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1.
三种城市景观竹土壤微生物群落结构特征   总被引:1,自引:0,他引:1  
付浩  曾歆花  宋志琳  兰思仁  黄卫昌 《土壤》2022,54(6):1165-1174
为探究城市景观竹林对土壤微生物群落的影响,选取上海辰山植物园种植的3种景观竹,利用Illumina MiSeq高通量测序结合土壤理化指标分析研究了不同景观竹林对土壤理化性质和微生物群落结构特征的影响。结果表明:不同竹林土壤全磷、有效磷、有机质、全氮、全钾含量和电导率存在显著差异(P<0.05);土壤细菌丰富度和多样性指数在毛竹林土壤中最高,在淡竹林土壤中最低;土壤细菌优势门为放线菌门(Actinobacteriota)、变形菌门(Proteobacteria)、酸杆菌门(Acidobacteriota)和绿弯菌门(Chloroflexi),真菌优势门为子囊菌门(Ascomycota),其中放线菌门和绿弯菌门在淡竹林土壤中的相对丰度最高,且显著高于其他竹林,而变形菌门、粘球菌门(Myxococcota)的相对丰度在毛竹林土壤中最高,土壤真菌优势门在不同竹林间的差异不显著。此外,土壤细菌群落结构和丰度受土壤p H、硝态氮、电导率、全磷、铵态氮、含水率、速效钾和微生物生物量碳影响显著,而真菌群落变化受全磷、电导率和全钾影响显著。  相似文献   

2.
三江源区土壤微生物和土壤养分空间分布特性研究   总被引:1,自引:0,他引:1       下载免费PDF全文
选取三江源地区玉树、沱沱河、隆宝、治多及多彩5个研究地,对其土壤微生物群落数量及土壤养分空间分布规律进行了分析研究,为我国高寒草地土壤生态系统多样性和系统变化数据提供科学依据。结果表明:不同土壤层(0~5、5~10和10~15 cm)土壤微生物群落数量表现为细菌放线菌真菌,且细菌数量占绝对优势;各研究地土壤微生物群落主要分布在土壤表层,其数量随土层深度的增加而减少;土壤微生物数量与土壤养分之间存在相关性,影响细菌数量的主要土壤因子是全钾、碱解氮、全氮及有效磷,影响放线菌数量的主要土壤因子是速效钾与全氮,影响真菌数量的主要土壤因子是p H值。  相似文献   

3.
研究了红壤茶园中不同树龄茶树根层土壤微生物区系分布和种群结构的变化及其生态学因子。结果表明 ,随着树龄的增长 ,茶树根层土壤的酸度增加 ,pH值下降 ,土壤交换性酸组成从交换性H 为主转变为以交换性Al3 为主 ;同时 ,土壤有机碳、可溶性酚总量和全氮含量随树龄而增加。细菌、放线菌以及微生物总量以树龄 1 0年的茶树根层土壤中数量最多 ,4 0年和 90年树龄的茶树根层土壤中的较接近 ;树龄 1 0年和 90年的茶树根层土壤中真菌数量相当 ,其大于 4 0年树龄的茶树根层土壤真菌数量 ;而芽孢杆菌数量以 4 0年树龄茶树根层土壤最多 ,而 1 0年和 90年树龄茶树的接近 ;茶树根层土壤微生物生物量碳随树龄增长而增加 ,但与茶树根层土壤可培养微生物总量无显著相关。茶树根层土壤微生物生物量碳与土壤pH、有机碳、可溶性酚和全氮分别呈显著 (p<0 0 5 )或极显著 (p<0 0 0 1 )相关。  相似文献   

