This material is based upon work supported by the National Science Foundation under Grant Number 1215858, by the US Department of Agriculture under Grant Number 2013-68002-20525, and by the US Department of Energy Great Lakes Bioenergy Research Center &#8211; DOE BER Office of Science (DE-FC02-07ER64494) and DOE OBP Office of Energy Efficiency and Renewable Energy (DE-AC05-76RL01830). In-field video and images were recorded at the Wisconsin Integrated Cropping System Trial project of the University of Wisconsin&#8211;Madison. The authors are grateful to Ryan Curtin for skillful videography and editing.

<ol>
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A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Micrometeorological+and+chamber+methods+for+measurement+of+nitrous+oxide+fluxes+between+soils+and+the+atmosphere:+Overview+and+conclusions.">Micrometeorological and chamber methods for measurement of nitrous oxide fluxes between soils and the atmosphere: Overview and conclusions.</a> Journal of Geophysical Research: Atmospheres. 99 (1984-2012), 16541-16548 (1984).</li><li>Bouwman, A. F., Boumans, L. J. M., Batjes, N. 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S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chamber+Measurements+of+Soil+Nitrous+Oxide+Flux:+Are+Absolute+Values+Reliable.">Chamber Measurements of Soil Nitrous Oxide Flux: Are Absolute Values Reliable.</a> Soil Science Society of America Journal. 72 (2), 331 (2008).</li><li>Robertson, G. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Greenhouse+Gases+in+Intensive+Agriculture:+Contributions+of+Individual+Gases+to+the+Radiative+Forcing+of+the+Atmosphere.">Greenhouse Gases in Intensive Agriculture: Contributions of Individual Gases to the Radiative Forcing of the Atmosphere.</a> Science. 289 (5486), 1922-1925 (2000).</li><li>Parkin, T. B., Venterea, R. T., Follet, R. 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R., de Klein, C., deKlein, C., Harvey, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deployment+Protocol.+In:+Nitrous+Oxide+Chamber+Methodolog+Guidelines.">Deployment Protocol. In: Nitrous Oxide Chamber Methodolog Guidelines.</a> Ministry for Primary Industries. (3), (2013).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fundamentals+of+Gas+Chromatography.">Fundamentals of Gas Chromatography.</a> Agilent Technologies, Inc. , 1-60 (2002).</li><li>Holland, E. A., Robertson, G. P., Greenberg, J., Groffman, P. M., Boone, R. D., Gosz, J. R., Robertson, G. P., Coleman, D. C., Bledsoe, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Soil+CO2,+N2O,+and+CH4+Exchange.">Soil CO2, N2O, and CH4 Exchange.</a> Standard Soil Methods for Long-Term Ecological Research. , (1999).</li><li>Venterea, R. T., Burger, M., Spokas, K. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nitrogen+Oxide+and+Methane+Emissions+under+Varying+Tillage+and+Fertilizer+Management.">Nitrogen Oxide and Methane Emissions under Varying Tillage and Fertilizer Management.</a> Journal of Environment Quality. 34 (5), 1467 (2005).</li><li>Hutchinson, G. L., Mosier, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+soil+cover+method+for+field+measurement+of+nitrous+oxide+fluxes.">Improved soil cover method for field measurement of nitrous oxide fluxes.</a> Soil Science Society of America Journal. 45 (2), 311-316 (1981).</li><li>Pedersen, A. R., Petersen, S. O., Vinther, F. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stochastic+diffusion+model+for+estimating+trace+gas+emissions+with+static+chambers.">Stochastic diffusion model for estimating trace gas emissions with static chambers.</a> Soil Science Society of America Journal. 65, 49-58 (2001).</li><li>Pedersen, A. R., Peterson, S. O., Schelde, 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+comprehensive+approach+to+soil-atmosphere+trace-gas+flux+estimation+with+static+chambers.">A comprehensive approach to soil-atmosphere trace-gas flux estimation with static chambers.</a> European Journal of Soil Science. 61, 888-902 (2010).</li><li>Wagner, S. W., Reicosky, D. C., Alessi, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regression+models+for+calculating+gas+fluxes+measured+with+a+closed+chamber.">Regression models for calculating gas fluxes measured with a closed chamber.</a> Agronomy Journal. 89, 279-284 (1997).</li><li>Livingston, G. P., Hutchinson, G. L., Spartalian, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trace+gas+emission+in+chambers.">Trace gas emission in chambers.</a> Soil Science Society of America Journal. 70, 1459-1469 (2006).</li><li>Venterea, R. T., Parkin, T. B., Cardenas, L., Petersen, S. O., Pedersen, A. R., deKlein, C., Harvey, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Data+Analysis+Considerations.+In:+Nitrous+Oxide+Chamber+Methodology+Guidelines.">Data Analysis Considerations. In: Nitrous Oxide Chamber Methodology Guidelines.</a> Ministry for Primary Industries. (6), (2013).</li><li>Grace, P., van der Weerden, T. J., Kelly, K., Rees, R. M., Skiba, U. M., deKlein, C., Harvey, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated+Greenhouse+Gas+Measurement+in+the+Field.+In:+Nitrous+Oxide+Chamber+Methodology+Guidelines.">Automated Greenhouse Gas Measurement in the Field. In: Nitrous Oxide Chamber Methodology Guidelines.</a> Ministry for Primary Industries. , (2013).</li><li>Alfaro, M. A., Giltrap, D., Topp, C. F. E., de Klein, C., deKlein, C., Harvey, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+to+Report+Your+Experimental+Data.+In:+Nitrous+Oxide+Chamber+Methodology+Guidelines.">How to Report Your Experimental Data. In: Nitrous Oxide Chamber Methodology Guidelines.</a> Ministry for Primary Industries. , (2013).</li></ol>

The authors have nothing to disclose.

