Soils - Part 10: The Scientific Basis for Making Fertilizer Recommendations Glossary


soil test calibration - A means of establishing a relationship between a given soil test value and the yield response from adding a nutrient to soil as fertilizer.

deficiency correction

One of three approaches to making fertilizer recommendations which is based on the concept that a nutrient should be applied only if there is a reasonable expectation of a crop response.  Under this approach, fertilizers should be applied only if they increase yields, and then only at optimum rates.

maintenance approach

One of three approaches to making fertilizer recommendations which sets soil test level goals for specific nutrients and then recommends fertilizer to build the soil to those nutrient goals.  The maintenance approach emphasizes maintaining the soil fertility level at or above the point of the economic maximum yield.


Element needed in large amounts for plant development; found naturally and in applied fertilizers.

nutrient removal

One of three approaches to making fertilizer recommendations, nutrient removal is the oldest method and was developed before reliable soil testing was readily available. Under this approach, fertilizer recommendations are based on how much nutrient a specific crop is likely to remove from the soil and how much nutrient will be needed to replace it. It does not account for soils’ ability to supply many essential nutrients.

soil test correlation

The relationship between the amount of nutrient extracted from soil by a laboratory test and nutrient uptake by plants in the greenhouse or field and/or crop yield.

soil testing

Chemical analysis of soil samples to assess soil nutrient levels and determine how fertilizer use can be improved.