Agronomic Services - Soil Testing: Understand Your Report - Commercial Growers

Report Abbreviations

Ac - exchangeable acidity
B - boron
BS% - % CEC occupied by basic cations
Ca% - % CEC occupied by calcium
CEC - cation exchange capacity
Cu-I - copper index
ESP - exchangeable sodium percent
HM% - percent humic matter
K-I - potassium index
K2O - potash
Mg% - % CEC occupied by magnesium
MIN - mineral soil class
Mn - manganese
Mn-Al1 - Mn-availability index for crop 1
Mn-AI2 - Mn-availability index for crop 2
Mn-I - manganese index
M-O - mineral-organic soil class
N - nitrogen
Na - sodium
NO3-N - nitrate nitrogen
ORG - organic soil class
pH - current soil pH
P-I - phosphorus index
P2O5 - phosphate
S-I - sulfur index
SS-I - soluble salt index
W/V - weight per volume
Zn-AI - zinc availability index
Zn-I - zinc index

Sample Information

When you collected your soil samples, you should have given each sample a unique sample ID to help you remember where you collected that sample. In the example below, the first sample was given the Sample ID of 1.

Lime and Fertilizer Recommendations

Lime: If testing finds that soil pH is too low for the crop(s) indicated, a lime recommendation will be given in units of ton/acre. For best results, mix the lime into the top 6 to 8 inches of soil several months before planting. For no-till or established plantings where this is not possible, apply no more than 1 to 1.5 ton/acre at one time, even if the report recommends more. You can apply the rest in similar increments every six months until the full rate is applied. If MG is recommended and lime is needed, use dolomitic lime.

Fertilizer: Recommendations for field crops or other large areas are listed separately for each nutrient to be added (in units of lb./acre unless otherwise specified). Recommendations for N (and sometimes for B) are based on research/field studies for the crop being grown, not on soil test results.

K-I and P-I values are based on test results and should be > 50. If they are not, follow the fertilizer recommendations given.

If Mg is needed and no lime is recommended, 0-0-22 (11.5% Mg) is an excellent source; 175 to 250 lb. per acre alone or in a fertilizer blend will usually satisfy crop needs.

The soluble salt index (SS-I) levels appear only on reports for greenhouse soil or problem samples.

Commercial producers should pay special attention to micronutrient levels. If $, pH$, $pH, C or Z notations appear on the soil report, refer to $Note: Secondary Nutrients and Micronutrients.

Test Results

The first seven values [soil class, HM%, W/V, CEC, BS%, Ac and pH] describe the soil and its degree of acidity. The remaining values [P-I, K-I, Ca%, Mg%, Mn-I, Mn-AI1, Mn-AI2, Zn-I, Zn-AI, Cu-I, S-I, SS-I, Na, ESP, SS-I, NO3-N (not routinely available)] indicate levels of plant nutrients or other fertility measurements.

More Information

Additional information can be found by clicking on the links provided. In the example below, there are links to Soil Fertility Note 3 and Soil Fertility Note $.