, 14:0, 16:0, cy17:0, 16:1w7c, i14:0) played a major role in the first principal component in 2014. The fungi (20:1w9c) PLFAs played the most significant role in the first principal component in 2013 and was replaced by gram negative bacteria (16:1w7c) PLFAs in 2014. Soil moisture, ratio of soil temperature and soil moisture, and soil microbial quotient (ratio of soil microbial biomass carbon and soil organic carbon) were significant factors regulating soil microbial community structure at different treatment times (P < 0.05), as revealed by redundancy analysis (RDA). 参考文献 相似文献 引证文献

Changes in soil microbial biomass and community composition in coastal wetlands affected by restoration projects in a Chinese delta

Within the framework of sustainable agriculture, the integrated rice-snail-crayfish farming system has been recognized as a highly efficient agroecological approach that enhances crop production while minimizing the application of chemical fertilizers and pesticides. Nonetheless, the mechanisms by which this system influences soil microbial community composition to achieve these benefits remain unknown. In this study, we focused on traditional rice farming (TR), the integrated rice-snail-crayfish (R-S-C) farming system, and mono-rice farming (CK), and systematically examined the impacts of these farming systems on soil chemical properties, microbial biomass, enzyme activity, and microbial community composition. Our results showed that the R-S-C significantly increased soil pH, microbial biomass carbon (MBC), and the MBC/microbial biomass phosphorus (MBP) ratio compared to TR, as well as the peroxidase activity. Moreover, the R-S-C significantly increased soil total phospholipid fatty acid (PLFA), bacterial PLFAs, Gram-negative bacterial (GN) PLFAs, anaerobic bacteria PLFAs, arbuscular mycorrhizal fungi (AMF) abundances, and the bacteria/fungi ratio compared to the other two systems. However, the soil microbial α-diversity indices, including Shannon–Wiener index (H), Simpson index (D), and Pielou evenness index (J), were significantly lower in the R-S-C system than in the other two systems. Further exploration suggested that soil pH, microbial biomass nitrogen (MBN), the MBN/total nitrogen (TN) ratio, and the MBC/MBP ratio were critical factors governing microbial community composition under the three farming practices. Notably, soil pH alone accounted for 64.5% of the observed variation in microbial community composition. Path analysis using partial least squares structural equation modeling further revealed the pathways by which the R-S-C system enhanced total PLFAs, AMF, and gram-positive bacteria by regulating the soil pH and MBN/TN ratio. This study provides insights into the regulatory mechanisms driving soil microbial communities in the R-S-C system and offers a theoretical foundation for developing sustainable agricultural management practices.