<html> הגישה מבוססת תא סטטי שתוארה כאן היא שיטה יעילה למדידת שטף גזי חממה ממערכות קרקע. הפשטות היחסית של מרכיביו הופכת אותו מתאימה במיוחד לתנאים או מערכות שבהן יותר שיטות תשתית עתירות אינן מעשיות. על מנת להפיק נתונים באיכות גבוהה, לעומת זאת, הגישה הקאמרית סטטי חייבת להתבצע עם תשומת לב קפדנית לעיצוב ניסיוני 6. שיקול בולט אחד שיש לקחת בחשבון הוא את השונות המרחבית של נתיבי גז קרקע, אשר עלול לגרום לשונות גבוהות בין מדידות המבוסס על תא לשכפל. בתכנון ניסויים, ולכן, חשוב לכלול מספיק חזרות כדי לספק כוח מתאים לניתוח סטטיסטי. פשרות עשויות להתקיים בין מספר הטיפולים שניתן ללמוד תוך שמירה על שכפול מספיק, ומינימום של ארבע חזרות לכל טיפול הוא קו מנחה כללי 14. ontent &quot;&gt; אם והנתיבים נמדדו ישמשו כדי לאמוד את הפליטה יומית, וריאציות יומי בטמפרטורת אוויר, טמפרטורת קרקע, ופליטת גזים חייבים להילקח בחשבון. אם מטרות מחקר דורשות מדידות שתתקבל באמצע הבוקר כאשר טמפרטורות משקפות ממוצעים יומי, החלון המוגבל לדגימה עשוי להשפיע על מספר התאים שיתכן יכולים להיות פיקוח. תמורה נוספת שמוערכת היא ההשפעה שהכללה או אי הכללה של שורשי צמח ומעל לביומסה קרקע תהיה בנתיבי גז. יחסי מיקום הלשכה לשתול רקמות להשפיע על הפרשנות של נתונים שטף, במיוחד במקרה של ה-CO 2 שבו לא רק נשימה של חיידקים, אלא גם שורש ולירות נשימה ופוטוסינתזה חייבת להיות כראוי מאוזנות. לדיון נוסף בגורמים אלה, ראו פרקין וVenterea 8. כפי שצוין קודם לכן, וריאציות רבות על מתודולוגיה זו קיימות, כולל עיצוב תא ודגימהנפח. וריאציה אחת כזו היא בשיטה המועסקות על מנת להעביר דגימות בין המזרק ובקבוקון אוסף. הטכניקה המתוארת כאן גלי ראשונה בקבוקון האוסף עם מדגם לפני מילוי הבקבוקון ללחץ חיובי 5. טכניקה נפוצות יותר היא ההעברה של דגימות ממזרקים לבקבוקונים, כי כבר מראש פינה-באמצעות משאבת ואקום, ואת השימוש בבקבוקונים שאינם מפונים ללא שטיפה דווח 8,17 גם. עוד נקודה משמעותית שבו מגוון של גישות קיימת היא בניתוח הנתונים והבחירה של מודל השטף המתאים ביותר למערכת תחת מחקר. בנוסף לשיטת רגרסיה ליניארית שתוארה כאן, מודלים שאינם ליניארי עשויים גם להיות מועסקים, ובמיוחד בזמנים פריסה ארוכים יותר נמצאים בשימוש. מודלים אלה כוללים את האלגוריתם שפותח על ידי הצ&#39;ינסון וMosier 18 ונגזרות ממנו 19,20, ההליך ריבועית שתואר על ידי וגנר ואח&#39;. 21, והלא יציביםאומדן שטף diffusive מדינה תואר על ידי ליווינגסטון et 22 אל. לדיון מעמיק במודלי שטף שאינו ליניארי, עיין בפרקין et al. 12 וVenterea אח&#39; 23. שיטות דומות לגישה הקאמרית סטטית כוללות שימוש במערכות מדידת זרימה דרך אינפרא אדום עם העברה פורייה ספקטרומטריית (FTIR) כחלופי למזרק כרומטוגרפיה דגימה וגז, כמו גם אוטומציה של סגירת תא ודגימה באמצעים שונים. מערכות אוטומטיות תאפשר מדידות תכופות יותר עם אנשים מופחתים, אלא גם דורשות השקעות בתשתית נוספות. גרייס et al. 24 לספק סיכום נרחב של אפשרויות ופשרות בN מבוסס תא האוטומטי 2 O מדידה. אפיון של שטף גזי חממה משני מנוהל ומערכות טבעיות חשוב ליידע מודלים מבוססי תהליך, להבין את ההשפעות של managemeשיטות עבודה וNT להודיע ​​אסטרטגיות להפחתה, ולתמוך חשבונאי גלובלי ושינויי אקלים דוגמנות. וכך, בעוד מחקרים בודדים הם אינפורמטיבי בקנה המידה המקומי, הרבה ערך נוסף נגזר דרך לתרום ל, וציור מ, גוף עולמי של ידע על חילוף גזים בין הנוף והאווירה. זה מפתח, אם כן, הנתונים שייאספו ודיווחו באופן שמבטיח אריכות ימים ויכולת פעולה הדדית עם בסיס הידע הרחב יותר. זה כולל שיטות עבודה מומלצות הבא על מנת להבטיח איכות נתונים, כמו גם אוסף של צעדים נלווים ודיווח המקיף של מטה כדי לאפשר הרחבה של ממצאים מעבר למחקרים נפרדים. הנחיות מצוינות לדיווח הנתונים זמינות מפרויקט GRACEnet וGRA 25.

