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The Soil, Water and Forage Analytical Laboratory (SWFAL) was established by the Oklahoma Cooperative Extension Service to provide soil testing, plant, animal waste and water analyses for the State of Oklahoma and anyone who needs agricultural testing services. Each year over 60,000 various samples are submitted for analyses by thousands of farmers, ranchers, homeowners, consultants, governmental agencies and researchers. Interpretations and recommendations are made based on many years' field calibrations conducted in Oklahoma. SWFAL provides valuable information that helps lab users to protect and utilize their soil, water, animal manure, and forage resources efficiently and effectively.

Benefits of Testing


Soil Testing: The Best Management Practice

  • Increases productivity by identifying soil nutrients or soil chemical factors that are limiting plant growth;
  • Increases fertilizer use efficiency by indicating appropriate rates for different soils and crops;
  • Protects the environment by preventing over fertilization;
  • Identifies polluted or contaminated soils.


Water Testing

  •  Protects the health of people, livestock, fish and crops;
  • Identifies polluted or contaminated water supplies.


Forage and Feed Testing

  • Aids in identification of best management practices for forage production;
  • Improves marketability of the forage;
  • Increases livestock feeding efficiency;
  • Prevents livestock poisoning from nitrate.


Manure and Animal Waste Testing

  • Use nutrients efficiently by knowing the content of various types of manure;
  • Provide information for Nutrient Management Plan development and water quality protection;
  • Ensure waste treatment facility functioning properly.


Greenhouse Media Testing

  • Ensure adequate and balanced nutrients;
  • Maintaining appropriate pH;
  • Avoid high salinity and other toxic elements building up in the media.

General Lab Information


Turn Around Time

Samples for routine analysis are normally analyzed and reported within 2 to 5 working days after they are received. Forage nitrate results are reported the next day. All results are available for downloading from the internet with user name and password.


Submitting Samples

Samples should be submitted through County Extension Offices or directly to the lab. County Extension Offices throughout the state provide sample bags/water bottles, tools and technical assistance for collecting and shipping samples, and result interpretation.  Click here for more information.



Results of all tests are available only to the client, unless released by client's written notification.



SWFAL employs state-of-the-art equipment capable of handling a wide range of analytical tasks. The main instruments used in the lab include:

  1. Two Lachat Flow Injection Auto-analyzers
  2. Two Spectro ICP Spectrometers
  3. Two Ankom Fiber Analyzers
  4. Two LECO CN Combustion Analyzers and one Elementar CN Combustion Analyzer
  5. One automated pH analyzer, and one auto-titrator.


Quality Assurance

Accuracy and precision of test results are assured through daily analysis of quality control samples, a three step internal data review process, and participation in external certification and sample exchange programs. All instruments are calibrate with certified standards and maintained according to the specification.


Internal quality control standards listed below are included in each sample run. The permissible ranges are set at two times the standard deviation (mean ± 2 std.) If results are outside the permissible ranges, corrective action will be taken.

  1. One check sample is included in every 19 samples for soil pH, nitrate, phosphorus and potassium analyses;
  2. Alfalfa check standards are part of forage analyses: protein, ADF and NDF;
  3. Salinity check samples and blanks are used for soil and water salinity analyses. Anion and cation balance is also used to ensure accuracy.


External Certification or Sample Exchange Programs

  1. Agricultural Laboratory Proficiency (ALP) Program since 2006, soil, water and plant samples three times per year;
  2. Manure Analysis Proficiency Program since 2004, three times per year;
  3. National Forage Testing Association's Forage Analysis Certification Program since 1993, five times per year, certification has been granted every year since 1995.
  4. Environmental Resource Associates, water samples 4 times per year since 2006.

Need More Help

For soil testing, soil fertility, fertilizers, animal waste nutrients related questions, contact:

  • Brian Arnall - Precision Nutrient Management Extension
  • Nutrient Management/Precision Ag


Cropping Systems and Oil Seed Crop Production, contact:


For crop production, contact:

For drinking water, pond water, irrigation water, on-site waste water, contact:

  • Storm Water Extension
  • Sergio Abit - Onsite Wastewater Treatment
  • Marley Beem - Aquaculture Specialist
  • Irrigation and Water Resources


For vegetables, flowers, lawn, golf courses, fruit crops contact:

For pests related questions, contact:

  • Small Grains Weed Specialist
  • Weed Science
  • IPM, insects
  • Jen Olson - Plant Diseases


Turf and Horticultural Epidemiology

  • Ornamental/Turfgrass Pest Insects


For animal nutrition, contact:


For animal waste management, contact:


For lime, fertilizer and soil amendments rules and testing, contact:


Other laboratories in the area:


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