Name: microplot design and plant and soil sample preparation for 15nitrogen analysis
Uploaded: 2020-05-10T14:00:00
Description: Watch this Scientific Journal Video about Microplot Design and Plant and Soil Sample Preparation for 15Nitrogen Analysis at JoVE.com

作者感谢明尼苏达州玉米研究与促进委员会、休格-哈里森研究金和明尼苏达州发现、研究和无病毒经济 （MnDRIVE） 研究金的支持。

1. 现场现场描述
注：在进行15N示踪场试验时，选定地点应尽量减少因土壤、地形和物理特征而变化5。由于坡度、风或水迁移或耕种，横向土壤移动后可能发生交叉污染，而土壤N的垂直分布可能受到地下水流和瓦片排水的影响。
<ol><li>描述实验场址，包括过去的管理（如以前的作物和耕种）、经纬度、土壤物理和化学性质（例如?...

<ol>
	<li>Sharp, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Principles of Stable Isotope Geochemistry. , (2017).</li><li>Van Cleemput, O., Zapata, F., Vanlauwe, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Guidelines+on+Nitrogen+Management+in+Agricultural+Systems.">Guidelines on Nitrogen Management in Agricultural Systems.</a> Guidelines on Nitrogen Management in Agricultural Systems. 29 (29), 19 (2008).</li><li>Hauck, R. D., Meisinger, J. J., Mulvaney, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Practical+considerations+in+the+use+of+nitrogen+tracers+in+agricultural+and+environmental+research.">Practical considerations in the use of nitrogen tracers in agricultural and environmental research.</a> Methods of Soil Analysis: Part 2-Microbiological and Biochemical Properties. , 907-950 (1994).</li><li>Bedard-Haughn, A., Van Groenigen, J. W., Van Kessel, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tracing+15N+through+landscapes:+Potential+uses+and+precautions.">Tracing 15N through landscapes: Potential uses and precautions.</a> Journal of Hydrology. 272 (1-4), 175-190 (2003).</li><li>Peterson, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Agricultural Field Experiments: Design and Analysis. , (1994).</li><li>Follett, R. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Innovative+15N+microplot+research+techniques+to+study+nitrogen+use+efficiency+under+different+ecosystems.">Innovative 15N microplot research techniques to study nitrogen use efficiency under different ecosystems.</a> Communications in Soil Science and Plant Analysis. 32 (7/8), 951-979 (2001).</li><li>Russelle, M. P., Deibert, E. J., Hauck, R. D., Stevanovic, M., Olson, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+water+and+nitrogen+management+on+yield+and+15N-depleted+fertilizer+use+efficiency+of+irrigated+corn.">Effects of water and nitrogen management on yield and 15N-depleted fertilizer use efficiency of irrigated corn.</a> Soil Science Society of America Journal. 45 (3), 553-558 (1981).</li><li>Schindler, F. V., Knighton, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fate+of+Fertilizer+Nitrogen+Applied+to+Corn+as+Estimated+by+the+Isotopic+and+Difference+Methods.">Fate of Fertilizer Nitrogen Applied to Corn as Estimated by the Isotopic and Difference Methods.</a> Soil Science Society of America Journal. 63, 1734 (1999).</li><li>Stevens, W. B., Hoeft, R. G., Mulvaney, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fate+of+Nitrogen-15+in+a+Long-Term+Nitrogen+Rate+Study.">Fate of Nitrogen-15 in a Long-Term Nitrogen Rate Study.</a> Agronomy Journal. 97 (4), 1037 (2005).</li><li>Recous, S., Fresneau, C., Faurie, G., Mary, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+fate+of+labelled+15N+urea+and+ammonium+nitrate+applied+to+a+winter+wheat+crop.">The fate of labelled 15N urea and ammonium nitrate applied to a winter wheat crop.</a> Plant and Soil. 112 (2), 205-214 (1988).</li><li>Abendroth, L. J., Elmore, R. W., Boyer, M. J., Marlay, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Corn Growth and Development. , (2011).</li><li>Gomez, K. A., Gomez, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Statistical Procedures for Agricultural Research. , (1984).</li><li>Khan, S. A., Mulvaney, R. L., Brooks, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diffusion+Methods+for+Automated+Nitrogen-15+Analysis+using+Acidified+Disks.">Diffusion Methods for Automated Nitrogen-15 Analysis using Acidified Disks.</a> Soil Science Society of America Journal. 62 (2), 406 (1998).</li><li>Horneck, D. A., Miller, R. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+Total+Nitrogen+in+Plant+Tissue.">Determination of Total Nitrogen in Plant Tissue.