4.
  【目的】  耕作措施对土壤健康和作物营养品质提升具有关键作用,明确不同耕作方式对土壤理化性质、微生物学特性及小麦营养品质的影响,为集约化农田可持续管理提供理论依据。  【方法】  田间试验自2012年起在山东德州进行,供试土壤为潮土,种植制度为小麦–玉米轮作。设置4种耕作模式处理:传统耕作、旋耕、休耕和免耕。2020年,采集0—20 cm土层土样分析土壤物理、化学性质和细菌群落结构,采集小麦籽粒样品分析其营养品质。  【结果】  与传统耕作相比,免耕、休耕和旋耕处理显著提高了土壤含水量、铵态氮、硝态氮、有机质、全氮及有效磷含量,休耕还显著提高了土壤容重,降低了土壤孔隙度。免耕、休耕和旋耕处理显著提高土壤微生物量碳、氮含量以及土壤细菌群落多样性指数,休耕及免耕处理提高土壤厚壁菌门(Firmicutes)、疣微菌门(Verrucomicrobia)的相对丰度,降低放线菌门(Actinobacteria)的相对丰度。从营养品质变化来看,休耕显著提高小麦籽粒蛋白质、淀粉、微量元素的含量,旋耕和免耕显著增加小麦籽粒蛋白质含量,除天冬氨酸外,其他16种氨基酸组分变化趋势与氨基酸总量变化基本一致。Pearson相关性分析及冗余分析(RDA)结果表明,小麦籽粒淀粉、铁、锌、硒含量与土壤含水量、铵态氮、硝态氮、有效磷、微生物量碳、微生物量氮均呈显著正相关关系,其中铵态氮(F=25.7,P=0.002)、微生物量碳(F=4.9,P=0.008)、全氮(F=3.3,P=0.028)、土壤pH (F=3.1,P=0.036)是影响小麦营养品质的主要环境因子。  【结论】  减少对土壤扰动的耕作方式可不同程度地改变土壤环境因子及细菌群落结构,与旋耕、免耕相比,休耕更有利于小麦籽粒蛋白质、淀粉、微量元素、氨基酸组分含量的积累,是改善土壤健康状况和提升小麦营养品质的有效耕作措施。  相似文献   

5.
土壤微生物群落结构对凋落物组成变化的响应   总被引:9,自引:0,他引:9  
凋落物分解是陆地生态系统养分循环的关键过程,明确凋落物多样性如何影响土壤微生物群落构成和多度,继而潜在地改变凋落物分解的微生物学机制有助于认识生物多样性和森林生态系统功能的关系。通过小盆模拟试验,应用磷脂脂肪酸谱图的方法研究了我国南方红壤丘陵区典型物种马尾松和湿地松的凋落物分别与白栎和青冈的凋落物混合,与单一针叶凋落物分解时相比,针阔混合凋落物分解过程中土壤微生物群落结构的变化,结果显示:(1)针阔混合凋落物分解时土壤微生物群落磷脂脂肪酸(Phospholipidfatty acids,PLFA)总量低于单一针叶处理,细菌和放线菌的相对多度高于单一针叶处理,真菌则相反,群落真菌/细菌低于单一针叶处理,土壤微生物生物量的差异主要来自于真菌;(2)主成分分析表明:针阔混合凋落物分解与单一针叶凋落物分解的土壤微生物群落结构差异显著,两个时期(分解9个月和18个月)主成分一分别可以解释65.74%和89.63%的变异,第一主成分主要包括18∶2ω6,9、18∶1ω9c、17∶0和10Me18∶0等磷脂脂肪酸;(3)土壤微生物群落结构受凋落物初始C/N和木质素/N调控,土壤微生物群落细菌的相对多度与凋落物初始C/N和木质素/N显著负相关,真菌则与凋落物初始C/N和木质素/N显著正相关,群落真菌/细菌与凋落物初始C/N和木质素/N显著正相关。针阔凋落物混合分解通过改变凋落物C/N和木质素/N,提供了对分解者更为有利的微环境。  相似文献   

