METHODS USED AT WESTERN LABORATORIES FOR SOILS
Parameter Units Method-Number Methods
pH Unit S-2.20 1:1 Soil:Water Ratio

pH SMP Buffer

     

Soluble Salts

mmhos/cm 1:2 Soil:Water Ratio

Organic Matter

% S-9.10 LOI

Lime

% Fizz Effervescense 2N HCL

Nitrates – NO3

ppm = mg/kg S-3.10 Cadnium Reduction/KCL Extraction

Ammonium – NH4

ppm = mg/kg S-3.50 KCL Extraction/Exchangeable

Phosphorus – Basic Soils

ppm = mg/kg S-4.10 Bicarbonate

Phosphorus – Acid Soils

ppm = mg/kg   Bray

Potassium

ppm = mg/kg S-5.10 NH4 OAc Extractable

Calcium

ppm = mg/kg S-5.10 NH4 OAc Extractable

Magnesium

ppm = mg/kg S-5.10 NH4 OAc Extractable

Sodium

ppm = mg/kg S-5.10 NH4 OAc Extractable

Zinc

ppm = mg/kg S-6.10 DTPA Extractable

Iron

ppm = mg/kg S-6.10 DTPA Extractable

Manganese

ppm = mg/kg S-6.10 DTPA Extractable

Copper

ppm = mg/kg S-6.10 DTPA Extractable

Sulfate

ppm = mg/kg S-5.10 NH4 OAc Extractable

Boron

ppm = mg/kg S-6.10 DTPA Extractable/Sorbitol

Texture

Unit   By feel

Cation Exchange Capacity

meq = cmol/kg NH4 OAc Measured

Total Phosphorus

% P-4.10 Wet Ashing

SAR = % Na of CEC

  S-1.60 NH4 OAc


METHODS USED AT WESTERN LABORATORIES FOR PLANTS
Parameter Units Method-Number Methods

Nitrates – NO3

ppm = mg/kg S-3.10 Cadnium Reduction/NH4 OAC Extractable

Ammonium – NH4

ppm = mg/kg S-3.50 Cadnium Reduction/NH4 OAC Extractable

Phosphorus – Basic Soils

ppm = mg/kg S-4.10 Bicarbonate

Phosphorus – Acid Soils

ppm = mg/kg   Bray

Potassium

ppm = mg/kg S-5.10 Wet Ash

Calcium

ppm = mg/kg S-5.10 Wet Ash

Magnesium

ppm = mg/kg S-5.10 Wet Ash

Sodium

ppm = mg/kg S-5.10 Wet Ash

Zinc

ppm = mg/kg S-6.10 Wet Ash

Iron

ppm = mg/kg S-6.10 Wet Ash

Manganese

ppm = mg/kg S-6.10 Wet Ash

Copper

ppm = mg/kg S-6.10 Wet Ash

Sulfate

ppm = mg/kg S-5.10 Wet Ash

Boron

ppm = mg/kg S-6.10 Wet Ash