</a> Handbook of Reference Methods for Plant Analysis. , 75-84 (1998).</li><li>. Carbon (13C) and Nitrogen (15N) Analysis of Solids by EA-IRMS Available from: <a target="_blank" href="https://stableisotopefacility.ucdavis.edu/13cand15n.html">https://stableisotopefacility.ucdavis.edu/13cand15n.html</a> (2019)</li><li>Stevens, W. B., Hoeft, R. G., Mulvaney, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fate+of+Nitrogen-15+in+a+Long-Term+Nitrogen+Rate+Study:+II.+Nitrogen+Uptake+Efficiency.">Fate of Nitrogen-15 in a Long-Term Nitrogen Rate Study: II. Nitrogen Uptake Efficiency.</a> Agronomy Journal. 97 (4), 1046 (2005).</li><li>. Fertilizing Corn in Minnesota Available from: <a target="_blank" href="https://extension.umn.edu/crop-specific-needs/fertilizing-corn-minnesota">https://extension.umn.edu/crop-specific-needs/fertilizing-corn-minnesota</a> (2018)</li><li>Blake, G. R., Hartge, K. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bulk+Density.">Bulk Density.</a> Methods of Soil Analysis: Part 1 Physical and Mineralogical Methods. , 363-375 (1986).</li><li>Jokela, W. E., Randall, G. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fate+of+Fertilizer+Nitrogen+as+Affected+by+Time+and+Rate+of+Application+on+Corn.">Fate of Fertilizer Nitrogen as Affected by Time and Rate of Application on Corn.</a> Soil Science Society of America Journal. 61 (6), 1695 (2010).</li><li>Hart, S. C., Stark, J. M., Davidson, E. A., Firestone, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nitrogen+Mineralization,+Immobilization,+and+Nitrification.">Nitrogen Mineralization, Immobilization, and Nitrification.</a> Methods of Soil Analysis, Part 2. Microbiological and Biochemical Properties. (5), 985-1018 (1994).</li><li>Olson, R. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fate+of+tagged+nitrogen+fertilizer+applied+to+irrigated+corn.">Fate of tagged nitrogen fertilizer applied to irrigated corn.</a> Soil Science Society of America Journal. 44 (3), 514-517 (1980).</li><li>Follett, R. F., Porter, L. K., Halvorson, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Border+Effects+on+Nitrogen-15+Fertilized+Winter+Wheat+Microplots+Grown+in+the+Great+Plains.">Border Effects on Nitrogen-15 Fertilized Winter Wheat Microplots Grown in the Great Plains.</a> Agronomy Journal. 83 (3), 608-612 (1991).</li><li>Balabane, M., Balesdent, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Input+of+fertilizer-derived+labelled+n+to+soil+organic+matter+during+a+growing+season+of+maize+in+the+field.">Input of fertilizer-derived labelled n to soil organic matter during a growing season of maize in the field.</a> Soil Biology and Biochemistry. 24 (2), 89-96 (1992).</li><li>Recous, S., Machet, J. M., Mary, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+partitioning+of+fertilizer-N+between+soil+and+crop:+Comparison+of+ammonium+and+nitrate+applications.">The partitioning of fertilizer-N between soil and crop: Comparison of ammonium and nitrate applications.</a> Plant and Soil. 144 (1), 101-111 (1992).</li><li>Bigeriego, M., Hauck, R. D., Olson, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Uptake,+Translocation+and+Utilization+of+15N-Depleted+Fertilizer+in+Irrigated+Corn.">Uptake, Translocation and Utilization of 15N-Depleted Fertilizer in Irrigated Corn.</a> Soil Science Society of America Journal. 43 (3), 528 (1979).</li><li>Glendining, M. J., Poulton, P. R., Powlson, D. S., Jenkinson, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fate+of15N-labelled+fertilizer+applied+to+spring+barley+grown+on+soils+of+contrasting+nutrient+status.">Fate of15N-labelled fertilizer applied to spring barley grown on soils of contrasting nutrient status.</a> Plant and Soil. 195 (1), 83-98 (1997).</li><li>Khanif, Y. M., Cleemput, O., Baert, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Field+study+of+the+fate+of+labelled+fertilizer+nitrate+applied+to+barley+and+maize+in+sandy+soils.">Field study of the fate of labelled fertilizer nitrate applied to barley and maize in sandy soils.</a> Fertilizer Research. 5 (3), 289-294 (1984).</li></ol>

