我们感谢美国凯斯西储大学的乡绅Valleevue和谷岭农场，包括A. LOCCI，C.债券，和A. Alldridge，帮助建立公共花园。 J.挂钩，L.霍夫曼，L.冈萨雷斯，资深大律师莱希，B. Ochocki，A. Ubiles，三宇，十赵，和NM齐默尔曼提供现场协助。 AJB和JHB由启动资金来自凯斯西储大学到JHBGAD资助是由暑期课程在本科生科研津贴从凯斯西储大学的霍华德·休斯医学研究所的资助支持。这项工作也是由美国国家科学基金会的资助，以JHB（DEB 1250170）的支持。

1。收集现场土壤，产生异构和同构土壤处理<ol><li>识别两个cooccurring植物类似的栖息地和土壤类型的研究（ 例如 图1a）。确定的量的土壤需要根据土壤的贴片尺寸的实验（ 例如三分之一到二分之一的焦点物种的初生根区域或体积由根球包含的）和实验所需的补丁的数量使用（参见方案2和3，下面）。 <ol><li>对于鲁梅克斯属。 （ 图1a），使用10厘米土壤斑块×10cm的x 18厘米（长x宽x深）为10厘米半径从植物的基部至18厘米深的近似根区（5655厘米3个土从这个定义中区一个单独的植物根系产生影响1,800 立方厘米 ）3土壤斑块。 </li></ol></li><li>调查野外现场找到两个重点物种的成年个体。避免个人的袋鼠T区可能重叠与其他重点物种（位于内的其他物种为0.25m 如鲁梅克斯个人）。标记需要获得所需的土壤的量与针标志的个体的数量。 <ol><li>马克20随机选择各酸模属的个体。 20试点单位（2种×2土壤处理×5个重复），每个需要来自各重点品种3个土补丁（如在协议2，下图）。 </li></ol></li><li>消毒土壤采集设备（铁锹，手套，运输容器）用漂白剂的约1点10分混合物（5-10％次氯酸钠）和水以去除所有土壤颗粒。使用前干燥设备，以避免对土壤生物漂白效果。标签每件设备与实验室磁带指示重点物种，其土壤它将收集或运输，以避免交叉污染（ 如标签1铲物种A和第二铲物种B）。 </li><li>检查天气和土壤条件土壤开始收集近期降水事件之前，系统蒸发散。避免收集土壤过于潮湿（泥泞或完全饱和），或在降雨事件，以减少土壤板结采集土壤。避免收集土壤过于干燥（非常坚硬，不易插入铲进）从根部土壤中分离到帮助。 </li><li>收集田间土壤从两个焦点物种的重复分批个人标记，以避免pseudoreplication（ 例如含有一种罕见的致病菌整个实验重复随后被混合的一个土壤样品）。 <ol><li>挖种A（定义见步骤1.1）与适当标记的无菌铲，从与适当标记的无菌手套土壤去除可见的粗根，然后将土壤中的适当标记的个体的完整的根区无菌运输容器（ 如桶）。对于实验4实验台，每个块和1株的根区提供足够的土壤1实验装置（如第1.2.1节），重复此过程物种A的另外3个人</li><li>物种B。重复第1.5.1节</li><li>从两个物种传递复制的土壤收集到的实验场地。放置在土壤实验单位为实验的块1（如在方案2或3，下图），其中一个块中包含从每个处理组合的实验单元（ 即各物质X的每个土壤处理）。 </li><li>重复第1.5.3节。 </li><li>在实验中剩余的数据块重复第1.5.1-1.5.4。从个人团体至少1米以前每次采集地点遥远的复制项目的集合，以尽量减少pseudoreplication收集的土壤。 </li></ol></li></ol><img alt="图1" fo:content-width="6in" src="/files/ftp_upload/51580/51580fig1highres.jpg" width="500" /> FIGUR区1。实例字段的实验设计操纵植物诱导土壤的异质性。（ 一 ）土壤是从同种（α）和heterospecifics（β）中的字段的根影响的区域收集，下列标准协议用 ​​于研究植物的土壤的效果进行反馈9 。 （b）与来自植物A（α土壤）土壤组成的非均匀土壤和植物乙（&#39;β&#39;土）土的试验治疗是排列在网格中，并与来自这两个来源的土壤的等量混合物中创建均质土壤处理。在这个例子中，字段的土壤栅格插入凹陷入地面的大直径盆和每个网格周围的区域填充有粗，灭菌砂。这个数字已经被修改勃兰特等人 10 2。一个例子田间试验，建立异构和同构土壤网格来衡量植物种群回复<ol><li>使用土壤从复制田间土壤采集（协议1）产生一个异类治疗（ 即交替网格单元包含土壤物种或物种乙收集），并均匀处理（ 即每个网格单元包含土为1:1的混合物从物种A和B）（ 图1b）用于实验在以下步骤中的数据块1。 <ol><li>土壤消毒处理设备（镘刀，手套，塑料网格）与漂白剂的约1点10分混合物（5-10％次氯酸钠）和水以去除所有土壤颗粒。使用前干燥设备，以避免对土壤生物漂白效果。标签每件设备与实验室磁带指示重点物种的土壤它会处理，以避免交叉污染（ 如标签1抹子物种A和第二抹子物种B）和塑料格栅，以表明它是否将使用对异构或同构土壤处理。 </li><li>将可拆卸的塑料格栅进沉没入地[或其他情节或容器足够大，可以容纳电网]要充满领域的锅采集的土壤（ 如 1800厘米3 /网格单元如步骤1.1.1）。使用所需的尺寸， 例如 ，一个2×3网格的尺寸的6个细胞在步骤1.1确定的一个自定义的构造的网格（ 图1b）。 <ol><li>对于异构处理土壤交替斑块类型，土壤种类A的地方spadefuls成网格单元为α土壤和种乙土壤进入细胞内的β土（ 图1b）。 </li><li>对于均质处理，将土壤A和B交替spadefuls到每个网格单元，同时注意均匀分布两种土壤类型，避免各土壤类型的层的形成（ 图1b）。为1800厘米3的例子土壤补丁（1.1.1节），将每个土壤类型为900 立方厘米在每个网格单元。 </li><li>是SURE产生干扰等量（ 即分手土土块到相同的程度）创建异类和同类土壤处理时，为避免混淆土壤扰动土壤的异质性。 </li></ol></li><li>如果有任何空白区域仍然围绕电网的外内使用（如在图1b）的大锅里，填补了这一领域，用无菌沙子。