Understanding the contributions of both human activities and natural systems to radiative properties of the atmosphere is an area of critical importance as we strive to mitigate anthropogenic contributions to the greenhouse effect. In addition to carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) are also potent GHGs, accounting for an estimated 7% and 19% of global warming, respectively, with the majority of emissions coming from landscape sources1,2. These range from managed systems such as agricultural fields, rice paddies, and landfills, to natural systems such as forest floors, wetlands, and termite mounds. Accurate measurement, supporting well-informed modeling of such landscape-based emissions is critical in order to understand the drivers of climate change as well as to identify mitigation opportunities.
A variety of greenhouse gas measurement strategies exist, each with their own strengths and weaknesses2-5. Mass balance techniques rely on wind-based dispersion of gases and are suited to measurement of flux from small, well-defined sources such as landfills and animal paddocks. Micrometeorological approaches such as eddy covariance are based on real-time direct measurement of vertical gas flux, and can provide direct measurements over large areas. However, homogeneity in source topography is an implicit assumption (in that measurements yield a mean for the area under study), and costly infrastructure can limit deployment possibilities. Finally, chamber-based methods focus on change in gas concentration at the soil surface by sampling from a restricted above ground headspace. They allow measurements to be obtained from small areas and numerous treatments, but are subject to high coefficients of variation due to spatial variation in soil gas flux.
Here we discuss the most prevalent and easily implemented form of chamber-based measurement, utilizing the type of closed chambers without air flow-through commonly referred to as &#8220;static&#8221; or &#8220;non-steady-state non-flow-through&#8221; chambers. In this approach, gas emissions from the soil surface are trapped within a vented chamber, and rates of flux are determined by measuring the change in gas concentration over time within the chamber headspace. The static chamber technique has been widely deployed across both managed and natural landscapes and underpins the bulk of data reporting soil-based flux of greenhouse gases, particularly N2O6,7. It is ideally suited to the study of small experimental plots, diverse sites over variable terrain, or in other situations where multiple distinct locations must be studied without significant infrastructure investments. Typical experimental uses might include the exploration of alternative landscape management practices and their impact on soil-based CO2, N2O, and/or CH4 emissions, examination of landscape-based flux dynamics under artificially induced climate change scenarios such as warming and rainfall exclusion/supplementation, or the descriptive study of natural and agricultural ecosystems and subsystems.
As a critical tool in GHG measurement and flux estimation, the static chamber method has been thoroughly evaluated, and significant efforts have been made towards standardization of techniques and harmonization of data reporting4,6,8,9. Of particular note are the detailed reviews and guidelines produced by the U.S. Department of Agriculture &#8211; Agricultural Research Service&#8217;s Greenhouse gas Reduction through Agricultural Carbon Enhancement network (GRACEnet)8 and by the Global Research Alliance on Agricultural Greenhouse Gases (GRA)9. Such guidelines provide an invaluable resource and platform for coordination, as ultimately the interoperability of data from a myriad of studies is critical for scaling up local findings to global modeling, and for translating research results into viable mitigation strategies.
GRACEnet, GRA, and other reviews also highlight the fact that specific techniques in static chamber-based greenhouse gas flux measurement are extremely diverse, with significant methodological variations possible at nearly every step of the way, including chamber design, temporal and spatial deployment, sampling volumes, sample analysis, and flux calculations. The method described here presents one possible variant, while showcasing best practices and highlighting critical considerations for the generation of high quality, broadly transferrable data. It is intended to provide an accessible overview of this standardized procedure, and a platform from which to explore further nuances and variations described in the literature.