稳定的同位素研究是通过土壤作物系统跟踪和量化FDN的有用工具。然而，有三个主要假设与N示踪器研究有关，如果违反，可能会使使用这种方法得出的结论无效。它们是 1） 示踪剂在整个系统中均匀分布，2） 研究下的进程以相同的速率发生，3） N 离开15N 富集池不返回3。由于本研究对整个土壤作物系统中FDN总量分布感兴趣，假设2和假设3是关注最少的21。<...

化肥氮（N）的使用对于满足全球不断增长的人口的粮食、纤维、饲料和燃料需求至关重要，但农业领域的氮气损失可能会对环境质量产生负面影响。由于N在土壤作物系统中经历了许多转变，因此，要改进提高N使用效率并最大限度地减少环境损失的管理方法，必须更好地了解N循环、作物利用率和肥料N的总体命运。传统的 N 肥料研究主要侧重于处理对季末测量的影响，如作物产量、作物 N 吸收相对于 N 速率（明显的肥料使用效率）和残留土壤 N。虽然这些研究量化了整个系统N投入、产出和效率，但它们无法识别或量化土壤作物系统中来自肥料来源或土壤的N。必须使用使用稳定同位素的不同方法来跟踪和量化土壤作物系统中衍生的N（FDN）肥料的命运。
氮有两种稳定的同位素，14N和15N，在自然界中相对恒定比为272：1，为14N/15N151（浓度为0.366原子% 15N或3600 ppm 15N2，3）。增加15N富肥增加了土壤系统15N含量。由于15N富肥与未富土N混合，14N/15N比率的测量变化15使研究人员能够跟踪FDN在土壤轮廓和作物,3，4。质量平衡可以通过测量系统中15N 示踪器的总量及其每个部件2来计算。由于15种N富肥比传统肥料贵得多，15个N富肥通常嵌入到处理地块中。本文的目的是描述利用微图对玉米（Zea mays L.）的多个季节土壤和植物取样事件进行小图研究设计，并提出为总共15个N分析准备植物和土壤样本的协议。然后，这些结果可用于估算 N 肥料的使用效率，并在散装土壤和作物中为 FDN 创建部分 N 预算核算。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>20 mL scintillation vial</td>
			<td>ANY; Fisher Scientific is one example</td>
			<td>0334172C</td>
			<td></td>
		</tr>
		<tr>
			<td>250 mL borosilicate glass bottle</td>
			<td>QORPAK</td>
			<td>264047</td>
			<td></td>
		</tr>
		<tr>
			<td>48-well plate</td>
			<td>EA Consumables</td>
			<td>E2063</td>
			<td></td>
		</tr>
		<tr>
			<td>96-well plate</td>
			<td>EA Consumables</td>
			<td>E2079</td>
			<td></td>
		</tr>
		<tr>
			<td>Cloth parts bag (30x50 cm)</td>
			<td>ANY</td>
			<td>NA</td>
			<td>For corn ears</td>
		</tr>
		<tr>
			<td>CO2 Backpack Sprayer</td>
			<td>ANY; Bellspray Inc is one example</td>
			<td>Model T</td>
			<td></td>
		</tr>
		<tr>
			<td>Coin envelop (6.4x10.8 cm)</td>
			<td>ANY; ULINE is one example</td>
			<td>S-6285</td>
			<td>For 2-mm ground plant samples</td>
		</tr>
		<tr>
			<td>Corn chipper</td>
			<td>ANY; DR Chipper Shredder is one example</td>
			<td>SKU:CS23030BMN0</td>
			<td>For chipping corn biomass</td>
		</tr>
		<tr>
			<td>Corn seed</td>
			<td>ANY</td>
			<td>NA</td>
			<td>Hybrid appropriate to the region</td>
		</tr>
		<tr>
			<td>Disposable shoe cover</td>
			<td>ANY; Boardwalk is one example</td>
			<td>BWK00031L</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol 200 Proof</td>
			<td>ANY; Decon Laboratories Inc. is one example</td>
			<td>2701TP</td>
			<td></td>
		</tr>
		<tr>
			<td>Fabric bags with drawstring (90x60 cm)</td>
			<td>ANY</td>
			<td>NA</td>
			<td>For plant sample collection</td>
		</tr>
		<tr>
			<td>Fertilizer Urea (46-0-0)</td>
			<td>ANY</td>
			<td>NA</td>
			<td>~0.366 atom % 15N</td>