6.
以不同退化梯度的高寒草地土壤为研究对象,研究草地退化对不同层次(0~10cm、10~20cm和20~30cm)土壤物理、化学和生物学特征的影响。结果表明:江河源区高寒生态条件下草地退化对土壤物理、化学和生物学性质具有相对一致的影响,随草地退化程度的加重,各土层土壤含水量和水稳性团聚体百分数逐渐下降,土壤容重则呈增加趋势。草地退化导致土壤各种营养物质含量(除全钾)、土壤微生物群落和土壤酶活性显著下降,其中土壤有机质、速效氮、过氧化氢酶、脲酶、磷酸酶、土壤细菌、真菌和微生物总量在0~10cm土层表现为未退化轻度退化中度退化重度退化,而土壤全氮、全磷、速效钾和放线菌数量在0~10cm土层表现为轻度退化未退化中度退化重度退化,在10~30cm土层,则表现为严重退化草地的有些指标有一定程度升高。相关性分析结果表明,各种土壤酶和微生物群落之间呈显著或极显著正相关(除土壤脲酶和中性磷酸酶之间无显著相关性外);土壤水分,容重、有机碳、全氮、速效氮、速效钾与各种土壤酶和各种微生物均具有显著相关性;水稳性团聚体与各种微生物和中性磷酸酶具有显著相关性。  相似文献   

7.
为探索秸秆还田与施肥方式2种农田措施对水稻-小麦(稻麦)轮作土壤微生物群落的影响,阐释其对土壤细菌和真菌群落结构和多样性的影响机制,本研究通过7年稻麦轮作长期定位监测试验,设置无肥空白(CK)、常规施肥(RT)、秸秆还田+常规施肥(RS)和秸秆还田+缓释肥(SS) 4个处理,采用Illumina Miseq高通量测序技术,分析土壤细菌和真菌群落结构和多样性,探索影响微生物群落的主控环境因子。结果表明, SS作物产量在2016年和2017年分别比RT显著提高11.6%和8.2%(水稻)、4.8%和3.6%(小麦),与RS无显著差异。相比RT,秸秆还田处理显著降低了土壤pH,提升了土壤有机碳和铵态氮含量;与RS相比,SS处理提高了铵态氮含量。秸秆还田处理提升了真菌群落多样性,但对细菌群落多样性无显著影响。SS与RS在细菌真菌群落多样性方面均无显著差异。相关性分析表明,细菌群落多样性与土壤pH呈负相关,与总氮含量呈正相关;真菌群落多样性则与土壤有机碳含量显著正相关。NMDS分析表明,施肥对于细菌群落结构影响较大(55.61%),真菌群落结构则对秸秆还田响应更明显(26.94%)。与RT相比,秸秆还田显著提升了细菌放线菌门、绿弯菌门、厚壁菌门的相对丰度,同时显著提升了真菌中子囊菌门的相对丰度,降低了担子菌门和接合菌门的相对丰度,加强了土壤碳氮循环能力并抑制了病原菌。SS与RS相比,仅提升了真菌中子囊菌门的相对丰度。综上,秸秆还田配施缓释肥有助于维持或者提高土壤养分有效性、作物产量及细菌真菌群落多样性,可以促进土壤碳氮循环。  相似文献   

8.
以山东蒙阴、莱州和栖霞3地老龄苹果园土壤为材料,分别在冬前和冬后采集0~30 cm(上层)与30~60 cm(下层)土层土样,探讨了冻融作用对老龄苹果园土壤微生物数量和酶活性的影响。结果显示:3地苹果园0~30 cm土层各理化性状均显著高于30~60 cm土层,其中速效钾含量差异最显著;冻融处理后,3地上下层土壤细菌、真菌和放线菌数量均显著性降低,且上层土壤降低最显著,其中蒙阴苹果园上层土壤细菌、真菌和放线菌分别降低了40.6%、43.6%和55.7%,3地上下层土壤细菌/真菌比值显著提高、尖孢镰孢菌基因拷贝数大幅下降;冻融处理后,3地上下层土壤脲酶、磷酸酶和蔗糖酶活性均有所降低,且表现出显著性差异,但三地上下层土壤CEC变化趋势不同,其中蒙阴苹果园上层CEC降低了41.7%,下层CEC提高了19.2%,栖霞苹果园则相反。综上,3地老龄苹果园土壤经过冻融处理后,显著降低了上下层土壤微生物数量,显著提高了上下层土壤细菌/真菌比值,优化了土壤微生物群落结构,有利于缓解苹果园连作障碍。  相似文献   

