Question

What do you mean by nutrient immobilization?

Answer 1

Nutrient immobilization is a process that is opposite to the process of mineralization. Both of these processes are usually carried out by microbes. Substances are removed from the soil and incorporated within the microbial cells.

Complete answer:
Nutrient immobilization is the process in which elements in inorganic form are converted to organic form by microorganisms. These nutrients then become unavailable to the plants for their usage.

Additional Information:
Nitrogen is a plant macronutrient and is therefore needed by plants in larger amounts.
The fate of nitrogen depends on the C: N ratio of plant residue. If the carbon to nitrogen ratio is high then immobilization of nitrogen takes place and this is referred to as the priming effect.
The opposite happens when C: N ratio is low.
Nitrogen immobilization occurs by two main processes:
-Nitrogen gets accumulated in the microbial biomass.
-Nitrogen gets accumulated in the by-products of microbial activity.
The major functions of nitrogen in plants are:
-It helps in protein and enzyme synthesis.
-Cytochrome formation also requires nitrogen
-Other components such as ATP, coenzymes, nucleotides, vitamins, plant growth regulators, etc also require nitrogen.

Note: If nitrogen is made unavailable to plants for usage due to nutrient immobilization several deficiency diseases can arise. Some of them are:
-Chlorosis of older leaves.
-Stunted growth.
-Premature falling of leaves.
-The purple coloration of the stem.
-Reduction in yield and delayed flowering.