使用任何标准的方法（ 如高压灭菌，γ-照射）消毒沙子。 </li><li>提起塑料格栅垂直出锅，留在土壤补丁完好无损。这允许来自不同个体的根在土壤中，每个工厂交互体验多个补丁，这是用于使植物的根生长成多个土壤斑块（ 即网格单元）是必不可少的。 </li><li>重复第2.1.2-2.1.4的第二对试点单位产生一个完整的实验块（ 即混合土的网格成种植每福卡l种类和均质土成植物各重点品种，共计4试点单位）的网格。 </li></ol></li><li>在实验中，其余剩下的泥土块重复步骤2.1复制集合（协议1）。块内的随机块，并重复整个实验区，利用周围如果需要，重复横向织物，以保持遮阳从外植在最低限度（未示出）。 </li><li>植物种子重点物种的进入每个实验锅（2焦点物种×2土壤处理）的每个网格单元。使用共用的种子，以避免混淆基因型植物或种子表面微生物群落与土壤处理。例如，植物种子每羊蹄属植物。放入锅中该物种（ 图1a）分别粘在塑料牙签用水溶性胶水在12种职位（每个网格单元的2个位置），以清楚地识别个体种植。 </li><li>衡量人口水库实验单位，如发芽和生存，通过个人的定期普查的ponses标志着种子的种植地点（ 例如，使用牙签如步骤2.3）。尽量减少土壤测量，以避免土壤混合斑块之间的任何响应的干扰。 <ol><li>确定基于对重点物种种群反应的预期收益率相应的普查间隔。例如，每周进行普查的鲁梅克斯属。能迅速发芽。 </li><li>继续实验的基础上，重点物种的生活史一个适当的时间。例如，继续实验至少2年短暂的常年酸模属。获得所有生命阶段的数据。 </li></ol></li></ol> 3。一个例子温室实验，在花盆异构和均质土壤衡量个人植物影响<ol><li>使用从复制田间土壤集合（协议1）土壤产生异质性处理（填充用土从一个物种或物种乙收集了锅，即各占一半）和均匀处理（ 即锅含有土壤的物种A和B的1:1混合物）（ 图2a）块1实验在下面的步骤中。 <ol><li>在运输容器（ 如桶）和灌封前，混合场采集的土壤从每个物种用无菌砂生产1:1的混合物。为此，以减轻土壤板结和改善排水盆，它是用于清洗根部特别有用，促进根系从土壤中分离。使用任何标准的方法（ 如高压灭菌，γ-照射）消毒沙子。 </li><li>一定要产生干扰等量（ 即分手土土块到相同的程度）混合每批田间土壤砂时。 </li></ol></li><li>土壤消毒处理设备（镘刀，手套，塑料片材）与AP漂白剂的近因1:10混合物（5-10％次氯酸钠）和水以去除所有土壤颗粒。使用前干燥设备，以避免对土壤生物漂白效果。标签每件设备与实验室磁带指示重点物种的土壤它会处理，以避免交叉污染（ 如标签1抹子物种A和第二抹子物种B）和硬塑料片的每一面，以指示哪些土壤类型将在异质土壤处理盆栽在它的两侧。 </li><li>创建一个使用来自两个重点物种（从第3.1.1节）的田间土壤砂混合物异构土壤处理。 <ol><li>将硬塑料片在一个锅里中心划分成两半（ 图2a）。使用锅的大小吧，这样一半是在体积等同于相应的土壤斑块大小（步骤1.1）。例如，使用一个锅一个直径为15厘米和18厘米深的土大黄属。在图1a中 （总体积为3181厘米3）。 </li><li>有两个研究人员同时从每个品种（从物种如 α土）与适当标记的镘刀加场采集的土壤锅的正确一侧，以保持双方甚至在锅里装满。 </li><li>通过垂直抬起，土壤，离开土壤斑块完好卸下塑料护栏。这使得工厂体验到土壤内锅两个补丁，用于植物必需经历的异质性。 </li><li>重复第3.3.1-3.3.3 3个额外的试点单位，以产生非均质土壤处理一个完整的块（2种×2土壤补丁中的异类治疗类型， 图2）。 </li></ol></li><li>创建一个使用来自两个重点物种（从第3.1.1节）的田间土壤砂混合物均匀土壤处理。 <ol><li>重复第3.3.1节。有两个研究人员同时添加α和β的土壤既用适当标记的镘刀，均匀地分布在每个色块内两种土壤类型和避免产生层的锅面。重复第3.3.3节。 </li><li>重复第3.4.1节的第二个试点单位，以产生均匀的土壤处理（一锅为每2个重点物种的）的一个完整的块。 </li></ol></li><li>对于剩余的块在实验中，其余土壤重复步骤3.2-3.4复制集合（协议1）。块中的随机块，地块，整个温室的长凳上。 </li></ol><img alt="图2" fo:content-width="6in" src="/files/ftp_upload/51580/51580fig2highres.jpg" width="500" /> 图2。例如温室实验设计操纵植物引起的土壤异质性。（一 ）从物种A的根影响力在该领域的区域（α土壤）和物种B（β土）采集土壤是地方D在一壶茶（异构处理）各占一半，或整个锅（均质处理）混合。 （二）物种A的植物，然后种植到实验中各土壤接插型的异构治疗和均质处理的一侧。这里，只有一个物种（A）示出植入这种设计。一个完全对等的设计将包括种植到内非均质处理各土壤处理和贴片式第二焦点物种（B）的植物。 <ol start="6"><li>重点物种A和B到每个土壤斑块类型的析因设计的植物幼苗（2种×3的土壤斑块类型[α土壤，土壤β，α和β土的均匀混合物]; 图2b）。 </li><li>测量任何单个工厂的答复表明，设备性能，如工厂规模，生物质生产，或功能特性。适当的特征来衡量取决于重点物种和科学问题兴趣。 <ol><li>继续实验，直到植物大相出现土壤斑块（ 例如约1.5倍的土壤补丁花环形成杂类草的宽度），以确保植物的根都长成这两种土壤补丁。因此，实验持续时间将取决于重点物种的生长速度。 </li><li>收获的植物和/或测量响应之前成为植物盆栽绑定，如果现实的反应，土壤环境是理想的（ 即根的生长是由锅和根圆锅底的范围限制）。例如，锅结合的植物的根系是不可能在整个以类似的方式在土壤柱觅食，在该领域的植物。 </li></ol></li></ol>