		</tr>
		<tr>
			<td>Hand rake</td>
			<td>ANY; Fastenal Company is one example</td>
			<td>5098-63-107</td>
			<td></td>
		</tr>
		<tr>
			<td>Hand sickle</td>
			<td>ANY; Home Depot is one example</td>
			<td>NJP150</td>
			<td>For plant sample collection</td>
		</tr>
		<tr>
			<td>Hand-held soil probe</td>
			<td>ANY; AMS is one example</td>
			<td>401.01</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydraulic soil probe</td>
			<td>ANY; Giddings is one example</td>
			<td>GSPS</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrochloric acid, 12N</td>
			<td>Ricca Chemical</td>
			<td>R37800001A</td>
			<td></td>
		</tr>
		<tr>
			<td>Jar mill</td>
			<td>ANY; Cole-Parmer is one example</td>
			<td>SI-04172-50</td>
			<td></td>
		</tr>
		<tr>
			<td>Laboratory Mill</td>
			<td>Perten</td>
			<td>3610</td>
			<td>For grinding grain</td>
		</tr>
		<tr>
			<td>Microbalance accurate to four decimal places</td>
			<td>ANY; Mettler Toledo is one example</td>
			<td>XPR2</td>
			<td></td>
		</tr>
		<tr>
			<td>N95 Particulate Filtering Facepiece Respirator</td>
			<td>ANY, ULINE is one example</td>
			<td>S-9632</td>
			<td></td>
		</tr>
		<tr>
			<td>Neoprene or butyl rubber gloves</td>
			<td>ANY</td>
			<td>NA</td>
			<td>For working in HCl acid bath</td>
		</tr>
		<tr>
			<td>Paper hardware bags (13.3x8.7x27.8 cm)</td>
			<td>ANY; ULINE is one example</td>
			<td>S-8530</td>
			<td>For soil samples and corn grain</td>
		</tr>
		<tr>
			<td>Plant grinder</td>
			<td>ANY; Thomas Wiley Model 4 Mill is one example</td>
			<td>1188Y47-TS</td>
			<td>For grinding chipped corn biomass to 2-mm particles</td>
		</tr>
		<tr>
			<td>Plastic tags</td>
			<td>ULINE</td>
			<td>S-5544Y-PW</td>
			<td>For labeling fabric bags and microplot stalk bundles</td>
		</tr>
		<tr>
			<td>Sodium hydroxide pellets, ACS</td>
			<td>Spectrum Chemical</td>
			<td>SPCM-S1295-07</td>
			<td></td>
		</tr>
		<tr>
			<td>Soil grinder</td>
			<td>ANY; AGVISE stainless steel grinder with motor is one example</td>
			<td>NA</td>
			<td>For grinding soil to pass through a 2-mm sieve</td>
		</tr>
		<tr>
			<td>Tin capsule 5x9 mm</td>
			<td>Costech Analytical Technologies Inc.</td>
			<td>041061</td>
			<td></td>
		</tr>
		<tr>
			<td>Tin capsule 9x10 mm</td>
			<td>Costech Analytical Technologies Inc.</td>
			<td>041073</td>
			<td></td>
		</tr>
		<tr>
			<td>Urea (46-0-0)</td>
			<td>MilliporeSigma</td>
			<td>490970</td>
			<td>10 atom % 15N</td>
		</tr>
	</tbody>
</table>

