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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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. <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. 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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.

<table><tbody><tr><td>5.9 ml soda glass flat bottom 55 x 15.5 mm</td><td>Labco Limited</td><td>719W</td><td>Collection vials</td></tr><tr><td>16.5 mm screw caps with pierceable rubber septum</td><td>Labco Limited</td><td>VC309</td><td>Caps for&amp;nbsp; vials</td></tr><tr><td>90-well plastic vial rack, 17.1 mm well I.D.</td><td>Wheaton</td><td>868810</td><td>Rack for organizing vials</td></tr><tr><td>Regular bevel needles 23 G x 1&quot;</td><td>BD</td><td>305193</td><td>Needles for sample collection</td></tr><tr><td>Stopcocks with luer connections, 1-way, male slip</td><td>Cole-Parmer</td><td>EW-30600-01</td><td>Stopcocks for syringes</td></tr><tr><td>30 ml syringe, slip tip</td><td>BD</td><td>309651</td><td>Syringes for sample collection</td></tr><tr><td>Stopwatch or timer</td><td>Various</td><td>N/A</td><td>For timing field sampling</td></tr><tr><td>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>Various</td><td>N/A</td><td>Chamber anchor and lid - bottom cut out of anchor, holes for septum and vent tubing bored in lid</td></tr><tr><td>Gray butyl stoppers 20 mm</td><td>Wheaton</td><td>W224100-173</td><td>Chamber septa for syringe sampling - insert into hole bored in lid top</td></tr><tr><td>Tygon tubing 4.0 mm I.D. x 5.6 mm O.D.</td><td>Sigma-Aldrich</td><td>Z685623</td><td>Chamber vent tubing - insert in hole bored in lid side, flush with exterior, approximately 25 cm coiled in lid interior (a 1 ml syringe tip may be used as an attachment mechanism)</td></tr><tr><td>Adhesive foam rubber tape or HDPE O-ring</td><td>Various</td><td>N/A</td><td>Chamber sealing mechanism - fastened to underside of lid rim</td></tr><tr><td>Reflective&amp;nbsp; insulation, 0.3125&quot; thickness</td><td>Lowe&#039;s</td><td>409818</td><td>Insulating and reflective coating - affix to exterior of chamber lid</td></tr><tr><td>Large metal binder clips, 2&quot; size with 1&quot; capacity, or manufactured draw latch as appropriate</td><td>Staples / McMaster</td><td>831610 (Staples) / 1863A21 (McMaster)</td><td>Lid attachment mechanism - for clamping lid to anchor during sampling</td></tr><tr><td>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>Various</td><td>N/A</td><td>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

The Use of an Automated System (GreenFeed) to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

Ruminant animals (domesticated or wild) emit methane (CH4) through enteric fermentation in their digestive tract and from decomposition of manure during storage. These processes are the major sources of greenhouse gas (GHG) emissions from animal production systems. Techniques for measuring enteric CH4 vary from direct measurements (respiration chambers, which are highly accurate, but with limited applicability) to various indirect methods (sniffers, laser technology, which are practical, but with variable accuracy). The sulfur hexafluoride (SF6)&#160;tracer gas method is commonly used to measure enteric CH4 production by animal scientists and more recently, application of an Automated Head-Chamber System (AHCS) (GreenFeed, C-Lock, Inc., Rapid City, SD), which is the focus of this experiment, has been growing. AHCS is an automated system to monitor CH4 and carbon dioxide (CO2) mass fluxes from the breath of ruminant animals. In a typical AHCS operation, small quantities of baiting feed are dispensed to individual animals to lure them to AHCS multiple times daily. As the animal visits AHCS, a fan system pulls air past the animal&#8217;s muzzle into an intake manifold, and through an air collection pipe where continuous airflow rates are measured. A sub-sample of air is pumped out of the pipe into non-dispersive infra-red sensors for continuous measurement of CH4 and CO2 concentrations. Field comparisons of AHCS to respiration chambers or SF6 have demonstrated that AHCS produces repeatable and accurate CH4 emission results, provided that animal visits to AHCS are sufficient so emission estimates are representative of the diurnal rhythm of rumen gas production. Here, we demonstrate the use of AHCS to measure CO2 and CH4 fluxes from dairy cows given a control diet or a diet supplemented with technical-grade cashew nut shell liquid.