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N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Feedback+with+soil+biota+contributes+to+plant+rarity+and+invasiveness+in+communities.">Feedback with soil biota contributes to plant rarity and invasiveness in communities.</a> Nature. 417, 67-70 (2002).</li><li>Mommer, L., van Ruijven, J., Jansen, C., van de Steeg, H. M., de Kroon, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interactive+effects+of+nutrient+heterogeneity+and+competition:+implications+for+root+foraging+theory?.">Interactive effects of nutrient heterogeneity and competition: implications for root foraging theory?.</a> Funct. Ecol. 26, 66-73 (2012).</li><li>Felsenstein, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phylogenies+and+the+comparative+method.">Phylogenies and the comparative method.</a> Am. Natural. 125, 1-15 (1985).</li><li>Burns, J. H., Strauss, S. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=More+closely+related+species+are+more+ecologically+similar+in+an+experimental+test.">More closely related species are more ecologically similar in an experimental test.</a> Proc. Natl. Acad. Sci. U.S.A. 108, 5302-5307 (2011).</li><li>Fukami, T., Nakajima, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Community+assembly:+alternative+stable+states+or+alternative+transient+states.">Community assembly: alternative stable states or alternative transient states.</a> Ecol. Lett. 14, 973-984 (2011).</li></ol>

作者什么都没有透露。

植物引起的土壤异质性极有可能在自然群落的植物，因为对它们的土壤环境中的大型和经常特定物种的影响和体验，土壤（ 如彼得曼等 13）随后的植物。然而，我们这种类型的异质性对植物群落的角色的理解是最小的10,14。在这里，我们提出了操纵植物引起的土壤异质性，利用土壤不同来源（不同树种根系的影响，即区域）在该领域的方法。在协议中的关键步...