9.
为了解云南省菠萝蜜主要种植园土壤和叶片养分状况,以期为菠萝蜜园合理施肥提供依据。调查分析了云南省具有代表性的15个种植园不同土层(0~20、20~40、40~60 cm)的土壤养分状况和叶片养分含量,结合土壤养分分级标准,分析其相关性。结果表明:(1)土壤养分含量在0~20 cm土层含量最为丰富;不同土层间除土壤pH、有效硼之外,有机质及其他养分元素均有含量变幅范围、变异系数较大的表现。(2)86.67%土壤pH值小于6.5,土壤呈酸性,有机质、全氮、全钾、碱解氮、速效钾及各种中、微量元素含量中上水平,磷素含量各种植园表现不一,差异明显。(3)土壤有机质与土壤全氮呈极显著正相关关系;土壤全磷含量与土壤速效钾、有效锌、交换性钙呈极显著正相关关系,与有效磷、有效锰呈显著正相关关系;土壤pH与土壤交换性镁呈显著正相关关系,与叶片氮、锰、锌、铜呈显著负相关关系;叶片钙与土壤交换性钙呈显著正相关关系。因此,建议云南省菠萝蜜种植园施用石灰或者土壤调理剂提高土壤pH,增施有机肥、磷肥、硼肥,适当控制氮肥、钾肥、钙镁中量元素肥及铁锰铜锌微量元素肥的施入量,以达到平衡施肥的目的。  相似文献   

10.
秸秆覆盖下土壤养分与微生物群落关系研究   总被引:1,自引:0,他引:1  
以我国17省的85个土壤样品为研究对象,定量添加玉米秸秆置于30℃培养90d,研究处理后土壤有机质(SOM)含量及养分变化与微生物群落之间的关系。结果表明:土壤各理化指标除全氮、碱解氮、全磷含量在处理后部分土壤减少以外,全钾、速效钾、速效磷含量均显著增加;SOM变化差异显著,根据其变化量将土壤分为I_1组有机质增量(I)12.05g/kg,I2组0.25I9.0g/kg,I3组-112.3I-0.3g/kg。I_1和I_3组初始SOM含量高且相似,处理后SOM却出现显著增加和显著降低2种截然相反的结果,而初始SOM较低的I_2组增加,但不显著;初始可培养细菌远高于可培养真菌和放线菌,但处理后真菌增量显著高于细菌,I_3组最为明显;处理前后,I_2和I_3组部分土壤的微生物生物量碳(MBC)变化不显著,部分则显著下降,而I_1组MBC含量在处理后多为显著上升;磷脂脂肪酸(PLFA)测定结果表明I_2组土壤微生物受环境和养分胁迫较I_1和I_3组高,I_2组处理后MBC均值降低了10.3%。秸秆对土壤的添加效果除了受土壤本底养分等条件影响外,很大程度上决定于土壤原有微生物的类型和组成。PLFA可用于预测秸秆添加效果。  相似文献   