The Use of an Automated System GreenFeed to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

Accuracy and precision of the techniques used to measure methane emissions from ruminant animals are critically important for the success of greenhouse gas mitigation efforts. This manuscript describes the principles and operation of an automated system to monitor methane and carbon dioxide mass fluxes from the breath of ruminant animals.

השימוש במערכת אוטומטית (GreenFeed) לפקח פליטות המעיים מתאן ופחמן דו חמצני מבעלי חיים מעלה הגירה

Ruminant animals (domesticated or wild) emit methane (CH4) through enteric fermentation in their digestive tract and from decomposition of manure during ...

A CO2 Concentration Gradient Facility for Testing CO2 Enrichment and Soil Effects on Grassland Ecosystem Function

Continuing increases in atmospheric carbon dioxide concentrations (CA) mandate techniques for examining impacts on terrestrial ecosystems. Most experiments examine only two or a few levels of CA concentration and a single soil type, but if CA can be varied as a gradient from subambient to superambient concentrations on multiple soils, we can discern whether past ecosystem responses may continue linearly in the future and whether responses may vary across the landscape. The Lysimeter Carbon Dioxide Gradient Facility applies a 250 to 500 &#181;l L-1 CA gradient to Blackland prairie plant communities established on lysimeters containing clay, silty clay, and sandy soils. The gradient is created as photosynthesis by vegetation enclosed in in temperature-controlled chambers progressively depletes carbon dioxide from air flowing directionally through the chambers. Maintaining proper air flow rate, adequate photosynthetic capacity, and temperature control are critical to overcome the main limitations of the system, which are declining photosynthetic rates and increased water stress during summer. The facility is an economical alternative to other techniques of CA enrichment, successfully discerns the shape of ecosystem responses to subambient to superambient CA enrichment, and can be adapted to test for interactions of carbon dioxide with other greenhouse gases such as methane or ozone.

A CO2 Concentration Gradient Facility for Testing CO2 Enrichment and Soil Effects on Grassland Ecosystem Function

The Lysimeter Carbon Dioxide Gradient Facility creates a 250 to 500 &#181;l L-1 linear carbon dioxide gradient in temperature-controlled chambers housing grassland plant communities on clay, silty clay, and sandy soil monoliths. The facility is used to determine how past and future carbon dioxide levels affect grassland carbon cycling.

CO<sub&gt; 2</sub&gt; מתקן מפל ריכוזים לבדיקה CO<sub&gt; 2</sub&gt; העשרה וקרקע השפעות על תפקוד המערכת האקולוגית גראסלאנד

Continuing increases in atmospheric carbon dioxide concentrations (CA) mandate techniques for examining impacts on terrestrial ecosystems. Most ...

Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses

A method is described which uses the absence of radiocarbon in industrial chemicals and fuels made from petroleum feedstocks which frequently contaminate the environment. This radiocarbon signal &#8212; or rather the absence of signal &#8212; is evenly distributed throughout a contaminant source pool (unlike an added tracer) and is not impacted by biological, chemical or physical processes (e.g., the 14C radioactive decay rate is immutable). If the fossil-derived contaminant is fully degraded to CO2, a harmless end-product, that CO2 will contain no radiocarbon. CO2 derived from natural organic matter (NOM) degradation will reflect the NOM radiocarbon content (usually &#60;30,000 years old). Given a known radiocarbon content for NOM (a site background), a two end-member mixing model can be used to determine the CO2 derived from a fossil source in a given soil gas or groundwater sample. Coupling the percent CO2 derived from the contaminant with the CO2 respiration rate provides an estimate for the total amount of contaminant degraded per unit time. Finally, determining a zone of influence (ZOI) representing the volume from which site CO2 is collected allows determining the contaminant degradation per unit time and volume. Along with estimates for total contaminant mass, this can ultimately be used to calculate time-to-remediate or otherwise used by site managers for decision-making.

Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses

A protocol is described wherein CO2 mineralized from organic contaminant (derived from petroleum feedstocks) biodegradation is trapped, quantified, and analyzed for 14C content. A model is developed to determine CO2 capture zone's spatial extent. Spatial and temporal measurements allow integrating contaminant mineralization rates for predicting remediation extent and time.

פחמן מבוסס מדידת מינרליזציה מזהם שימוש המשולב CO<sub&gt; 2</sub&gt; ניתוח שטף ו פחמן רדיואקטיבי

A method is described which uses the absence of radiocarbon in industrial chemicals and fuels made from petroleum feedstocks which frequently contaminate ...

Calibrated Passive Sampling - Multi-plot Field Measurements of NH3 Emissions with a Combination of Dynamic Tube Method and Passive Samplers

Agricultural ammonia (NH3) emissions (90% of total EU emissions) are responsible for about 45% airborne eutrophication, 31% soil acidification and 12% fine dust formation within the EU15. But NH3 emissions also mean a considerable loss of nutrients. Many studies on NH3 emission from organic and mineral fertilizer application have been performed in recent decades. Nevertheless, research related to NH3 emissions after application fertilizers is still limited in particular with respect to relationships to emissions, fertilizer type, site conditions and crop growth. Due to the variable response of crops to treatments, effects can only be validated in experimental designs including field replication for statistical testing. The dominating ammonia loss methods yielding quantitative emissions require large field areas, expensive equipment or current supply, which restricts their application in replicated field trials. This protocol describes a new methodology for the measurement of NH3 emissions on many plots linking a simple semi-quantitative measuring method used in all plots, with a quantitative method by simultaneous measurements using both methods on selected plots. As a semi-quantitative measurement method passive samplers are used. The second method is a dynamic chamber method (Dynamic Tube Method) to obtain a transfer quotient, which converts the semi-quantitative losses of the passive sampler to quantitative losses (kg nitrogen ha-1). The principle underlying this approach is that passive samplers placed in a homogeneous experimental field have the same NH3 absorption behavior under identical environmental conditions. Therefore, a transfer co-efficient obtained from single passive samplers can be used to scale the values of all passive samplers used in the same field trial. The method proved valid under a wide range of experimental conditions and is recommended to be used under conditions with bare soil or small canopies (&#60;0.3 m). Results obtained from experiments with taller plants should be treated more carefully.

Calibrated Passive Sampling - Multi-plot Field Measurements of NH3 Emissions with a Combination of Dynamic Tube Method and Passive Samplers

Ammonia emissions are a major threat to the environment by eutrophication, soil acidification and fine particle formation and stem mainly from agricultural sources. This method allows ammonia loss measurements in replicated field trials enabling statistical analysis of emissions and of relationships between crop development and emissions.

מכויל דגימה פסיבית - מדידות שדה רבה-עלילה של NH<sub&gt; 3</sub&gt; פליטות עם שילוב של שיטת Tube הדינמית דוגמים פסיביים

Agricultural ammonia (NH3) emissions (90% of total EU emissions) are responsible for about 45% airborne eutrophication, 31% soil acidification and 12% ...