一个群落生态学的主要目标是解释和预测管辖社区组装的过程。然而，植物群落往往比预测的共存理论更多的多样化，并恢复生态学家需要了解的共存机制，成功还原多样化当地社区2。环境异质性是可以帮助解释高水平群落多样性的一个理论上的重要机制，但非均质性的实验操作是罕见3，专注于非生物异质性（ 例如，在Lundholm 4日 ）。理论，结合异质性通常假定异质性是外在的组装社区。外在的异质性是由因素，如景观类型学，它是独立的群落组成的管辖。外在的异质性可以通过生态位分化（里维会导致共处星期三在墨尔本等。3，如帕卡拉和蒂尔曼5和切森6）。然而，还有许多相关的植物群落对环境的异质性可能是内在的社会，发展成为社会各界及组装根据物种在社会上的身份。内在的异质性可导致生物反馈，可通过负的频率依赖性（ 如贝沃等。7）导致共存。在这里，我们描述了操纵植物引起的土壤异质性，一个类型的土壤异质性是固有的社会和来自植物 - 土壤反馈的新方法。 植物-土壤反馈（PSF）发生时，植物影响土壤结构，化学，生物或在影响着土壤后续工厂绩效的方式，和PSF对原生植物群落8工厂性能大的平均效应。涤纶短纤的研究通常是收集来自现场的土壤或土壤条件实验，然后问植物在土壤中相对同种的表现如何，以异种或灭菌土9。如果植物在土壤相对同种更好的表现来引用的土壤，然后PSF是积极的，而如果植物在土壤中引用有更好的表现，PSF是否定的。友情负PSF可以导致物种7之间的频率依赖性并存。而PSF的平均效果是充分表征8，空间异质性在PSF的影响知之甚少10。 由于PSF发生在个别工厂7的规模和因为植物往往是非随机分布在空间和时间，涤纶短纤有可能导致土壤异质性，我们称之为植物引起的土壤异质性 。不像许多其他形式的异质性（ 如风景的拓扑结构），这heterogeneity是固有的装配社区，从而可能影响社会装配不同于异质性更外在形式。为了了解这种形式的异质性对植物的性能和共存的影响，我们需要操纵植物引起的土壤异质性的实验方法。在这里，我们展示了这样一种方法，即用土壤的两个物种空调创建具有两个土起源和均质处理，这是两个土起源的混合物单独的补丁异构处理。这种土壤混合可以代表在现场至少有两个可能的情况下:（1）干扰（ 如啮齿类动物，农业），其中混合不同来源的土壤或两种接近的成长（2）植物，使得根系影响其区域交融，均质。 我们目前使用的植物引起的土壤异质性在不同LEVE回答关键问题的两个示例实验生态组织的LS:（1）不要植物种群应对种植引起的土壤异质性？及（2）不要单独植物植物引起的土壤异质性反应？我们描述了现场实验用6土壤补丁使用2土壤补丁来解决第二个问题，解决的第一个问题和一个温室试验。量化人口和个别植物对土壤异质性是必不可少的理解异质性影响的社区如何组装。

<table><tbody><tr><td>Shovel(s)</td><td>Any</td><td>NA</td><td>It is helpful to have at least two shovels, one for each species of soil origin.</td></tr><tr><td>Trowel(s)</td><td>Any</td><td>NA</td><td>It is necessary to have at least two trowels of identical size, one for each species of soil origin.</td></tr><tr><td>Gloves</td><td>Any</td><td>NA</td><td>Gardening gloves can be used.</td></tr><tr><td>Diluted bleach</td><td>Any</td><td>NA</td><td>We use an ~1:10 concentration of household bleach (containing 5-10% NaClO) to water to sterilize all equipment between soil collections.</td></tr><tr><td>Plastic grid(s)</td><td>Any</td><td>NA</td><td>CUSTOM. We used plastic sheeting from the construction of greenhouse walls to create the grid used in the field experiment. However any stiff plastic that can be manipulated can be used. It is helpful to have three grids to produce reciprocal heterogeneous treatments and a homogeneous treatment without needing to sterilize between each experimental unit.</td></tr><tr><td>Plastic dividers</td><td>Any</td><td>NA</td><td>CUSTOM. We used stiff sheets of plastic, cut to fit the pot minimum width, such that they can slide down to the bottom of the pot for the greenhouse experiment. It is helpful to have at least two dividers, one for heterogeneous and one for homogeneous treatments, if investigators want to randomize the order in which experimental units within a block are filled without needing to sterilize the divider in between each experimental unit.</td></tr><tr><td>Buckets or wheelbarrows</td><td>Any</td><td>NA</td><td>Any container for transporting soils.</td></tr><tr><td>Seeds</td><td>Any</td><td>NA</td><td>We collect seeds in the field by hand. Seeds can also be ordered from horticultural suppliers, if appropriate.</td></tr><tr><td>Plastic toothpicks</td><td>Soodhalter Plastics, Inc.</td><td>805KP</td><td>We plant individual seeds glued on toothpick in the field experiment to facilitate monitoring germination and survival of individuals.</td></tr><tr><td>Water soluble glue</td><td>Elmer&#039;s</td><td>Elmer&#039;s Glue-all</td><td>Any water soluble glue can be used to adhere seeds to plastic toothpicks.</td></tr><tr><td>Pots</td><td>Any</td><td>NA</td><td>Pot size will depend on experimental plants used and number of soil patches desired (&lt;em&gt;e.g.&lt;/em&gt; 2 or 6).</td></tr><tr><td>Sand</td><td>Any</td><td>NA</td><td>Coarse sand may be mixed with field soils to improve drainage in pots.</td></tr><tr><td>Lab tape&amp;nbsp;</td><td>Any</td><td>NA</td><td>Tape may be used to label equipment used in handling soils with the species of origin.</td></tr><tr><td>Pin flags</td><td>Any</td><td>NA</td><td>Flags can be used to identify individuals in the field prior to soil collection.</td></tr><tr><td>Landscape fabric</td><td>Any</td><td>NA</td><td>Landscape fabric can be used in the field to minimize the growth of plants outside experimental plots.</td></tr></tbody></table>

experimental protocol for manipulating plant-induced soil heterogeneity

共存理论常常被环境异质性作为独立的群落组成的，但生物反馈，如植物 - 土壤反馈（PSF）对植物的性能有很大的影响，并创造环境异质性依赖于群落组成。理解的PSF对植物群落组件的重要性就必须异质性的PSF的作用，除了意味着PSF作用的理解。在这里，我们描述了一个协议，用于操纵植物引起的土壤异质性。两个实验的例子给出:（1）现场实验用6片栅格的土壤测量植物种群的反应和（2）的温室实验2补丁土壤测量单株反应。土壤可以从根影响（从根圈土壤和直接相邻的根际）领域植物从同种和异种的植物物种的区被收集。复制收集离子被用来避免pseudoreplicating土壤样品。这些土壤，然后放入异构治疗或混合的均匀化处理单独的补丁。应注意，以确保异质和同质化的治疗体会土壤扰动程度相同。植物可以被放置在这些土壤处理，以确定植物引起的土壤异质性对设备性能的影响。我们证明了植物诱导异质性的结果，也许是因为这些反馈的动态性质不同的结果比预测由传统的共存模式。理论，结合环境异质性的装配社区和额外的实证工作的影响是必要的，以确定何时异质性内在的组装社会将导致与外在的异质性对群落组成比较不同的装配结果。