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			<td height="42" style="height:42px;width:332px;">5.9 ml soda glass flat bottom 55 x 15.5 mm</td>
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			<td style="width:123px;">719W</td>
			<td style="width:413px;">Collection vials</td>
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			<td height="42" style="height:42px;width:332px;">16.5 mm screw caps with pierceable rubber septum</td>
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			<td style="width:123px;">VC309</td>
			<td style="width:413px;">Caps for&#160; vials</td>
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			<td height="21" style="height:21px;width:332px;">90-well plastic vial rack, 17.1 mm well I.D.</td>
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			<td style="width:413px;">Rack for organizing vials</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:332px;">Regular bevel needles 23G x 1&#34;</td>
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			<td style="width:123px;">305193</td>
			<td style="width:413px;">Needles for sample collection</td>
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			<td height="42" style="height:42px;width:332px;">Stopcocks with luer connections, 1-way, male slip</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:332px;">30 ml syringe, slip tip</td>
			<td style="width:73px;">BD</td>
			<td style="width:123px;">309651</td>
			<td style="width:413px;">Syringes for sample collection</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:332px;">Stopwatch or timer</td>
			<td style="width:73px;">Various</td>
			<td style="width:123px;">N/A</td>
			<td style="width:413px;">For timing field sampling</td>
		</tr>
		<tr height="83">
			<td height="83" style="height:83px;width:332px;">Stainless steel or galvanized utility pans with rim, or fabricated stainless steel or PVC chambers and lids, dimensions as appropriate to experimental system</td>
			<td style="width:73px;">Various</td>
			<td style="width:123px;">N/A</td>
			<td style="width:413px;">Chamber anchor and lid - bottom cut out of anchor, holes for septum and vent tubing bored in lid</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:332px;">Gray butyl stoppers 20 mm</td>
			<td style="width:73px;">Wheaton</td>
			<td style="width:123px;">W224100-173</td>
			<td style="width:413px;">Chamber septa for syringe sampling - insert into hole bored in lid top</td>
		</tr>
		<tr height="83">
			<td height="83" style="height:83px;width:332px;">Tygon tubing 4.0 mm I.D. x 5.6 mm O.D.</td>
			<td style="width:73px;">Sigma-Aldrich</td>
			<td style="width:123px;">Z685623</td>
			<td style="width:413px;">Chamber vent tubing - insert in hole bored in lid side, flush with exterior, approximately 25 cm coiled in lid interior (a 1ml syringe tip may be used as an attachement mechanism)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:332px;">Adhesive foam rubber tape or HDPE O-ring</td>
			<td style="width:73px;">Various</td>
			<td style="width:123px;">N/A</td>
			<td style="width:413px;">Chamber sealing mechanism - fastened to underside of lid rim</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:332px;">Reflective&#160; insulation, 0.3125&#34; thickness</td>
			<td style="width:73px;">Lowe&#39;s</td>
			<td style="width:123px;">409818</td>
			<td style="width:413px;">Insulating and reflective coating - affix to exterior of chamber lid</td>
		</tr>
		<tr height="62">
			<td height="62" style="height:62px;width:332px;">Large metal binder clips, 2&#34; size with 1&#34; capacity, or manufactured draw latch as appropriate</td>
			<td style="width:73px;">Staples / McMaster</td>
			<td style="width:123px;">831610 (Staples) / 1863A21 (McMaster)</td>
			<td style="width:413px;">Lid attachment mechanism - for clamping lid to anchor during sampling</td>
		</tr>
		<tr height="104">
			<td height="104" style="height:104px;width:332px;">Gas chromatography equipment fitted with electron capture detector for nitrous oxide, infrared gas analyzer or thermal conductivity detector for carbon dioxide, flame ionization detector for methane</td>
			<td style="width:73px;">Various</td>
			<td style="width:123px;">N/A</td>
			<td style="width:413px;">For sample analysis</td>
		</tr>
	</tbody>
</table>

measurement of greenhouse gas flux from agricultural soils using static chambers

Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the biogeochemical drivers of climate change and to the development and evaluation of GHG mitigation strategies based on modulation of landscape management practices. The static chamber-based method described here is based on trapping gases emitted from the soil surface within a chamber and collecting samples from the chamber headspace at regular intervals for analysis by gas chromatography. Change in gas concentration over time is used to calculate flux. This method can be utilized to measure landscape-based flux of carbon dioxide, nitrous oxide, and methane, and to estimate differences between treatments or explore system dynamics over seasons or years. Infrastructure requirements are modest, but a comprehensive experimental design is essential. This method is easily deployed in the field, conforms to established guidelines, and produces data suitable to large-scale GHG emissions studies.