Production and Measurement of Organic Particulate Matter in the Harvard Environmental Chamber

The production and the evolution of atmospheric organic particulate matter (PM) are insufficiently understood for accurate simulations of atmospheric chemistry and climate. The complex production mechanisms and reaction pathways make this a challenging research topic. To address these issues, an environmental chamber, providing enough residence time and close-to-ambient concentrations of precursors for secondary organic materials, is needed. The Harvard Environmental Chamber (HEC) was built to serve this need, simulating the production of gas and particle phase species from volatile organic compounds (VOCs). The HEC has a volume of 4.7 m3 and a mean residence time of 3.4 h under typical operating conditions. It is operated as a completely mixed flow reactor (CMFR), providing the possibility of indefinite steady-state operation across days for sample collection and data analysis. The operation procedures are described in detail in this article. Several types of instrumentation are used to characterize the produced gas and particles. A High-Resolution Time-of-Fight Aerosol Mass Spectrometer (HR-ToF-AMS) is used to characterize particles. A Proton-Transfer-Reaction Mass Spectrometer (PTR-MS) is used for gaseous analysis. Example results are presented to show the use of the environmental chamber in a wide variety of applications related to the physicochemical properties and reaction mechanisms of organic atmospheric particulate matter.

This paper describes operation procedures for the Harvard Environmental Chamber (HEC) and related instrumentation for measuring gaseous and particle species. The environmental chamber is used to produce and study secondary organic species produced from the organic precursors, especially related to atmospheric organic particulate matter.

ייצור, מדידה של חלקיקים אורגניים בבית הבליעה סביבתיים הרווארד

The production and the evolution of atmospheric organic particulate matter (PM) are insufficiently understood for accurate simulations of atmospheric ...

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 ...

Lab-Scale Model to Evaluate Odor and Gas Concentrations Emitted by Deep Bedded Pack Manure

A lab-scaled simulated bedded pack model was developed to study air quality and nutrient composition of deep-bedded packs used in cattle mono-slope facilities. This protocol has been used to effectively evaluate many different bedding materials, environmental variables (temperature, humidity), and potential mitigation treatments that can improve air quality in commercial deep-bedded mono-slope facilities. The model is dynamic and allows researchers to easily collect many chemical and physical measurements from the bedded pack. Weekly measurements, collected over the course of six to seven weeks, allows sufficient time to see changes in air quality measurements over time as the bedded pack matures. The data collected from the simulated bedded packs is within the range of concentrations previously measured in commercial deep-bedded mono-slope facilities. Past studies have demonstrated that 8 - 10 experimental units per treatment are sufficient to detect statistical differences among the simulated bedded packs. The bedded packs are easy to maintain, requiring less than 10 minutes of labor per bedded packs per week to add urine, feces, and bedding. Sample collection using the gas sampling system requires 20 - 30 minutes per bedded pack, depending on the measurements that are being collected. The use of lab-scaled bedded packs allows the researcher to control variables such as temperature, humidity, and bedding source that are difficult or impossible to control in a research or commercial facility. While not a perfect simulation of &#34;real-world&#34; conditions, the simulated bedded packs serve as a good model for researchers to use to examine treatment differences among bedded packs. Several lab-scale studies can be conducted to eliminate possible treatments before trying them in a research or commercial-sized facility.

A protocol has been developed to measure gases, odors, and nutrient composition in lab-scaled bedded manure packs, which can be used to study ways to improve air quality in commercial cattle facilities using deep-bedded manure packs.

המעבדה-מודל להערכת ריח וריכוזי גזים הנפלטת עמוק עם מיטות Pack זבל

A lab-scaled simulated bedded pack model was developed to study air quality and nutrient composition of deep-bedded packs used in cattle mono-slope ...