种反应以种植引起的土壤异质性不同的方式在人口和个体水平（ 图3和图4），与社区组装的影响。要确定植物种群是否对植物引起的土壤异质性反应，现场试验，采用三对同类物种的确立为协议2。植物种群censused每周三个月，并种植种子发芽和那些苗的总比例，在第一个生长季死亡（其中死亡率表示的生存的倒数）进行计算（ 图3）的总比例。我们发现有显?...

Watch this Scientific Journal Video about Experimental Protocol for Manipulating Plant-induced Soil Heterogeneity at JoVE.com

操纵植物引起的土壤异质性的实验方案|环境 |视频

Experimental Protocol for Manipulating Plant-induced Soil Heterogeneity

理解物种共存的环境异质性的作用通常专注于各类异质性是外在的社会的物种组成。我们提供新的详细的方法使用土壤受植物 - 土壤反馈调节，或异质性固有的群落组成产生土壤异质性的治疗方法。

用于操纵植物诱导土壤异质性的实验协议

Coexistence theory has often treated environmental heterogeneity as being independent of the community composition; however biotic feedbacks such as ...

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18.6K 次观看.  Case Western Reserve University. 理解物种共存的环境异质性的作用通常专注于各类异质性是外在的社会的物种组成。我们提供新的详细的方法使用土壤受植物 - 土壤反馈调节，或异质性固有的群落组成产生土壤异质性的治疗方法。 

视频: Experimental Protocol for Manipulating Plant-induced Soil Heterogeneity

A Protocol for Conducting Rainfall Simulation to Study Soil Runoff

Rainfall is a driving force for the transport of environmental contaminants from agricultural soils to surficial water bodies via surface runoff. The objective of this study was to characterize the effects of antecedent soil moisture content on the fate and transport of surface applied commercial urea, a common form of nitrogen (N) fertilizer, following a rainfall event that occurs within 24&#160;hr&#160;after fertilizer application. Although urea is assumed to be readily hydrolyzed to ammonium and therefore not often available for transport, recent studies suggest that urea can be transported from agricultural soils to coastal waters where it is implicated in harmful algal blooms. A rainfall simulator was used to apply a consistent rate of uniform rainfall across packed soil boxes that had been prewetted to different soil moisture contents. By controlling rainfall and soil physical characteristics, the effects of antecedent soil moisture on urea loss were isolated. Wetter soils exhibited shorter time from rainfall initiation to runoff initiation, greater total volume of runoff, higher urea concentrations in runoff, and greater mass loadings of urea in runoff. These results also demonstrate the importance of controlling for antecedent soil moisture content in studies designed to isolate other variables, such as soil physical or chemical characteristics, slope, soil cover, management, or rainfall characteristics. Because rainfall simulators are designed to deliver raindrops of similar size and velocity as natural rainfall, studies conducted under a standardized protocol can yield valuable data that, in turn, can be used to develop models for predicting the fate and transport of pollutants in runoff.

A rainfall simulator was used to apply a consistent rate of uniform rainfall to packed soil boxes in a study of the fate and transport of urea, a nonpoint source environmental contaminant. Under uniform soil and rainfall conditions, antecedent soil moisture content exerted strong control over urea loss in surface runoff.

一个协议，用于开展降雨模拟研究土壤径流

Rainfall is a driving force for the transport of environmental contaminants from agricultural soils to surficial water bodies via surface runoff. The ...

科研

环境科学

Soil Lysimeter Excavation for Coupled Hydrological, Geochemical, and Microbiological Investigations

Studying co-evolution of hydrological and biogeochemical processes in the subsurface of natural landscapes can enhance the understanding of coupled Earth-system processes. Such knowledge is imperative in improving predictions of hydro-biogeochemical cycles, especially under climate change scenarios. We present an experimental method, designed to capture sub-surface heterogeneity of an initially homogeneous soil system. This method is based on destructive sampling of a soil lysimeter designed to simulate a small-scale hillslope. A weighing lysimeter of one cubic meter capacity was divided into sections (voxels) and was excavated layer-by-layer, with sub samples being collected from each voxel. The excavation procedure was aimed at detecting the incipient heterogeneity of the system by focusing on the spatial assessment of hydrological, geochemical, and microbiological properties of the soil. Representative results of a few physicochemical variables tested show the development of heterogeneity. Additional work to test interactions between hydrological, geochemical, and microbiological signatures is planned to interpret the observed patterns. Our study also demonstrates the possibility of carrying out similar excavations in order to observe and quantify different aspects of soil-development under varying environmental conditions and scale.

