Fayetteville Agricultural Diagnostic Analytical Laboratory

The Fayetteville Agricultural Diagnostic Laboratory is part of the University of Arkansas System Division of Agriculture and is located at the Arkansas Agricultural Research and Extension Center (AAREC) in Fayetteville, Arkansas.  The laboratory provides routine and non-routine analytical, fee-based services related to manure, plant, soil, and solution analyses. The fee-based analysis services are available to research scientists, consultants, farmers, and the public.

The analytical services offered by the Fayetteville Agricultural Diagnostic Laboratory can be found in the menu by sample type.  The available instrumentation and literature references for the standard methods of analysis are listed in the Analytical Methods and References section. In addition to the listed analytical methods, other tests can be performed upon special request.

 

Other Available Services

The laboratory also offers growth media analysis (see form AGRI-430), sample preparation (e.g., grinding) and analytical services for samples that have been digested or extracted and need to be analyzed. Prices for most of these services are included in AGRI-421.  If the specific service of interest is not listed, please inquire via email or phone regarding availability and pricing. Clients seeking water analysis should contact the Water Resources Laboratory (1371 W. Altheimer Drive, DTAS Room 133; 479-502-9843, awrcwql@uark.edu).

 

Mission

The mission of the Fayetteville Agricultural Diagnostic Laboratory is to provide analytical services, instrumentation, and expertise for standard and specialized methods of analysis that supports agricultural and environmental research and nutrient stewardship; support student education and train future agricultural scientists. The laboratory provides instrumentation, analytical support and testing services for the University of Arkansas System Division of Agriculture programs including but not limited to plant tissue, feed and forage, animal waste and non-routine analyses for samples submitted by farmers, consultants, homeowners, industry, and scientists.   

 

Lab Hours

Monday through Friday 8:00 am to 4:30 pm

 

Contact Us

Phone (479-575-3908)
Fax (479-575-3975)
Email (agrilab@uark.edu)

 

Forms and Prices

Analytical prices and forms for the standard procedures can be found in the pdf fillable forms located below.  Additional information on specific samples types can be accessed from the menu. Please contact the lab for pricing and availability of analytical procedures not listed on the forms. The analytical procedures used in sample preparation and analysis are listed on the Analytical Methods & References page.

 FORMS

  

Forage Analysis

Forage samples are analyzed for nutrient content and feed quality on more than 1000 client-submitted samples annually. The Fayetteville Agricultural Diagnostic Laboratory participates in the Forage Proficiency Testing Program administered by the National Forage Testing Association as part of our quality assurance and quality control program. Proficiency results are available upon request.

The available forage analyses and fees are listed below and on the forage sample submission form (AGRI-412). A forage analysis report can be viewed using this link (Example Report).  The analytical information and references for the offered forage analyses can be found on the Analytical Methods page.  A searchable database is available to estimate the range of forage quality traits from prior forage analytical results.

Detailed instructions for proper forage sampling methods can be found in FSA-3114. Note the following information for submitting samples.

  • A representative sample of forage equal to a one pint volume placed in a quart-sized bag is all that is needed for analysis. Submission of larger samples increases shipping costs, which are paid for the client.
  • If more than one sample will be submitted please submit in clearly labeled bags
  • Complete all information on the sample analysis form for each sample
  • Include a check for the proper amount with the sample and completed form(s).
  • Samples may be delivered to the nearest county Extension office, shipped directly to the lab by the client, or delivered directly to the laboratory.
  • Samples reports will be retuned via email (if email address is provided) or mailed.
  • Consult MP-391 for assistance in interpretation of selected forage quality and animal nutrition information.

Typical forage analysis includes:

  • Moisture Content
  • %Crude Protein
  • ADF
  • NDF
  • TDN
  • NEL
  • Nitrate-N concentration
  • Forage Mineral Nutrient Concentration (P, K, Ca, Mg, Na, S, Fe, Mn, Zn, and Cu)
  • Silage pH
  • Forage Analysis Example

 

Soil Analysis

The Fayetteville Agricultural Diagnostic Laboratory performs fee-based, agronomic and environmental analytical services on soil samples primarily for researchers. Arkansas residents wanting free routine soil analysis and/or fertilizer recommendations should submit samples through their local county Extension Office (find your local county office) for analysis at the Marianna Soil Test Laboratory (Marianna lab).

