Nutrient (ppm) Very Low Low Medium High Very High Best Use of Test
Phosphorus        P            
     Olsen Bicarbonate 0-3 4-9 10-16 17-30 30+ neutral, alkaline, calcareous
     Bray-1 0-5 6-12 13-25 26-50 51+ neutral, acidic
     Bray-2 * * * * * pH dependent
     Mehlich-2 0-5 6-12 13-25 26-50 51+ wide range of soils
     Mehlich-3 0-5 6-12 13-25 26-50 51+ wide range of soils
Potassium         K 0-40 41-80 81-120 121-200 201+  
Sulfate 0-4 5-7 8-11 12-15 16+ low organic matter
Magnesium       Mg 0-10 11-20 21-35 36-50 51+  
Zinc                 Zn 0-0.25 0.26-0.50 0.51-0.75 0.76-1.00 1.01+ alkaline soils
Iron                 Fe 0-1.0 1.1-2.0 2.1-4.5 4.6-10.0 10.1+ alkaline soils
Copper             Cu 0-0.10 0.11-0.20 0.21-0.30 0.31-0.60 0.61+  
Manganese        Mn 0-0.5 0.6-1.0 1.1-1.5 1.6-4.0 4.1+ alkaline soils
Boron               B 0-0.10 0.11-0.25 0.26-0.50 0.51-2.00 2.1+  
Aluminum            

KCI xchangeable

0-1 2-5 6-20 21-40 40+ for acid soils
*Predicts amount of insoluble  tricalcium phosphate
CEC ranges for different soil textures, pH<7.0
Sand   <6  
Sandy Loam   5-10  
Loam   9-18  
Clay Loam   15-25  
Clay    >22  
1:1 pH pH Rating
<5.4 Strongly acidic
5.4-5.7 Moderately acidic
5.8-6.2 Slightly acidic
6.3-7.3 Neutral
>7.3 Alkaline
Soluble Salts mmho/cm
No crop hazard 0-1.5
Yield reduction on sensitive crops 1.6-3.0
Moderate yield reduction 3.1-5.5
Severe yield reduction 5.6+

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