This study presents an excavation method for investigating subsurface hydrological, geochemical, and microbiological heterogeneity of a soil lysimeter. The lysimeter simulates an artificial hillslope which was initially under homogeneous condition and had been subjected to approximately 5,000 mm of water over eight cycles of irrigation in an 18-month period.

土壤蒸渗仪开挖加之水文，地球化学和微生物调查

Studying co-evolution of hydrological and biogeochemical processes in the subsurface of natural landscapes can enhance the understanding of coupled ...

Isolation and Analysis of Microbial Communities in Soil, Rhizosphere, and Roots in Perennial Grass Experiments

Plant and soil microbiome studies are becoming increasingly important for understanding the roles microorganisms play in agricultural productivity. The purpose of this manuscript is to provide detail on how to rapidly sample soil, rhizosphere, and endosphere of replicated field trials and analyze changes that may occur in the microbial communities due to sample type, treatment, and plant genotype. The experiment used to demonstrate these methods consists of replicated field plots containing two, pure, warm-season grasses (Panicum virgatum and Andropogon gerardii) and a low-diversity grass mixture (A. gerardii, Sorghastrum nutans, and Bouteloua curtipendula). Briefly, plants are excavated, a variety of roots are cut and placed in phosphate buffer, and then shaken to collect the rhizosphere. Roots are brought to the laboratory on ice and surface sterilized with bleach and ethanol (EtOH). The rhizosphere is filtered and concentrated by centrifugation. Excavated soil from around the root ball is placed into plastic bags and brought to the lab where a small amount of soil is taken for DNA extractions. DNA is extracted from roots, soil, and rhizosphere and then amplified with primers for the V4 region of the 16S rRNA gene. Amplicons are sequenced, then analyzed with open access bioinformatics tools. These methods allow researchers to test how the microbial community diversity and composition varies due to sample type, treatment, and plant genotype. Using these methods along with statistical models, the representative results demonstrate there are significant differences in microbial communities of roots, rhizosphere, and soil. Methods presented here provide a complete set of steps for how to collect field samples, isolate, extract, quantify, amplify, and sequence DNA, and analyze microbial community diversity and composition in replicated field trials.

Excavation of plant roots from the field as well as processing of samples into endosphere, rhizosphere, and soil are described in detail, including DNA extraction and data analysis methods. This paper is designed to enable other laboratories to use these techniques for the study of soil, endosphere, and rhizosphere microbiomes.

多年生草试验中土壤、根际和根系微生物群落的分离与分析

Plant and soil microbiome studies are becoming increasingly important for understanding the roles microorganisms play in agricultural productivity. The ...

Sampling Soils in a Heterogeneous Research Plot

Soils are highly heterogeneous. In general, the number of soil samples required for soil research has always been determined arbitrarily and the associated accuracy is unknown. Here, we present a detailed protocol for efficient and clustered soil sampling in a research plot and, relying on a pilot sampling using this design, for demonstrating soil spatial heterogeneity and informing reasonable sample sizes and associated accuracy for future study. The protocol mainly comprises four steps: sampling design, field collection, soil analysis, and geostatistical analysis. The step-by-step procedure is modified according to former publications. Two examples will be presented to demonstrate contrasting spatial distributions of soil organic carbon (SOC) and soil microbial biomass carbon (MBC) under different management practices. In addition, we present a strategy to determine the sample size requirement (SSR) given a certain level of accuracy based on the plot-level coefficient of variation (CV). The field sampling protocol and the quantitative determination of the sample size will assist researchers in seeking feasible sampling strategies to meet research needs and resources' availability.

The traditional soil-sampling procedure determines the number of soil samples arbitrarily. Here, we provide a simple yet efficient clustered soil-sampling design to demonstrate soil spatial heterogeneity and quantitatively determine the number of soil samples required and the associated sampling accuracy.

在异构研究图中取样土壤

Soils are highly heterogeneous. In general, the number of soil samples required for soil research has always been determined arbitrarily and the ...

Investigation of Plant Interactions Across Common Mycorrhizal Networks Using Rotated Cores

Arbuscular mycorrhizal (AM) fungi influence plant mineral nutrient uptake and growth, hence, they have the potential to influence plant interactions. The power of their influence is in extraradical mycelia that spread beyond nutrient depletion zones found near roots to ultimately interconnect individuals within a common mycorrhizal network (CMN). Most experiments, however, have investigated the role of AM fungi in plant interactions by growing plants with versus without mycorrhizal fungi, a method that fails to explicitly address the role of CMNs. Here, we propose a method that manipulates CMNs to investigate their role in plant interactions. Our method uses modified containers with conical bottoms with a nylon mesh and/or hydrophobic material covering slotted openings, 15N fertilizer, and a nutrient-poor interstitial sand. CMNs are left either intact between interacting individuals, severed by rotation of containers, or prevented from forming by a solid barrier. Our findings suggest that rotating containers is sufficient to disrupt CMNs and prevent their effects on plant interactions across CMNs. Our approach is advantageous because it mimics aspects of nature, such as seedlings tapping into already established CMNs and the use of a suite of AM fungi that may provide diverse benefits. Although our experiment is limited to investigating plants at the seedling stage, plant interactions across CMNs can be detected using our approach which therefore can be applied to investigate biological questions about the functioning of CMNs in ecosystems.