The soil properties most frequently performed by the Fayetteville Agricultural Diagnostic Laboratory are included in the list below and prices are provided in AGRI-421. Form AGRI-423 should be used to submit soil samples for diagnosing plant growth problems that may be caused by nutrient deficiency or toxicity. The laboratory participates in the ALP proficiency program as part of our quality assurance and quality control program. Proficiency results are available upon request. 

  • Soil pH (usually 1:2 soil:water ratio, but other methods available)
  • Soil electrical conductivity (usually 1:2 soil:water ratio, but other methods available)
  • Mehlich-3 extraction
  • Total recoverable metals by EPA 3050B
  • Soil organic matter by loss on ignition
  • Total soil carbon and nitrogen
  • Soil inorganic nitrogen (nitrate- and ammonium-nitrogen)
  • Soil texture by hydrometer
  • Water-soluble chloride

 

Plant Analysis

The Fayetteville Agricultural Diagnostic Laboratory performs fee-based, analytical services on plant samples primarily for researchers and troubleshooting plant growth problems, but also for some nutrient monitoring programs (e.g., Strawberry Nutrient Monitoring).

The plant analysis tests most frequently performed by the Fayetteville Agricultural Diagnostic Laboratory are included in the list below and prices are provided in AGRI-423. Form AGRI-423 should be used to submit plant samples for diagnosing plant growth problems that may be caused by nutrient deficiency or toxicity. Clients interested in this service should complete form AGRI-423 with information regarding the plant traits, describe the problem, and the select the desired analyses. The laboratory participates in the ALP proficiency program as part of our quality assurance and quality control program. Proficiency results are available upon request. 

  • Total mineral (P, K, Ca, Mg, S, Na, Fe, Mn, Cu, Zn and B) analysis by digestion
  • Total nitrogen and carbon by combustion
  • Plant nitrate-nitrogen
  • Corn-stalk nitrate test
  • Water-soluble chloride
  • Strawberry monitoring program

Collecting the proper plant tissue sample and providing accurate information about plant symptoms is important for proper diagnosis of nutrient related maladies.  

  • Complete all information on the sample analysis form for each sample
  • Include a check for the proper amount with the sample and completed form(s).
  • Samples may be delivered to the nearest county Extension office, shipped by the client, or delivered directly to the laboratory.
  • Remove roots from the plant. Diagnostic analysis is performed only on aboveground tissue.
  • Collecting the proper tissue is critical. The proper tissue to collect varies among plant species, size, and plant age. If in doubt, collect and submit the same tissues from both healthy and sick plants for comparison. Contact the lab or your local county Extension agent with questions about sampling protocol.
  • If plant samples will be mailed, place each sample in separate labeled paper bags.
  • Soil analysis is often helpful in interpreting plant tissue analysis and diagnosing growth problems.

Analysis of strawberry petioles is performed in cooperation with the Cooperative Extension Service for the Strawberry Monitoring Program.  Instructions on participating in the Strawberry Monitoring Program are included in the enrollment form. 

Example Strawberry Monitoring Program Report

 

Manure Analysis

The Fayetteville Agricultural Diagnostic Laboratory performs fee-based, analytical services on more than 1000 dry and liquid manure samples annually for researchers and farmers to determine manure nutrient content as an aid for nutrient management. The laboratory participates in the  Manure Analysis Proficiency (MAP) program  administered by the Minnesota Department of Agriculture as part of our quality assurance and quality control program. Proficiency results are available upon request. 

The manure analysis tests most frequently performed by the Fayetteville Agricultural Diagnostic Laboratory are included in the list below and prices are provided in AGRI-429.  The analytical report provided to growers includes the analytical information and the equivalent nutrient content per moist and dry ton for N, P2O5, and K2O (Example reports for Dry and Liquid samples). The analytical information and references for the offered soil analyses can be found on the Analytical Methods page.