11.
Soil microbial communities are very sensitive to changes in land use and are often used as indicators of soil fertility. We evaluated the microbial communities in the soils of four types of vegetation (cropland (CP), natural grassland (NG), broadleaf forest (BF) and coniferous forest (CF)) at depths of 0–10 and 10–20 cm on the Loess Plateau in China using phospholipid fatty acid (PLFA) profiling and denaturing gradient gel electrophoresis (DGGE) of DNA amplicons from polymerase chain reactions. The soil microbial communities were affected more by vegetation type than by soil depth. Total organic carbon, total nitrogen, soil-water content, pH, bulk density (BD) and C:N ratio were all significantly associated with the composition of the communities. Total PLFA, bacterial PLFA and fungal PLFA were significantly higher in the BF than the CP. The DGGE analyses showed that NG had the most diverse bacterial and fungal communities. These results confirmed the significant effect of vegetation type on soil microbial communities. BFs and natural grass were better than the CFs for the restoration of vegetation on the Loess Plateau.  相似文献   

12.
Application of nanotechnology in agriculture has been expanded to improve crop production. The impact of nanomaterials (NMs) on factors that influence the survival and function of beneficial microorganisms is a less studied aspect that needs to be better understood. Only a few studies have assessed the effects of NMs on beneficial soil microorganisms. This study was conducted to assess the effects of nanofertilizer FertiGroe?N (FG-N) and nano-plant hormone HormoGroe?auxin (...  相似文献   

13.
研究了中国科学院红壤生态实验站长期定位施肥试验5种不同施肥处理对土壤pH、土壤交换性氢、铝的影响,及其与土壤有机质之间的相关性。结果表明,长期不同施肥处理均提高了土壤pH,降低了土壤交换性氢和交换性铝含量,改良了红壤的酸性。施用有机肥(M)、有机肥+菌剂(BM)、有机肥+菌剂+微量元素(BMT)显著优于施用化肥(F)和化肥+微量元素(TF)的处理。添加微量元素和有效菌剂后土壤交换性氢、铝含量略有提高。土壤有机质与土壤pH呈显著正相关,与土壤交换性氢含量的相关性不显著,而与土壤交换性铝含量呈显著负相关。随着土壤有机质含量的增加,土壤交换性氢占土壤交换性酸度比例越大。长期施用有机肥、提高土壤有机质含量是改良红壤酸度和减轻铝毒较好的农艺措施。  相似文献   

14.
The importance of assessing the impacts of soil arsenic (As) contamination on microbial properties lay on the fact that microbes are instrumental in nutrient cycling and are therefore indicators of soil quality. In this study, soil chemical extraction methods were used to extract labile and freely exchangeable As (water-soluble As and sodium bicarbonate-extractable As), amorphous/crystalline Fe and Mn oxide-bound As (acid ammonium oxalate-extractable As and hydroxylamine hydrochloride-extractable As), and their impacts on microbial biomass (microbial biomass C, total bacterial and fungal biomass, active bacterial and fungal biomass), enzyme activities representing four major soil biogeochemical cycles, i.e., C (β-glucosidase activity), N (urease activity), P (acid phosphomonoesterase activity), S (acryl-sulfatase activity), and microbial activity (fluorescein diacetate hydrolysis and dehydrogenase activity) were investigated in As-contaminated soils of Ambagarh Chauki block, Chhattisgarh, Central India. The results revealed that the majority of the As in soils resided in the Fe/Mn oxide-bound fraction. The microbial biomass C, total and active fungal biomass, and enzyme activities were significantly inhibited by all the forms of As. However, water-soluble As, even though occupying only a small portion of the total As (0.9–2.9 %), exerted the greatest impact. Interestingly, total and active bacterial biomass was not significantly affected by As toxicity, suggesting their resistance to As. Urease activity was not affected by As pollution.  相似文献   