לפני תחילת פרויקט מחקר בתאי סטטי, חשוב להבין את זרימת העבודה הכללית, וארגון בסיליקו, שדה ואלמנטים מבוססי מעבדה (איור 1). המסופק על תכנון זהיר ניסיוני וכיול מערכת (איור 2), ניתוח נתונים בדרך כלל להיות פשוט יחסית. שיעור של שטף נקבע לכל תא וזמן דגימה על ידי רגרסיה של זמן על ידי ריכוז תוך שימוש במודל שטף נקבע מראש מתאים למערכת (איור 3). עם זאת, גם שיטות עבודה מומלצות הבא, ייתכן ויהיה קושי, ובקרת איכות של הנתונים גולמיים היא קריטית. לדוגמא, כישלון של חותם קאמרי או בקבוקוני מדגם דולפים יכול לגרום לערכי ריכוז חריגים. אלה מזוהים בקלות באמצעות בדיקה ויזואלית של חלקות ריכוז סדרת הזמן (איור 4), עם סדרת 2 זמן CO לעתים קרובות משמשת בעיקר usefuמחוון l בשל השטף בדרך כלל חזק יותר ומתמשך של CO 2 בהשוואה ל, סמוך לזיהוי מגבלה לפעמים זניחה, או אפילו נתיבים שליליים של N 2 O או 4 CH. ברגע שאיכות הנתונים כבר אישרה, תוצאות עשויות לשמש כדי להשוות דינמיקת שטף גז בין טיפולים או במהלך עונה (איור 5). כפי שניתן לראות מערכי שטף חודשים מאי ויוני וברים שגיאה, הווריאציה שנגרמה על ידי הטרוגניות המרחבית של שטף עשויה להיות משמעותית, ובולט יותר בתנאי ייצור שיעורים גבוהים של שטף. השתנות כזה היא לא יוצאת דופן, ומדגישות את החשיבות של שכפול מספיק בטכניקה זו. <img alt="איור 1" src="/files/ftp_upload/52110/52110fig1highres.jpg" width="600" /> איור 1. סקירת זרימת עבודה. אלמנטים שונים של פרוטוקול זה תבוצע בשלב התכנון, בשדה, במעבדה, ואניסיליקו n. חצים מצביעים על הרצף של זרימת עבודה, החל מעיצוב תא (ובנייה במידת צורך), וכלה בניתוח הנתונים. תיבות / חצים מרובים בין דגימת שדה וניתוח מדגם מייצגים את האפשרות של תאריכי דגימה מרובים במהלך ניסוי. <img alt="איור 2" src="/files/ftp_upload/52110/52110fig2highres.jpg" width="400" /> איור 2. עיתוי לדוגמא. ערכת עיתוי דוגמא לאיסוף דגימות מתאים מרובים בו זמנית. מספרי הלשכה מסומנים בנקודות משמאל ופעם בראש, עם זמני דגימה מופיעים בדקות שלמות בתוך הרשת. בדוגמא זו, ארבע סדרות זמן נפרדות של 36 דקות כל אחד (אחד לכל תא) מתבצעות בתוך המרחב של 46 דקות, עם 12 מרווח דק בין נקודות זמן בתוך סדרה, ו2 זמן הליכה דקות בין תאים. לדוגמא היפותטית זו, suitability סדרת זמן 36 דקות של היה נקבע על ידי כיול קודם. אמנם עיתוי מחולק באופן שווה אין צורך, זה בדרך כלל מפשט את תכנית הדגימה. לחלופין, חוקרים יכולים בנפרד להקליט כל timepoint דגימה כדי לקבוע מרווחי דגימה. <img alt="איור 3" src="/files/ftp_upload/52110/52110fig3highres.jpg" width="600" /> איור 3. חישוב שטף. סדרה טיפוסית סטטית קאמרי זמן, בהיקף של N 2 O ריכוזים שנמדדו בארבע נקודות זמן במהלך תקופת דגימה 36 דקות. רגרסיה ליניארית מוצגת, השיפוע של אשר מניב קצב זרימה. <img alt="איור 4" src="/files/ftp_upload/52110/52110fig4highres.jpg" width="600" /> שליטת 4. איכות איור. מותאם סדרת זמן מאותו הסט של דגימות אבל גזים שונים מוצגות בWHIדליפת בקבוקון ch זוהתה על ידי בדיקה חזותית (נקודה אדומה).) 2 ריכוז CO לאורך זמן. ב &#39;) N 2 O ריכוז לאורך זמן. <img alt="איור 5" src="/files/ftp_upload/52110/52110fig5highres.jpg" width="600" /> שיעור איור 5. תוצאות סינתזה. N 2 O שטף משדה חקלאי במהלך עונת גידול אחת. ערכי שטף מייצגים את הממוצע של שישה תאים, סדרת זמן ארבע נקודות משתמשים. ברים שגיאה הם שגיאה סטנדרטית.

Watch this Scientific Journal Video about Measurement of Greenhouse Gas Flux from Agricultural Soils Using Static Chambers at JoVE.com

Measurement of Greenhouse Gas Flux from Agricultural Soils Using Static Chambers

This article showcases the static chamber-based method for measurement of greenhouse gas flux from soil systems. With relatively modest infrastructure investments, measurements may be obtained from multiple treatments/locations and over timeframes ranging from hours to years.

מדידה של שטף גזי חממה מקרקעות חקלאיות באמצעות לשכות סטטי

Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the ...

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41.1K Views.  University of Wisconsin-Madison. This article showcases the static chamber-based method for measurement of greenhouse gas flux from soil systems. With relatively modest infrastructure investments, measurements may be obtained from multiple treatments/locations and over timeframes ranging from hours to years.

Video: Measurement of Greenhouse Gas Flux from Agricultural Soils Using Static Chambers

Determination of Microbial Extracellular Enzyme Activity in Waters, Soils, and Sediments using High Throughput Microplate Assays

Much of the nutrient cycling and carbon processing in natural environments occurs through the activity of extracellular enzymes released by microorganisms. Thus, measurement of the activity of these extracellular enzymes can give insights into the rates of ecosystem level processes, such as organic matter decomposition or nitrogen and phosphorus mineralization. Assays of extracellular enzyme activity in environmental samples typically involve exposing the samples to artificial colorimetric or fluorometric substrates and tracking the rate of substrate hydrolysis. Here we describe microplate based methods for these procedures that allow the analysis of large numbers of samples within a short time frame. Samples are allowed to react with artificial substrates within 96-well microplates or deep well microplate blocks, and enzyme activity is subsequently determined by absorption or fluorescence of the resulting end product using a typical microplate reader or fluorometer. Such high throughput procedures not only facilitate comparisons between spatially separate sites or ecosystems, but also substantially reduce the cost of such assays by reducing overall reagent volumes needed per sample.

Microplate based procedures are described for the colorimetric or fluorometric analysis of extracellular enzyme activity. These procedures allow for the rapid assay of such activity in large numbers of environmental samples within a manageable time frame.

קביעת מיקרוביאלית התאית אנזים הפעילות במים, קרקעות, ומשקעים באמצעות מבחני Microplate תפוקה גבוהה

Much of the nutrient cycling and carbon  processing in natural environments occurs through the activity of extracellular  enzymes released by ...