Most plants within communities likely are interconnected by arbuscular mycorrhizal (AM) fungi, but mediation of plant interactions by them has been investigated primarily by growing plants with versus without mycorrhizas. We present a method to manipulate common mycorrhizal networks among mycorrhizal plants to investigate their consequences for plant interactions.

旋转芯在常见菌根网络中植物相互作用的研究

Arbuscular mycorrhizal (AM) fungi influence plant mineral nutrient uptake and growth, hence, they have the potential to influence plant interactions. The ...

A Telemetric, Gravimetric Platform for Real-Time Physiological Phenotyping of Plant&ndash;Environment Interactions

Food security for the growing global population is a major concern. The data provided by genomic tools far exceeds the supply of phenotypic data, creating a knowledge gap. To meet the challenge of improving crops to feed the growing global population, this gap must be bridged.
Physiological traits are considered key functional traits in the context of responsiveness or sensitivity to environmental conditions. Many recently introduced high-throughput (HTP) phenotyping techniques are based on remote sensing or imaging and are capable of directly measuring morphological traits, but measure physiological parameters mainly indirectly.
This paper describes a method for direct physiological phenotyping that has several advantages for the functional phenotyping of plant&#8211;environment interactions. It helps users overcome the many challenges encountered in the use of load-cell gravimetric systems and pot experiments. The suggested techniques will enable users to distinguish between soil weight, plant weight and soil water content, providing a method for the continuous and simultaneous measurement of dynamic soil, plant and atmosphere conditions, alongside the measurement of key physiological traits. This method allows researchers to closely mimic field stress scenarios while taking into consideration the environment&#8217;s effects on the plants&#8217; physiology. This method also minimizes pot effects, which are one of the major problems in pre-field phenotyping. It includes a feed-back fertigation system that enables a truly randomized experimental design at a field-like plant density. This system detects the soil-water-content limiting threshold (&#952;) and allows for the translation of data into knowledge through the use of a real-time analytic tool and an online statistical resource. This method for the rapid and direct measurement of the physiological responses of multiple plants to a dynamic environment has great potential for use in screening for beneficial traits associated with responses to abiotic stress, in the context of pre-field breeding and crop improvement.

A Telemetric, Gravimetric Platform for Real-Time Physiological Phenotyping of Plant&#8211;Environment Interactions

This high-throughput, telemetric, whole-plant water relations gravimetric phenotyping method enables direct and simultaneous real-time measurements, as well as the analysis of multiple yield-related physiological traits involved in dynamic plant&#8211;environment interactions.

植物与环境相互作用实时生理表型的遥测重力平台

Food security for the growing global population is a major concern. The data provided by genomic tools far exceeds the supply of phenotypic data, creating ...

Inoculation Strategies to Infect Plant Roots with Soil-Borne Microorganisms

The rhizosphere harbors a highly complex microbial community in which plant roots are constantly challenged. Roots are in close contact with a wide variety of microorganisms, but studies on soil-borne interactions are still behind those performed on aboveground organs. Although some inoculation strategies for infecting model plants with model root pathogens are described in the literature, it remains difficult to get a comprehensive methodological overview. To address this problem, three different root inoculation systems are precisely described that can be applied to gain insights into the biology of root-microbe interactions. For illustration, Verticillium species (namely, V. longisporum and V. dahliae) were employed as root invading model pathogens. However, the methods can be easily adapted to other root colonizing microbes - both pathogenic and beneficial. By colonizing the plant xylem, vascular soil-borne fungi such as Verticillium spp. exhibit a unique lifestyle. After root invasion, they spread via the xylem vessels acropetally, reach the shoot, and elicit disease symptoms. Three representative plant species were chosen as model hosts: Arabidopsis thaliana, economically important oilseed rape (Brassica napus), and tomato (Solanum lycopersicum). Step-by-step protocols are given. Representative results of pathogenicity assays, transcriptional analyses of marker genes, and independent confirmations by reporter constructs are shown. Furthermore, the advantages and disadvantages of each inoculation system are thoroughly discussed. These proven protocols can assist in providing approaches for research questions on root-microbe interactions. Knowing how plants cope with microbes in the soil is crucial for developing new strategies to improve agriculture.

This protocol presents a detailed summary of strategies to inoculate plant roots with soil-borne microbes. Exemplified for the fungi Verticillium longisporum and Verticillium dahliae, three different root infection systems are described. Potential applications and possible downstream analyses are highlighted, and advantages or disadvantages are discussed for each system.

用土壤微生物感染植物根系的接种策略

The rhizosphere harbors a highly complex microbial community in which plant roots are constantly challenged. Roots are in close contact with a wide ...

Simulating Temperature in a Soil Incubation Experiment

The study of warming impact on soils requires a realistic and accurate representation of temperature. In laboratory incubation studies, a widely adopted method has been to render constant temperatures in multiple chambers, and via comparisons of soil responses between low- and high-temperature chambers, to derive the warming impact on soil changes. However, this commonly used method failed to imitate both the magnitude and amplitude of actual temperatures as observed in field conditions, thus potentially undermining the validity of such studies. With sophisticated environmental chambers becoming increasingly available, it is imperative to examine alternative methods of temperature control for soil incubation research. This protocol will introduce a state-of-the-art environmental chamber and demonstrate both conventional and new methods of temperature control to improve the experimental design of soil incubation. The protocol mainly comprises four steps: temperature monitoring and programming, soil collection, laboratory incubation, and warming effect comparison. One example will be presented to demonstrate different methods of temperature control and the resultant contrasting warming scenarios; that is, a constant temperature design referred to as stepwise warming (SW) and simulated in situ temperature design as gradual warming (GW), as well as their effects on soil respiration, microbial biomass, and extracellular enzyme activities. In addition, we present a strategy to diversify temperature change scenarios to meet specific climate change research needs (e.g., extreme heat). The temperature control protocol and the recommended well-tailored and diversified temperature change scenarios will assist researchers in establishing reliable and realistic soil incubation experiments in the laboratory.