15.
The changes of microbial biomass carbon (MBC) and nitrogen (MBN) and microbial community in the topsoil of the abandoned agricultural land on the semi-arid Loess Plateau in China during the natural succession were evaluated to understand the relationship between microbial community and soil properties. MBC and MBN were measured using fumigation extraction, and microbial community was analyzed by the method of fatty acid methyl ester (FAME). The contents of organic C, total N, MBC, MBN, total FAME, fungal FAME, bacterial FAME and Gram-negative bacterial FAME at the natural succession sites were higher than those of the agricultural land, but lower than those of the natural vegetation sites. The MBC, MBN and total FAME were closely correlated with organic C and total N. Furthermore, organic C and total N were found to be positively correlated with fungal FAME, bacterial FAME, fungal/bacterial and Gram-negative bacterial FAME. Natural succession would be useful for improving soil microbial properties and might be an important alternative for sustaining soil quality on the semi-arid Loess Plateau in China.  相似文献   

16.
Black soils (Mollisols) are one of the most important soil resources for maintaining food security in China, and they are mainly distributed in northeast China. A previous comprehensive study revealed the biogeographical distribution patterns of bacterial communities in the black soil zone. In this study, we used the same soil samples and analyzed the 454 pyrosequencing data for the nuclear ribosomal internal transcribed spacer (ITS) region to examine the fungal communities in these black soils. A total of 220,812 fungal ITS sequences were obtained from 26 soil samples that were collected across the black soil zone. These sequences were classified into at least 5 phyla, 20 classes, greater than 70 orders and over 350 genera, suggesting a high fungal diversity across the black soils. The diversity of fungal communities and distribution of several abundant fungal taxa were significantly related to the soil carbon content. Non-metric multidimensional scaling and canonical correspondence analysis plots indicated that the fungal community composition was most strongly affected by the soil carbon content followed by soil pH. This finding differs from the bacterial community results, which indicated that soil pH was the most important edaphic factor in determining the bacterial community composition of these black soils. A variance partitioning analysis indicated that the geographic distance contributed 20% of the fungal community variation and soil environmental factors that were characterized explained approximately 35%. A pairwise analysis revealed that the diversity of the fungal community was relatively higher at lower latitudes, which is similar to the findings for the bacterial communities in the same region and suggests that a latitudinal gradient of microbial community diversity might occur in the black soil zone. By incorporating our previous findings on the bacterial communities, we can conclude that contemporary factors of soil characteristics are more important than historical factor of geographic distance in shaping the microbial community in the black soil zone of northeast China.  相似文献   

17.

Purpose

Long-term fertilization can influence soil biological properties and relevant soil ecological processes with implications for sustainable agriculture. This study determined the effects of long-term (>25 years) no fertilizer (CK), chemical fertilizers (NPK) and NPK combined with rice straw residues (NPKS) on soil bacterial and fungal community structures and corresponding changes in soil quality.

Materials and methods

Soil samples were collected from a long-term field site in Wangcheng County established in 1981 in subtropical China between mid summer and early autumn of 2009. Terminal restriction fragment length polymorphism (T-RFLP) and the real-time quantitative polymerase chain reaction (real-time qPCR) of bacterial and fungal community and microbial biomass (MB-C, -N and -P) were analyzed.

Results and discussion

Redundancy analysis of the T-RFLP data indicated that fertilization management modified and selected microbial populations. Of the measured soil physiochemical properties, soil organic carbon was the most dominant factors influencing bacterial and fungal communities. The bacterial and fungal diversity and abundance all showed increasing trends over time (>25 years) coupling with the increasing in SOC, total N, available N, total P, and Olsen P in the fertilized soils. Compared to chemical fertilizer, NPKS resulted in the greater richness and biodiversity of the total microbial community, soil organic C, total N, MB-C, -N and -P. The high biodiversity of microbial populations in NPKS was a clear indication of good soil quality, and also indicated higher substrate use efficiency and better soil nutrient supplementation. Otherwise, unfertilized treatment may have a soil P limitation as indicated by the high soil microbial biomass N: P ratio.