  • % moisture or solids
  • pH
  • Electrical conductivity
  • Primary mineral content (P, K, and Ca) analysis by digestion
  • Other mineral content (Mg, S, Na, Fe, Mn, Cu, Zn and B) analysis by digestion
  • Total nitrogen and carbon by combustion
  • Water-extractable P (WEP)
  • Inorganic nitrogen (nitrate- and ammonium-nitrogen)

 

General Laboratory Information/Resources

The available instrumentation and lab resources plus the routine methods of analysis offered by the Fayetteville Agricultural Diagnostic Laboratory is summarized below. 

  • 3500 ft2 of lab and office space plus a 500 ft2 in a head house that contains soil and plant grinding facilities.
  • Partial or complete analysis is performed on 25,000 to 30,000 samples annually
  • Equipped with multiple analytical scales and standard lab equipment (e.g., drying ovens, sample mills, pipettes, digestion blocks, shakers, etc…)
  • Precision 818 low temperature incubators (2, 17.8 ft3 units)
  • Inductively Coupled Plasma Atomic Emission Spectrophotometers:
    • Spectro Arcos-130 EOP (model Arcos HFE12)
    • Spectro Arcos 160 SOP (model FHS16)
    • Equipped with Cetac ASX520 auto-samplers
  • Cary 50 Bio UV Visible Spectrophotometer (forage and plant tissue nitrate-N analysis)
  • Elementar vario Max CN Classic Element Analyzer
  • Elementar rapid N III Analyzer
  • Spectra Star XT NIRS, Unity Scientific, NIRS
  • Skalar Analytical SanPlus Segmented Flow Analyzer
  • Bran+Luebbe AutoAnalyzer 3
  • BioTek Epoch Microplate Spectrophotomoeter
  • Ankom 200 Fiber Analyzer, Ankom Technology
  • Labconco Reflux Fiber Apparatus
  • Denver Instruments model 220, pH meter with Ag/AgCl electrode
  • Oakton 510 Series pH/Conductivity meter (for EC)
  • Dyna-Crush Soil Grinders

         

Analytical Methods and References

Soil Measurement

Literature Reference

Mehlich-3 (analysis by ICP)

Zhang, H., D.H. Hardy, R. Mylavarapu, and J. Wang. 2014. Mehlich-3. In: F.J. Sikora and K.P. Moore, editors, Soil test methods from the southeastern United States. Southern Coop. Ser. Bull. 419. Univ. of Georgia. p. 101-110. http://aesl.ces.uga.edu/sera6/PUB/MethodsManualFinalSERA6.asp

Soil pH (1:2, soil:water ratio)

Sikora, F.J., and D.E. Kissel. 2014. Soil pH. In: F.J. Sikora and K.P. Moore, editors, Soil test methods from the southeastern United States. Southern Coop. Ser. Bull. 419. Univ. of Georgia. p. 48-53. http://aesl.ces.uga.edu/sera6/PUB/MethodsManualFinalSERA6.asp

Soil EC (1:2, soil:water ratio by electrode)

Wang, J.J., T. Provin, and H. Zhang. 2014. Measurement of soil salinity and sodicity. In: F.J. Sikora and K.P. Moore, editors, Soil test methods from the southeastern United States. Southern Coop. Ser. Bull. 419. Univ. of Georgia. p. 185-193. http://aesl.ces.uga.edu/sera6/PUB/MethodsManualFinalSERA6.asp

Organic matter (weight loss on ignition)

Zhang, H., and J.J. Wang. 2014. Measurement of soil salinity and sodicity. In: F.J. Sikora and K.P. Moore, editors, Soil test methods from the southeastern United States. Southern Coop. Ser. Bull. 419. Univ. of Georgia. p. 155-157. http://aesl.ces.uga.edu/sera6/PUB/MethodsManualFinalSERA6.asp   

Soil inorganic  nitrogen (2 mol L-1 KCl extraction)

Mulvaney, R.L. 1996. Nitrogen-inorganic forms. In: D.L. Sparks, editor,

Methods of soil analysis. Part 3. SSSA Book Ser. 5. SSSA,

Madison, WI. p. 1123–1184.