microplot design and plant and soil sample preparation for 15nitrogen analysis

许多氮肥研究评估处理对季末测量（如谷物产量或累计 N 损失）的总体影响。需要采用稳定的同位素方法，跟踪和量化通过土壤作物系统获得N（FDN）的肥料的命运。本文的目的是描述一种小图研究设计，利用非封闭15个N富集微图，在两个生长季节进行多个土壤和植物采样事件，并提供样品收集、处理和处理方案，用于总共15个N分析。这些方法通过一项从明尼苏达州中南部种植到玉米的复制研究进行演示（Zea Mays L.）。每次处理包括六排玉米（76厘米的行间距）15.2米长，一端嵌入一个微图（2.4米 x 3.8米）。肥料级尿素在种植时以135公斤N+ha-1施用，而微图在种植过程中多次采集了富集量至5原子%15N的尿素，并注意使用单独的工具，并在所有过程中使用物理分离未富集和浓缩的样品，尽量减少交叉污染。土壤和植物样品干燥，地面通过2毫米的屏幕，然后地面到面粉一样一致性使用辊罐磨。跟踪器研究需要额外的规划、样品处理时间和人工，并且比传统的 N 研究产生更高的 15N 浓缩材料和样品分析成本。然而，使用质量平衡方法，具有多个季节采样事件的跟踪研究使研究人员能够通过土壤作物系统估计 FDN 分布，并估计系统中对 FDN 的下落不明。

本文提供的结果来自2015年位于明尼苏达州瓦塞卡附近的明尼苏达大学南方外展研究中心的一个现场。该基地在 2015 年以前被管理为玉米大豆 +甘氨酸最大值 （L.） Merr] 旋转，但在 2015 和 2016 生长季节作为玉米玉米轮作进行管理。土壤是一个Nicollet粘土土（细洛米，混合，超活性，梅西阿基克哈普卢多斯）-韦伯斯特粘土土（细洛米，混合，超活性，中西泰皮克恩多阿...

Watch this Scientific Journal Video about Microplot Design and Plant and Soil Sample Preparation for 15Nitrogen Analysis at JoVE.com

Microplot Design and Plant and Soil Sample Preparation for 15Nitrogen Analysis

介绍了用于15N 示踪剂研究的微图设计，以适应多个季节内植物和土壤采样事件。提出了用于15N分析的土壤和植物样品收集和处理程序，包括研磨和称重方案。

微图设计及植物和土壤样品制备，进行15次氮气分析

Many&#160;nitrogen fertilizer studies evaluate the overall effect of a treatment on end-of-season measurements such as grain yield or cumulative N losses. ...