Surface Renewal: An Advanced Micrometeorological Method for Measuring and Processing Field-Scale Energy Flux Density Data

Advanced micrometeorological methods have become increasingly important in soil, crop, and environmental sciences. For many scientists without formal training in atmospheric science, these techniques are relatively inaccessible. Surface renewal and other flux measurement methods require an understanding of boundary layer meteorology and extensive training in instrumentation and multiple data management programs. To improve accessibility of these techniques, we describe the underlying theory of surface renewal measurements, demonstrate how to set up a field station for surface renewal with eddy covariance calibration, and utilize our open-source turnkey data logger program to perform flux data acquisition and processing. The new turnkey program returns to the user a simple data table with the corrected fluxes and quality control parameters, and eliminates the need for researchers to shuttle between multiple processing programs to obtain the final flux data. An example of data generated from these measurements demonstrates how crop water use is measured with this technique. The output information is useful to growers for making irrigation decisions in a variety of agricultural ecosystems. These stations are currently deployed in numerous field experiments by researchers in our group and the California Department of Water Resources in the following crops: rice, wine and raisin grape vineyards, alfalfa, almond, walnut, peach, lemon, avocado, and corn.

Surface renewal is a micrometeorological method that is being used increasingly to determine energy fluxes, but its technical complexity makes it inaccessible to a broad audience. We describe the steps needed to set up and calibrate a surface renewal field station, to acquire and process data, and to correctly interpret results.

חידוש פני השטח: שיטה מתקדם Micrometeorological למדידה ועיבוד שדה בקנה מידת אנרגיה שטף נתוני צפיפות

Advanced micrometeorological methods have become  increasingly important in soil, crop, and environmental sciences.  For many scientists without formal ...

Colorimetric Paper-based Detection of Escherichia coli, Salmonella spp., and Listeria monocytogenes from Large Volumes of Agricultural Water

This protocol describes rapid colorimetric detection of Escherichia coli, Salmonella spp., and Listeria monocytogenes from large volumes (10 L) of agricultural waters. Here, water is filtered through sterile Modified Moore Swabs (MMS), which consist&#160;of a simple gauze filter enclosed in a plastic cartridge, to concentrate bacteria. Following filtration, non-selective or selective enrichments for the target bacteria are performed in the MMS. For colorimetric detection of the target bacteria, the enrichments are then assayed using paper-based analytical devices (&#181;PADs) embedded with bacteria-indicative substrates. Each substrate reacts with target-indicative bacterial enzymes, generating colored products that can be detected visually (qualitative detection) on the &#181;PAD. Alternatively, digital images of the reacted &#181;PADs can be generated with common scanning or photographic devices and analyzed using ImageJ software, allowing for more objective and standardized interpretation of results. Although the biochemical screening procedures are designed to identify the aforementioned bacterial pathogens, in some cases enzymes produced by background microbiota or the degradation of the colorimetric substrates may produce a false positive. Therefore, confirmation using a more discriminatory diagnostic is needed. Nonetheless, this bacterial concentration and detection platform is inexpensive, sensitive (0.1 CFU/ml detection limit), easy to perform, and rapid (concentration, enrichment, and detection are performed within approximately 24&#160;hr), justifying its use as an initial screening method for the microbiological quality of agricultural water.

Colorimetric Paper-based Detection of Escherichia coli, Salmonella spp., and Listeria monocytogenes from Large Volumes of Agricultural Water

A protocol involving integrated concentration, enrichment, and end-point colorimetric detection of foodborne pathogens in large volumes of agricultural water is presented here. Water is filtered through Modified Moore Swabs (MMS), enriched with selective or non-selective media, and detection is performed using paper-based analytical devices (&#181;PAD) imbedded with bacterial-indicative colorimetric substrates.

מבוסס נייר Colorimetric איתור של<em&gt; חיידקי Escherichia</em&gt;,<em&gt; סלמונלה</em&gt; Spp., ו<em&gt; חיידקי ליסטריה</em&gt; מכמויות גדולות של מים לחקלאות

This protocol describes rapid colorimetric detection of Escherichia coli, Salmonella spp., and Listeria monocytogenes from large volumes (10 L) of ...

Measurement of H2S in Crude Oil and Crude Oil Headspace Using Multidimensional Gas Chromatography, Deans Switching and Sulfur-selective Detection

A method for the analysis of dissolved hydrogen sulfide in crude oil samples is demonstrated using gas chromatography. In order to effectively eliminate interferences, a two dimensional column configuration is used, with a Deans switch employed to transfer hydrogen sulfide from the first to the second column (heart-cutting). Liquid crude samples are first separated on a dimethylpolysiloxane column, and light gases are heart-cut and further separated on a bonded porous layer open tubular (PLOT) column that is able to separate hydrogen sulfide from other light sulfur species. Hydrogen sulfide is then detected with a sulfur chemiluminescence detector, adding an additional layer of selectivity. Following separation and detection of hydrogen sulfide, the system is backflushed to remove the high-boiling hydrocarbons present in the crude samples and to preserve chromatographic integrity. Dissolved hydrogen sulfide has been quantified in liquid samples from 1.1 to 500 ppm, demonstrating wide applicability to a range of samples. The method has also been successfully applied for the analysis of gas samples from crude oil headspace and process gas bags, with measurement from 0.7 to 9,700 ppm hydrogen sulfide.