Laboratory soil warming experiments usually employ two or more constant temperatures in multiple chambers. By presenting a sophisticated environmental chamber, we provide an accurate temperature control method to imitate the magnitude and amplitude of in situ soil temperature and improve the experimental design of soil incubation studies.

模拟土壤孵育实验中的温度

The study of warming impact on soils requires a realistic and accurate representation of temperature. In laboratory incubation studies, a widely adopted ...

JenaTron - An Experimental Approach to Study the Effects of Plant History and Soil History on Grassland Ecosystem Functioning

The global loss of biodiversity has motivated many studies that experimentally vary plant species richness and examine the consequences for ecosystem functioning. Such experiments generally show a positive relationship between above- and below-ground biodiversity and the functioning of terrestrial ecosystems. Moreover, this relationship tends to strengthen over time, seen as enhanced functioning of diverse plant communities and reduced functioning of low-diversity plant communities. Differences in multitrophic community assembly and biotic interactions in high- versus low-diversity plant communities are hypothesized to affect plant performance by altering consumer community structure and function and driving plastic or micro-evolutionary responses of plant species in the plant communities. To resolve this complex interplay of community history, we separated these effects into plant and soil history. Plant history refers to all plant-level responses to past abiotic and biotic selection pressures experienced in their communities, while soil history relates to all abiotic and biotic soil properties developed as a legacy of plant-soil interactions under variable plant diversity. We set up a biodiversity experiment in an Ecotron, a terrestrial mesocosm facility that allows controlling environmental conditions above- and below-ground, to test whether the strengthening biodiversity-ecosystem functioning relationship is due to soil history, plant history, or a combination of both. We established a plant diversity gradient consisting of 1, 2, 3, and 6 grassland plant species and factorially nested with soil history and plant history treatments for each level of plant species richness. Representative results demonstrate the successful establishment of target treatments in the Ecotron experiment, observing the effects of plant and soil history on initial plant development and final plant growth. Additionally, we provide a case study for data analysis of individual response variables. We outline research objectives and methods to comprehensively assess the multifunctional responses to the experimental treatments necessary to ultimately address the overarching hypothesis.

Here we present a study established in the iDiv Ecotron, terrestrial mesocosm chambers with controlled environmental conditions above- and below-ground, to study the independent and interactive effects of plant history and soil history on ecosystem functioning of grassland communities along a plant diversity gradient.

JenaTron - 一种研究植物历史和土壤历史对草原生态系统功能影响的实验方法

The global loss of biodiversity has motivated many studies that experimentally vary plant species richness and examine the consequences for ecosystem ...

增强 CO2 封存：促进矿物风化的土壤生物群方法

Design and Construction of an Experimental Setup to Enhance Mineral Weathering through the Activity of Soil Organisms

Enhanced weathering (EW) is an emerging carbon dioxide (CO2) removal technology that can contribute to climate change mitigation. This technology relies on accelerating the natural process of mineral weathering in soils by manipulating the abiotic variables that govern this process, in particular mineral grain size and exposure to acids dissolved in water. EW mainly aims at reducing atmospheric CO2 concentrations by enhancing inorganic carbon sequestration. Until now, knowledge of EW has been mainly gained through experiments that focused on the abiotic variables known for stimulating mineral weathering, thereby neglecting the potential influence of biotic components. While bacteria, fungi, and earthworms are known to increase mineral weathering rates, the use of soil organisms in the context of EW remains underexplored. 
 This protocol describes the design and construction of an experimental setup developed to enhance mineral weathering rates through soil organisms while concurrently controlling abiotic conditions. The setup is designed to maximize weathering rates while maintaining soil organisms' activity. It consists of a large number of columns filled with rock powder and organic material, located in a climate chamber and with water applied via a downflow irrigation system. Columns are placed above a fridge containing jerrycans to collect the leachate. Representative results demonstrate that this setup is suitable to ensure the activity of soil organisms and quantify their effect on inorganic carbon sequestration. Challenges remain in minimizing leachate losses, ensuring homogeneous ventilation through the climate chamber, and avoiding flooding of the columns. With this setup, an innovative and promising approach is proposed to enhance mineral weathering rates through the activity of soil biota and disentangle the effect of biotic and abiotic factors as drivers of EW.

作者聚焦：揭示蚯蚓在增强矿物风化作用以去除 CO2 中的作用 

Here we present the construction and operation of an experimental setup to enhance mineral weathering through the activity of soil organisms while concurrently manipulating abiotic variables known to stimulate weathering. Representative results from the functioning of the setup and sample analyses are discussed together with points for improvement.

设计和建造实验装置，通过土壤生物的活动增强矿物风化

Enhanced weathering (EW) is an emerging carbon dioxide (CO2) removal technology that can contribute to climate change mitigation. This technology relies ...