Soil texture (by hydrometer)

Huluka, G. and R. Miller. 2014. Particle size determination by hydrometer method. In: F.J. Sikora and K.P. Moore, editors, Soil test methods from the southeastern United States. Southern Coop. Ser. Bull. 419. Univ. of Georgia. p. 180-184. http://aesl.ces.uga.edu/sera6/PUB/MethodsManualFinalSERA6.asp   

Total C and N (by combustion)

Provin, T. 2014Total carbon and nitrogen and organic carbon via thermal combustion analyses. In: F.J. Sikora and K.P. Moore, editors, Soil test methods from the southeastern United States. Southern Coop. Ser. Bull. 419. Univ. of Georgia. p. 149-154. http://aesl.ces.uga.edu/sera6/PUB/MethodsManualFinalSERA6.asp   

Soil chloride

(10 g soil + 20 mL DI water, shake for 20 min, centrifuge, & filter)

Cotlove, E., H.V. Trantham, and R.L. Bowman. 1958. An instrument and method for automatic, rapid, accurate, and sensitive titration of chloride in biologic samples. J. Laboratory Clinical Medicine 51(3):461-468 .

 

Wheal, M., and L. Palmer. 2010. Chloride analysis of botanical samples by ICP-OES. J. Anal. At. Spectrom.. 25:1946-1952. 10.1039/C0JA00059K.

Urea

Greenan, N.S., R.L. Mulvaney, and G.K. Sims. 1995. A microscale

method for colorimetric determination of urea in soil

extracts. Commun. Soil Sci. Plant Anal. 26:2519–2529.

doi:10.1080/00103629509369465

Total Recoverable metals (EPA 3050B)

U.S. EPA. 1996. Method 3050B: Acid Digestion of Sediments, Sludges, and Soils. Revision 2. Washington, DC. https://www.epa.gov/sites/production/files/2015-06/documents/epa-3050b.pdf

Total Dissolved P (by ICP)

Self-Davis, M.L., P.A. Moore, Jr., and B.C. Joern 2009. Water- or dilute salt-extractable phosphorus in soil. In: J.L. Kovar and G.M. Pierzynski, editors, Methods of Phosphorus Analysis for Soils, Sediments, Residuals, and Waters-Revised Edition. Southern Cooperative Series Bulletin No 408. p.22-24. https://sera17dotorg.files.wordpress.com/2015/02/sera-17-methods-for-p-2009.pdf

 

 

Routine soil grinding

Dynacrush soil crusher, Custom Laboratory Equipment

 

   

 

Plant Tissue Measurement

Literature Reference

Sample preparation and digestion with HNO3 and H2O2 (mineral elements)

Jones, J.B., and V.W. Case. 1990. Sampling, handling, and analyzing plant tissue

samples. In: R.L. Westerman, editor, Soil testing and plant analysis. 3rd ed.

SSSA Book Ser. 3. SSSA, Madison, WI. p. 389–428.

Total C and N (by combustion)

Campbell, C.R. 1992. Determination of total nitrogen in plant tissue

by combustion. In: C.O. Plank, editor, Plant analysis reference

procedures for the southern U.S. Coop. Ser. Bull. 368. Univ. of

Georgia, Athens. p. 20–22. Available at

Tissue chloride (water-extractable by ICP)

Liu, L. 1998. Determination of chloride in plant tissue. In: Y.P. Kalra,

editor, Handbook of reference methods for plant analysis. CRC

Press, Boca Raton, FL. p. 111–113.

Tissue nitrate

Cataldo, D.A., M. Maroon, L.E. Schrader, and V.L. Youngs, 1975. Rapid colorimetric determination of nitrate in plant-tissue by nitration of salicylic-acid. Commun. Soil Sci. Plant Anal. 6:71-80. 10.1080/00103627509366547.

