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Test Procedures & Methods
 
   

Test Procedures & Methods

When comparing results from one laboratory to the next it is important to determine the following:
  1. Laboratory method used for each analysis.
  2. Units reported for each analysis.
  3. Any conversion or calculation used for specific tests.

It is important to note that there is no perfect method for determining how much or little of an essential nutrient is available for plant uptake. Availability is affected by: soil moisture, temperature, soil pH, clay/organic matter content, soil drainage, physical barriers and many other factors. As these factors change the availability of nutrients also change. What a soil test measures is the degree of fertility; be it low, medium or high.

Analysis Units Method Description


SOIL ANALYSIS

Soil pH N/A1:1 Soil/Water Slurry
Soluble Salt mmhos/cm1:1 Soil/Water Slurry
Buffer pHN/ASikora Buffer Solution
Cations
     Ca-Mg-K-Na

ppm

Ammonium Acetate Extraction
Phosphorus
     If pH < 7.2
     If pH > 7.1

ppm
ppm

Bray I Extraction
Olson Extraction
Traces
     Zn-Mn-Fe-Cu

ppm

DTPA Extraction
Sulfur
ppm
Monocalcium Phosphate (ICP Determination
Boron
ppm
Hot Water Extraction (ICP Determination
Nitrate-N ppmCadmium Reduction
Particle Size Analysis
(Sand-Slid-Clay)
%
Hydrometer Measurement
Salinity Evaluation mmhos/cmSaturated Paste Extraction
Other Methods Available  Pertains to country of origin
Extractable Soil Ammonium ppmKCI extraction 
Extractable Chloride in SoilppmCalcium Nitrate Extraction
Soil Moisture%Loss of Drying
Organic Matter%Loss of Ignition
Extractable AluminumppmCesium Chloride Extraction
Extractable MolybdenumppmAmmonium Oxolate
   


PLANT ANALYSIS

Nitrate-Nitrogen ppm 2% Acetic Acid digestion
Phosphate-Phosphorus ppm2% Acetic Acid digestion
Extractable Potassium %2% Acetic Acid digestion
Total Nitrogen% Kjeldahl Digestion
Total Phosphorus%Nitric Acid/Hydrogen Peroxide Digestion
Plant Minerals% and ppmNitric Acid/Hydrogen Peroxide Digestion
   


GREENHOUSE MEDIA TESTING

Media pH N/ASaturated Media Extract (SMS)
Electrical Conductivitymmhos/cm                     "
Phosphorus ppm                     " 
Potassium    "                     " 
Calcium    "                     " 
Magnesium   "                      " 
Sodium   "                      " 
Zinc    "                      " 
Manganese   "                      " 
Copper    "                      " 
Iron   "                      "
Boron   "                      "
Aluminum    "                      "
Nitrate-N   "                      "
Ammonium-N    "                      "
Extractable
     Zinc
     Manganese
     Copper
     Iron

ppm
  "
  "
  "

DTPA Extraction
           "
           "
           "
Organic Matter &
Organic Carbon
%

Loss on Ignition

Total Nitrogen% Kjeldahl Digestion
Soluble P205% Citric Acid Digestion
Soluble K20%Ammonium Oxalate


References us for laboratory methodologies:

  • Analytic procedures used in US EPA Report SW-846, Test Methods for Evaluating Soil Waste, 3rd Edition, November 1990, as revised.
  • Association of Official Analytical Chemists (AOAC) Official Methods of Analysis, 1990, 15th Edition.
  • Methods of Soil Analysis, Parts I, II, and III. Soil Science Society of American. 1996.
  • North Central Regional (NCR) Publication No. 221 (Revised).  Recommended Chemical Procedures for the North Central Region Bulletin No. 499 (Revised) October 1988.
  • Standard Methods for the Examination of Water and Wastewater, 18th Edition, 1992.
  • The American Society for Testing and Materials (ASTM) Standard Tests Methods, 1988.

For more information please contact:

AgSource Harris Laboratories - Lincoln, NE402-476-0300harrislabs@agsource.com


Copyright © by AgSource Harris, a Division of Cooperative Resources International

(Click to view Harris methods used)

   
 
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