Measurement of H2S in Crude Oil and Crude Oil Headspace Using Multidimensional Gas Chromatography, Deans Switching and Sulfur-selective Detection

A multidimensional gas chromatography method for the analysis of dissolved hydrogen sulfide in liquid crude oil samples is presented. A Deans switch is used to heart-cut light sulfur gases for separation on a secondary column and detection on a sulfur chemiluminescence detector.

מדידה של H<sub&gt; 2</sub&gt; S בנפט גולמי ונפט הגולמי Headspace שימוש רב מימדי גז כרומטוגרפיה, דיקני מיתוג ואיתור גופרית סלקטיבי

A method for the analysis of dissolved hydrogen sulfide in crude oil samples is demonstrated using gas chromatography. In order to effectively eliminate ...

Enhancement of the Initial Growth Rate of Agricultural Plants by Using Static Magnetic Fields

Electronic devices and high-voltage wires induce magnetic fields. A magnetic field of 1,300-2,500 Gauss (0.2 Tesla) was applied to Petri dishes containing seeds of Garden Balsam (Impatiens balsamina), Mizuna (Brassica rapa var. japonica), Komatsuna (Brassica rapa var. perviridis), and Mescluns (Lepidium sativum). We applied magnets under the culture dish. During the 4 days of application, we observed that the stem and root length increased. The group subjected to magnetic field treatment (n = 10) showed a 1.4 times faster rate of growth compared with the control group (n = 11) in a total of 8 days (p &#60;0.0005). This rate is 20% higher than that reported in previous studies. The tubulin complex lines did not have connecting points, but connecting points occur upon the application of magnets. This shows complete difference from the control, which means abnormal arrangements. However, the exact cause remains unclear. These results of growth enhancement of applying magnets suggest that it is possible to enhance the growth rate, increase productivity, or control the speed of germination of plants by applying static magnetic fields. Also, magnetic fields can cause physiological changes in plant cells and can induce growth. Therefore, stimulation with a magnetic field can have possible effects that are similar to those of chemical fertilizers, which means that the use of fertilizers can be avoided.

The goal of this protocol is to demonstrate the acceleration of the initial growth rate of plants by applying static magnetic fields with no external energy.

שיפור של שיעור הצמיחה הראשוני של צמחים חקלאיים באמצעות שדות מגנטיים סטטיים

Electronic devices and high-voltage wires induce magnetic fields. A magnetic field of 1,300-2,500 Gauss (0.2 Tesla) was applied to Petri dishes containing ...

Remote Sensing Evaluation of Two-spotted Spider Mite Damage on Greenhouse Cotton

The objective of this study was to evaluate a ground-based multispectral optical sensor as a remote sensing tool to assess foliar damage caused by the two-spotted spider mite (TSSM), Tetranychus urticae Koch, on greenhouse grown cotton. TSSM is a polyphagous pest which occurs on a variety of field and horticultural crops. It often becomes an early season pest of cotton in damaging proportions as opposed to being a late season innocuous pest in the mid-southern United States. Evaluation of acaricides is important for maintaining the efficacy of and preventing resistance to the currently available arsenal of chemicals and newly developed control agents. Enumeration of spider mites for efficacy evaluations is laborious and time consuming. Therefore, subjective visual damage rating is commonly used to assess density of spider mites. The NDVI (Normalized Difference Vegetation Index) is the most widely used statistic to describe the spectral reflectance characteristics of vegetation canopy to assess plant stress and health consequent to spider mite infestations. Results demonstrated that a multispectral optical sensor is an effective tool in distinguishing varying levels of infestation caused by T. urticae on early season cotton. This remote sensing technique may be used in lieu of a visual rating to evaluate insecticide treatments.

This manuscript describes a multispectral optical sensor that effectively detected damage to early season cotton artificially infested with varying densities of the two-spotted spider mite populations.

הערכת חישה מרחוק של נזק עכביש קרדית דו הבחין על כותנה חממה

The objective of this study was to evaluate a ground-based multispectral optical sensor as a remote sensing tool to assess foliar damage caused by the ...

Capturing Flow-weighted Water and Suspended Particulates from Agricultural Canals During Drainage Events

The purpose of this study is to describe the methods used to capture flow-weighted water and suspended particulates from farm canals during drainage discharge events. Farm canals can be enriched by nutrients such as phosphorus (P) that are susceptible to transport. Phosphorus in the form of suspended particulates can significantly contribute to the overall P loads in drainage water. A settling tank experiment was conducted to capture suspended particulates during discrete drainage events. Farm canal discharge water was collected in a series of two 200 L settling tanks over the entire duration of the drainage event, so as to represent a composite subsample of the water being discharged. Imhoff settling cones are ultimately used to settle out the suspended particulates. This is achieved by siphoning water from the settling tanks via the cones. The particulates are then collected for physico-chemical analyses.

Nutrients present in particulate form can contribute significantly to the overall loads in agricultural drainage waters. This study describes a novel method to capture flow-weighted water and suspended particulates from farm canal drainage over the entire duration of the drainage event.

לכידת משוקלל זרימת מים, חלקיקים מן התעלות חקלאית במהלך אירועים ניקוז

The purpose of this study is to describe the methods used to capture flow-weighted water and suspended particulates from farm canals during drainage ...