[Modified Cataldo method. 0.5 g sample (0.1 g for high nitrate samples) extracted in 25 mL DI water, shake 20 minutes, filtered through VWR 454 filter paper, and  colorimetric analysis through UV-Vis Spec ]

Corn stalk nitrate

Binford, G.D., A.M. Blackmer, and N.M. El-Hout. 1990. Tissue test for excess nitrogen during corn production. Agron. J. 82:124–129. 

 

Manure Measurement

Literature Reference

Manure pH

Wolf., N. 2003 Determinatoin of manure pH. In: J. Peters, editor,

Recommended methods of manure analysis. Publ. A3769. Univ. of

Wisconsin Ext, Madison. p. 50-51. http://aesl.ces.uga.edu/sera6/PUB/Recommended_Methods_Manure_Analysis_a3769.pdf

Manure EC

Wolf., N. 2003. In: J. Peters, editor, Recommended methods of manure analysis. Publ. A3769. Univ. of Wisconsin Ext, Madison. p. 48–49. http://aesl.ces.uga.edu/sera6/PUB/Recommended_Methods_Manure_Analysis_a3769.pdf

Total C and N

Watson, M., A. Wolf, and N. Wolf. 2003. Total nitrogen. In: J. Peters, editor,

Recommended methods of manure analysis. Publ. A3769. Univ. of

Wisconsin Ext, Madison. p. 18–24. http://aesl.ces.uga.edu/sera6/PUB/Recommended_Methods_Manure_Analysis_a3769.pdf

Inorganic N (by colorimetry)

Peters, J., A. Wolf, and N. Wolf. 2003. Ammonium nitrogen. In: J. Peters,

editor, Recommended methods of manure analysis. Publ. A3769. Univ. of

Wisconsin Ext, Madison. p. 25–29. http://aesl.ces.uga.edu/sera6/PUB/Recommended_Methods_Manure_Analysis_a3769.pdf

Mineral nutrient content (by HNO3 digestion)

Wolf, A., M. Watson, and N. Wolf. 2003. Digestion and dissolution methods for P, K, Ca, Mg and trace elements. In: J. Peters, editor, Recommended methods of manure analysis. Publ. A3769. Univ. of Wisconsin Ext., Madison. p. 30-38. http://aesl.ces.uga.edu/sera6/PUB/Recommended_Methods_Manure_Analysis_a3769.pdf  

Moisture content and solids

Hoskins, B., A. Wolf, and N. Wolf. 2003. Dry matter analysis. In: J. Peters, editor,

Recommended methods of manure analysis. Publ. A3769. Univ. of

Wisconsin Ext, Madison. p. 18–24. http://aesl.ces.uga.edu/sera6/PUB/Recommended_Methods_Manure_Analysis_a3769.pdf  

Water-extractable P (WEP)

Wolf, A.M., P.A. Moore, Jr., P.J.A. Kleinman, and D.M. Sullivan. 2009. Water-extractable phosphorus in animal manure and biosolids. In: J.L., Kovar and G.M. Pierzynski, editors, Methods of Phosphorus Analysis for Soils, Sediments, Residuals, and Waters-Revised Edition. Southern Cooperative Series Bulletin No 408. p.76-80. https://sera17dotorg.files.wordpress.com/2015/02/sera-17-methods-for-p-2009.pdf

Analytical Notes

Poultry Litter Sample Homogenization

Submitted samples are split into two subsamples. Using a scoop or spatula, a portion (~4 oz) of the bulk litter is transferred to a labeled (~4 oz) plastic container for storage and used for WEP and dry matter determination. The bulk (unaltered) litter subsample is refrigerated at 4°C if the WEP extraction will be performed on another day. A second subsample (~4 oz) of litter is homogenized using a coffeebean grinder and used only for determining total nutrient content of litter. 


 

Forage Measurement

Literature Reference

Dry matter determination

Shreve, B., N. Thiex, and M. Wolf. 2006. National Forage Testing Association Reference Method: Dry Matter by Oven Drying for 3 Hours at 105°

 C. NFTA Reference Methods. National Forage Testing Association, Omaha, NB, www.foragetesting.org

Mineral nutrients (digestion with HNO3 and H2O2)

Jones, J.B., and V.W. Case. 1990. Sampling, handling, and analyzing plant tissue

samples. In: R.L. Westerman, editor, Soil testing and plant analysis. 3rd ed.