这种方法可以帮助研究人员量化肥料驱动氮对土壤作物系统的影响，并回答有关氮的使用效率的问题。该技术的主要优点是，它允许在连续两个生长季节进行多个季节土壤和植物采样事件。这种方法可以帮助我们更好地了解矿化和动员的氮循环过程，以改进氮肥管理指南。为了建立一个田地地块，种植6个间距为76厘米的玉米排，最终的15.2倍4.6米的地块尺寸。从长尺寸的每一端建立1.5米的边界区域，并在取样和收获区毗邻的另一个1.5米长的边界区域。将第二排和第三排指定为季节植物和土壤取样区，第四行和第五行指定为玉米谷物产量的收获区。建立一个以宽度尺寸为中心的 2.4 边 3.8 米的微图区域，收集所有富氮植物和土壤样本，在长度和宽度尺寸上留下 38 米的未采样边框，以尽量减少任何边缘影响。然后用不同颜色的标志绘制处理图和微图角。访问微地块时佩戴鞋罩，尽量减少微地块步行流量，以防止未富密取样区域受到污染，在退出微地块区域时去除脚罩。施用氮-15富肥，将常规尿素中10原子氮-15富集尿素稀释至5原子%氮富尿素，将尿素溶解在两升脱氧水中，确保尿素肥料均匀浓缩。使用经过校准的背包二氧化碳喷雾器将氮-15浓缩尿素溶液均匀地应用于微图。然后在施用后24小时内加入含有肥料的尿素，并采用轻质耕作、手铲或64厘米灌溉，以最大限度地降低挥发性损失潜力。在每个取样阶段，从取样区内采集6个地上、氮-15未富玉米植物复合样品，从氮-15富集微地块采集6个地上玉米植物复合样品。将 VH 和 R1 切到地面生物量之上，将切碎的生物量放入标记袋或干燥，并在 60 摄氏度下强制空气烤箱，直到恒定质量。记录生物质干重，彻底混合和研磨100至200克的干燥植物材料，直到它可以通过两毫米筛。然后彻底混合地面材料，将子样品存放在贴有标签的硬币信封中，以进行进一步处理。对于土壤样品处理，在施肥后8天内，使用手探针从VH和R1的未富量取样区采集4个直径1.8厘米的复合土壤样品，并采用单独的手探针从微图中采集15芯1.8厘米直径复合土壤样品。将每个复合土壤样品均质化到桶中，并放置在预先标记的纸袋中。然后在强制空气烤箱中以 35 摄氏度的温度下干燥土壤样品，直到恒定质量，然后研磨每个样品，直到它能穿过两毫米筛。在实验室中进行样品处理，在60摄氏度的烤箱中将地面计划样品在60摄氏度的烤箱中过夜，然后单独研磨干燥的植物和土壤样品，在滚筒罐中以四倍的g进行6至24小时，直到样品获得一致性等细面粉。然后将细磨材料转移到清洁标记的 20 毫升硅化小瓶中。要确定每个样品中总浓度和氮-15浓度，戴上亚硝酸盐手套，首先使用实验室湿巾和乙醇清洁微量表、工作表面、铲和钳子。将清洁的餐具放在实验室的擦拭上，然后用钳子轻轻打开样品胶囊的开口。烤箱和释放修改的胶囊一到两毫米以上的微量锅和撕裂胶囊。使用钳子将胶囊返回到干净的工作表面，并使用铲子小心地将所需的细磨样品材料质量添加到胶囊中。使用钳子慢慢压接加载胶囊的三分之一，并折叠起来密封。继续折叠和压缩胶囊，注意不要刺穿或撕裂锡，直到获得球形形状。使用钳子将包裹的胶囊从一厘米高处多次掉落到干净的深色表面上，以检查是否泄漏。如果没有灰尘出现，像刚刚演示的一样称重样品，将胶囊放在 96 井板的一个井中，记录井的位置。在每个样品封装之间，用乙醇和实验室湿巾清洁每个器皿和表面，特别注意铲和钳的边缘。在本次代表性分析中，上述玉米生物质样品中的肥料源氮浓度在生长季节较早时最大，且随着每次连续采样期而降低。然而，土壤衍生氮一直是地上生物质氮的最大部分，这说明了土壤氮供应对最佳玉米生长的重要性。在第一年的生理成熟期，大约27%的地上生物质氮是肥料，在谷物、粗壮和球类中观察到的比例相似。第二年生理成熟时，在上述地面生物量中只回收了2%的第一年肥料衍生氮。第一年每公顷肥料约1.6公斤，从谷物中出口氮。在施肥的8天内，大部分肥料的氮气都如预期的那样位于土壤剖面的15厘米以上。然而，每公顷大约22公斤氮已经进入更深的深处，而4至10%的肥料氮则下落不明。事实上，到第一年和第二年结束时，土壤玉米系统中的肥料源氮占不到50%，而其余氮要么流失到环境中，要么浸出低于90厘米的土壤样本深度。尝试此程序时，应格外小心，避免交叉污染，以免使结果失效。可以进一步分析土壤的无机和有机部分，以增进我们对氮循环动力学的了解。按植物零件分析的植物样品可用于告知我们对氮吸收和易位情况的了解。