Assessment of Methane and Nitrous Oxide Fluxes from Paddy Field by Means of Static Closed Chambers Maintaining Plants Within Headspace

This protocol describes the measurement of greenhouse gas (GHG) emissions from paddy soils using the static closed chamber technique. This method is based on the diffusion theory. A known volume of air overlaying a defined soil area is enclosed within a parallelepiped cover (named &#34;chamber&#34;), for a defined period of time. During this enclosure period, gases (methane (CH4) and nitrous oxide (N2O)) move from soil pore air near their microbial source (i.e., methanogens, nitrifiers, denitrifiers) to the chamber headspace, following a natural concentration gradient. Fluxes are then estimated from chamber headspace concentration variations sampled at regular intervals throughout the enclosure and then analyzed with gas chromatography. Among the techniques available for GHG measurement, the static closed chamber method is suitable for plot experiments, as it does not require large homogenously treated soil areas. Furthermore, it is manageable with limited resources and can identify relationships among ecosystem properties, processes, and fluxes, especially when combined with GHG driving force measurements. Nevertheless, with respect to the micrometeorological method, it causes a minimal but still unavoidable soil disturbance, and allows a minor temporal resolution. Several phases are key to the method implementation: i) chamber design and deployment, ii) sample handling and analyses, and iii) flux estimation. Technique implementation success in paddy fields demands adjustments for field flooding during much of the cropping cycle, and for rice plant maintenance within the chamber headspace during measurements. Therefore, the additional elements to be considered with respect to the usual application of non-flooded agricultural soils consist of devices for: i) avoiding any unintended water disturbance that could overestimate fluxes, and ii) including rice plants within the chamber headspace to fully consider gases emitted through aerenchyma transportation.

The overall goal of this protocol is to measure greenhouse gas emissions from paddy fields using the static closed chamber technique. The measurement system needs specific adjustments due to the presence of both a permanent water layer in the field and of the plants within the chamber headspace.

הערכה של מתאן והנתיבים תחמוצת החנקן משדה אורז באמצעות חשמל סטטי סגור צ'יימברס שמירה על הצמחים בתוך קראוון

This protocol describes the measurement of greenhouse gas (GHG) emissions from paddy soils using the static closed chamber technique. This method is based ...

Experimental Study of the Relationship Between Particle Size and Methane Sorption Capacity in Shale

The amount of adsorbed shale gas is a key parameter used in shale gas resource evaluation and target area selection, and it is also an important standard for evaluating the mining value of shale gas. Currently, studies on the correlation between particle size and methane adsorption are controversial. In this study, an isothermal adsorption apparatus, the gravimetric sorption analyzer, is used to test the adsorption capacity of different particle sizes in shale to determine the relationship between the particle size and the adsorption capacity of shale. Thegravimetric method requires fewer parameters and produces better results in terms of accuracy and consistency than methods like the volumetric method. Gravimetric measurements are performed in four steps: a blank measurement, preprocessing, a buoyancy measurement, and adsorption and desorption measurements. Gravimetric measurement is presently considered to be a more scientific and accurate method of measuring the amount of adsorption; however, it is time-consuming and requires a strict measuring technique. A Magnetic Suspension Balance (MSB) is the key to verify the accuracy and consistency of this method. Our results show that adsorption capacity and particle size are correlated, but not a linear correlation, and the adsorptions in particles sieved into 40 - 60 and 60 - 80 meshes tend to be larger. We propose that the maximum adsorption corresponding to the particle size is approximately 250 &#181;m (60 mesh) in the shale gas fracturing.

We use an isothermal adsorption apparatus, the gravimetric sorption analyzer, to test the adsorption capacity of different particle sizes of shale, in order to find out the relationship between particle size and the adsorption capacity of shale.

ניסויי חקר הקשר בין גודל החלקיקים מתאן וספיחה מתוקף פצלי

The amount of adsorbed shale gas is a key parameter used in shale gas resource evaluation and target area selection, and it is also an important standard ...

Detection of Viruses from Bioaerosols Using Anion Exchange Resin

This protocol demonstrates a customized bioaerosol sampling method for viruses. In this system, anion exchange resin is coupled with liquid impingement-based air sampling devices for efficacious concentration of negatively-charged viruses from bioaerosols. Thus, the resin serves as an additional concentration step in the bioaerosol sampling workflow. Nucleic acid extraction of the viral particles is then performed directly from the anion exchange resin, with the resulting sample suitable for molecular analyses. Further, this protocol describes a custom-built bioaerosol chamber capable of generating virus-laden bioaerosols under a variety of environmental conditions and allowing for continuous monitoring of environmental variables such as temperature, humidity, wind speed, and aerosol mass concentration. The main advantage of using this protocol is increased sensitivity of viral detection, as assessed via direct comparison to an unmodified conventional liquid impinger. Other advantages include the potential to concentrate diverse negatively-charged viruses, the low cost of anion exchange resin (~$0.14 per sample), and ease of use. Disadvantages include the inability of this protocol to assess infectivity of resin-adsorbed viral particles, and potentially the need for the optimization of the liquid sampling buffer used within the impinger.

An anion exchange resin-based method, adapted to liquid impingement-based bioaerosol sampling of viruses is demonstrated. When coupled with downstream molecular detection, the method allows for facile and sensitive detection of viruses from bioaerosols.