Measurements of CO2 Fluxes at Non-Ideal Eddy Covariance Sites

This protocol is an example of utilizing the eddy covariance (EC) technique to investigate spatially and temporally averaged net CO2 fluxes (net ecosystem production, NEP), in non-typical ecosystems, on a currently reforested windthrow area in Poland. After a tornado event, a relatively narrow &#8220;corridor&#8221; was created within surviving forest stands, which complicates such kind of experiments. The application of other measuring techniques, such as the chamber method, is even more difficult under these circumstances, because especially at the beginning, fallen trees and in general great heterogeneity of the site provide a challenging platform to perform flux measurements and then to properly upscale obtained results. In comparison with standard EC measurements carried out in untouched forests, the case of windthrow areas requires special consideration when it comes to the site location and data analysis in order to ensure their representativeness. Therefore, here we present a protocol of real-time, continuous CO2 flux measurements at a dynamically changing, non-ideal EC site, which includes (1) site location and instrumentation setup, (2) flux computation, (3) rigorous data filtering and quality control, and (4) gap filling and net fluxes partitioning into CO2 respiration and absorption. The main advantage of the described methodology is that it provides a detailed description of the experimental setup and measurement performance from scratch, which can be applied to other spatially limited ecosystems. It can also be viewed as a list of recommendations on how to deal with unconventional site operation, providing a description for non-specialists. Obtained quality-checked, gap filled, half-hour values of net CO2, as well as absorption and respiration fluxes, can be finally aggregated into daily, monthly, seasonal or annual totals.

Measurements of CO2 Fluxes at Non-Ideal Eddy Covariance Sites

The presented protocol uses the eddy covariance method at non-typical locations, applicable to all types of short-canopy ecosystems with limited area, on a currently reforested windthrow site in Poland. Details of measuring site setup rules, flux calculations and quality control, and final result analysis, are described.

מדידות של CO2 פלוסים באתרים לא אידיאליים של אדי השונות המשותפת

This protocol is an example of utilizing the eddy covariance (EC) technique to investigate spatially and temporally averaged net CO2 fluxes (net ecosystem ...

Measurements of Soil Carbon by Neutron-Gamma Analysis in Static and Scanning Modes

The herein described application of the inelastic neutron scattering (INS) method for soil carbon analysis is based on the registration and analysis of gamma rays created when neutrons interact with soil elements. The main parts of the INS system are a pulsed neutron generator, NaI(Tl) gamma detectors, split electronics to separate gamma spectra due to INS and thermo-neutron capture (TNC) processes, and software for gamma spectra acquisition and data processing. This method has several advantages over other methods in that it is a non-destructive in situ method that measures the average carbon content in large soil volumes, is negligibly impacted by local sharp changes in soil carbon, and can be used in stationary or scanning modes. The result of the INS method is the carbon content from a site with a footprint of ~2.5 - 3 m2 in the stationary regime, or the average carbon content of the traversed area in the scanning regime. The measurement range of the current INS system is &#62;1.5 carbon weight % (standard deviation &#177; 0.3 w%) in the upper 10 cm soil layer for a 1 hmeasurement.

Here, we present the protocol for in situ measurement of soil carbon using the neutron-gamma technique for single point measurements (static mode) or field averages (scanning mode). We also describe system construction and elaborate data treatment procedures.

מדידות של פחמן בקרקע על ידי ניתוח ניוטרון-גמא חשמל סטטי וסריקה מצבי

The herein described application of the inelastic neutron scattering (INS) method for soil carbon analysis is based on the registration and analysis of ...

Engineering

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.

הדמיית טמפרטורה בניסוי דגירה בקרקע

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

מדידה של שטף גזי חממה מקרקעות חקלאיות באמצעות לשכות סטטי

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השימוש במערכת אוטומטית (GreenFeed) לפקח פליטות המעיים מתאן ופחמן דו חמצני מבעלי חיים מעלה הגירה

CO

פחמן מבוסס מדידת מינרליזציה מזהם שימוש המשולב CO

מכויל דגימה פסיבית - מדידות שדה רבה-עלילה של NH

ייצור, מדידה של חלקיקים אורגניים בבית הבליעה סביבתיים הרווארד

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

המעבדה-מודל להערכת ריח וריכוזי גזים הנפלטת עמוק עם מיטות Pack זבל

מדידות של CO₂ פלוסים באתרים לא אידיאליים של אדי השונות המשותפת

מדידות של פחמן בקרקע על ידי ניתוח ניוטרון-גמא חשמל סטטי וסריקה מצבי

הדמיית טמפרטורה בניסוי דגירה בקרקע