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Competency Area 2: Basic Concepts of Soil Fertility

PO 8. Describe the following nutrient transformations and interactions.

  1. Mineralization
  2. Immobilization
  3. Nutrient uptake antagonism

Mineralization is the conversion of a nutrient from the organic (i.e. bound to carbon and hydrogen) form to the inorganic form.  The process occurs when organic materials, such as soil organic matter, manure, plant residue, or biosolids, are decomposed by soil microorganisms.  The nutrient is released, and is available for uptake by new plants.

Immobilization is the reverse process of mineralization, wherein nutrients are converted from the inorganic to organic forms (i.e. taken by soil microbes and incorporated into their cells), making them unavailable to plants.

Nutrient uptake antagonism refers to the competition between nutrients for uptake by plants.  The two nutrients, often ions with the same charge, are said to be antagonistic with regard to the other.  Some examples include:

  • Phosphorus excess can lead to reduced zinc uptake
  • Potassium excess has been found to reduce magnesium uptake and vice versa
  • Calcium excess can cause boron or magnesium deficiencies