Conclusion

Our results suggest that NPKS could be recommended as a method of increasing the sustainability of paddy soil ecosystems.  相似文献   

18.
Soil samples were collected in June and October from areas with three land-use types, i.e., Robinia pseudoacacia L. (RP), Caragana korshinskii Kom. (CK), and abandoned land (AL), of which the former two were afforested areas, whereas the latter was not. These areas were converted from similar farmlands 40 years prior. Illumina sequencing of 16S rRNA gene and fungal ITS gene was used to analyze soil bacterial and fungal diversity. Additionally, plant communities, soil properties, fine root biomass, and C, N, and P levels in fine root and microbial biomass were estimated. Compared to AL, the C:N:P stoichiometry in fine root and microbial biomass in the afforested lands was synchronously changed, especially the N:P ratio. Soil microbial diversities were affected by afforestation and were more related to N:P ratio than C:P and C:N ratios. Moreover, Alpha-proteobacteria, Gamma-proteobacteria, and Bacteroidetes were significantly more abundant in afforested soils than in the AL soil, and the abundances of Actinobacteria, Chloroflexi, Cyanobacteria, and Nitrospirae ranked as AL > RP or CK. For fungal taxa, Ascomycota abundance responded positively to afforestation, whereas Basidiomycota abundance responded negatively. Changes of soil microbial taxa were significantly correlated with the N:P ratio in fine root and microbial biomass, which explained 54.1 and 55% of the total variation in bacterial and fungal taxa, respectively. Thus, our results provide evidence that compositions of soil microbial communities are linked to the N:P ratio in the plant-soil system.  相似文献   

19.
Tree thinning and harvesting produces large amounts of slash material which are typically disposed of by burning, often resulting in severe soil heating. We measured soil chemical properties and microbial community structure and function over time to determine effects of slash pile burning in a ponderosa pine forest soil. Real time data were collected for soil temperature, heat flux, and soil moisture contents in one of two slash piles burned in April 2004. During the burn, soil temperatures reached 300 °C beneath the pile center and 175 °C beneath the pile edge. Slash pile burning increased soil pH, extractable N and P, and decreased total C levels within the first 15 cm of soil. Burning reduced soil bacterial biovolumes within the first 15 cm of soil and fungal biovolumes within the first 5 cm of soil. One month after the burn, soil microbial communities under the pile center were enriched in Gram-positive bacterial fatty acid markers compared to communities from under the pile edge and control (nonburned) soil. Fifteen months later, soil chemical properties had not returned to background levels, and microbial community structure in fire-affected soil, regardless of pile location, was distinct from communities of control soil. In fire-affected soil, concentrations of fungal fatty acid biomarkers were low and arbuscular mycorrhizal fungal biomarkers were absent, regardless of pile location. Slash pile burning also reduced fungal and bacterial respiration and resulted in large fluctuations in microbial potential N mineralization and immobilization activities. By altering soil properties important to soil conservation and plant reestablishment, slash pile burning negatively impacts forest ecosystems at localized scales.  相似文献   

20.
Soil micro-organisms play a vital role in grassland ecosystem functioning but little is known about the effects of grassland management on spatial patterns of soil microbial communities. We compared plant species composition with terminal restriction fragment length polymorphism (T-RFLP) fingerprints of soil bacterial and fungal communities in unimproved, restored and improved wet grasslands. We assessed community composition of soil micro-organisms at distances ranging from 0.01 m to 100 m and determined taxa–area relationships from field- to landscape level. We show that land management type influenced bacterial but not fungal community composition. However, extensive grassland management to restore aboveground diversity affected spatial patterns of soil fungi. We found distinct distance–decay and small-scale aggregation of fungal populations in extensively managed grasslands restored from former arable use. There were no clear spatial patterns in bacterial communities at the field-scale. However, at the landscape level there was a moderate increase in bacterial taxa and a strong increase in fungal taxa with the number of sites sampled. Our results suggest that grassland management affects soil microbial communities at multiple scales; the observed small-scale variation may facilitate plant species coexistence and should be taken into account in field studies of soil microbial communities.  相似文献   

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