Research

JoVE Journal

Environment

Microplot Design and Plant and Soil Sample Preparation for 15Nitrogen Analysis

Design and Operation of a Continuous 13C and 15N Labeling Chamber for Uniform or Differential, Metabolic and Structural, Plant Isotope Labeling

Design and Operation of a Continuous 13C and 15N Labeling Chamber for Uniform or Differential, Metabolic and Structural, Plant Isotope Labeling

设计一个连续和操作<sup&gt; 13</sup&gt; C和<sup&gt; 15</sup&gt;Ñ贴标商会统一或差分，代谢和结构，植物同位素标记

Tracing rare stable isotopes from plant material through the ecosystem provides the most sensitive information about ecosystem processes; from CO2 fluxes ...

科研

环境科学

Design and Construction of an Urban Runoff Research Facility

设计一个城市径流研究设施的建设

As the urban population increases, so does the area of irrigated urban landscape. Summer water use in urban areas can be 2-3x winter base line water use ...

Experimental Protocol for Manipulating Plant-induced Soil Heterogeneity

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 ...

A Gusseted Thermogradient Table to Control Soil Temperatures for Evaluating Plant Growth and Monitoring Soil Processes

一个插角Thermogradient表来控制土壤温度为评估植物生长和监测土壤过程

Thermogradient tables were first developed in the 1950s primarily to test seed germination over a range of temperatures simultaneously without using a ...

Protocol for Microplastics Sampling on the Sea Surface and Sample Analysis

协议塑料微粒采样的海面和样品分析

Microplastic pollution in the marine environment is a scientific topic that has received increasing attention over the last decade. The majority of ...

Nanopore DNA Sequencing for Metagenomic Soil Analysis

基因土壤分析的纳米 DNA 测序

This article describes the steps for construction of a DNA library from soil, preparation and use of the nanopore flow cell, and analysis of the DNA ...

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

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 ...

High-throughput Siderophore Screening from Environmental Samples: Plant Tissues, Bulk Soils, and Rhizosphere Soils

从环境样品中筛选高通量的安德森菌: 植物组织、散装土壤和根际土壤

Siderophores (low-molecular weight metal chelating compounds) are important in various ecological phenomenon ranging from iron (Fe) biogeochemical cycling ...

Sample Preparation Method of Scanning and Transmission Electron Microscope for the Appendages of Woodboring Beetle

木钻甲虫附着物扫描和透射电子显微镜的样品制备方法

This report described sample preparation methods that scanning and transmission electron microscope observations, demonstrated by preparing appendages of ...

Measuring Phosphorus Release in Laboratory Microcosms for Water Quality Assessment

测量实验室微量微生物中的磷释放,用于水质评估

Phosphorus (P) is a critical limiting nutrient in agroecosystems requiring careful management to reduce transport risk to aquatic environments. Routine ...