SSSA Book Ser. 3. SSSA, Madison, WI. p. 389–428.

Laboratory dry matter

Goering, H.K. and P.J. Van Soest. 1970. Forage Fiber Analyses (apparatus, reagents, procedures, and some applications). ARS/USDA Handbook No. 379, Superintendent of Documents, US Government Printing Office, Washington, D.C. 20402. (Adaption for using forced-air drying ovens)

Crude Protein (Total N by combustion×6.25)

Association of Official Analytical Chemists (AOAC). 1990. Method 990.03  Protein (crude) in Animal Feed. 15th ed. Association of Official Analytical Chemists. Arlington, VA.

ADF (Acid Detergent Fiber)

Association of Official Analytical Chemists (AOAC). 1990. Method 973.18: Fiber (Acid Detergent) and Lignin in Animal Feed. 15th ed. Association of Official Analytical Chemists. Arlington, VA.

 

ANKOM Technology Method 5 – Acid Detergent Fiber in Feeds – Filter Bag Technique for A200.

NDF (Neutral Detergent Fiber)

Van Soest, P.J., J.B. Robertson, and B.,A. Lewis. 1991. Methods for dietary fiber, neutral detergent fiber, and non-starch polysaccharides in relation to animal nutrition. J. Dairy. Sci. 74:3583-3597.

 

ANKOM Technology Method 6 – Neutral Detergent Fiber in Feeds – Filter Bag Technique for A200.

ADIN (Acid Detergent Insoluble N)

ADIN % of N = (ADIN % of DM/total %N) × 100

Goering, H.K., and P.J. Van Soest. 1970. Forage Fiber analysis (apparatus, reagents, procedures, and some application). USDA Agriculture Handbook No. 379.

Goering, H.K., C.H. Gordon, R.W. Hemken, D.R. Waldo, P.J. Van Soest, and L.W. Smith. 1972. Analytical estimates of nitrogen digestibility in heat damaged forages. J. Dairy Sci. 55(9):1275-1280.

Silage pH

15 g 'as is' forage + 200 mL deionized water, stirred, and measured after 5 minutes

Forage nitrate-N

Cataldo, D.A., M. Maroon, L.E. Schrader, and V.L. Youngs, 1975. Rapid colorimetric determination of nitrate in plant-tissue by nitration of salicylic-acid. Commun. Soil Sci. Plant Anal. 6:71-80. 10.1080/00103627509366547.

[Modified Cataldo method. 0.5 g sample (0.1 g for high nitrate samples) extracted in 25 mL DI water, shake 20 minutes, filtered through VWR 454 filter paper, and  colorimetric analysis through UV-Vis Spec]

TDN (Total Digestible Nutrients)

Calculation. For details contact Dr. Shane Gadberry (sxg011@uark.edu)

NEL (Net Energy for Lactation)

Calculation:  NEL = [(TDN × 0.0245) - 0.12] × 0.454

National Research Council. 1985. Ruminant nitrogen usage. National Academies Press.

RFV (Relative Feed Value Calculation)

Calculation: RFV = DDM × DMI / 1.29

Where Digestible Dry Matter (DDM) = 88.9 - (0.779 × %ADF)

Ball, D.M., C.S. Hoveland, and G.D. Lacefield. 2002. Southern Forages, Third Ed. Potash & Phosphate Institute and the Foundation for Agronomic Research, Nawrenceville, GA.

Methods Notes

Dry Matter

For routine analysis, laboratory dry matter is determined on submitted samples before analysis and involves oven drying at 55°C overnight.

ADF/NDF

Determined using either the Labconco Reflux unit or Ankom Fiber Analyzer.

 

 

Fayetteville Agricultural Diagnostic Lab
1366 West Altheimer Drive
Fayetteville, AR 72704