Classification of Nutrients

Deepali Tewari Pandey

GBPUAT

 

There are different basis of classification of essential nutrients:

1. Quantity of nutrient required
2. Mobility of  nutrient  in soil
3. Mobility of  nutrient with in plant
4. Functions in plant

Classification on the basis of quantity of nutrient required:

1. Basic nutrients:

These constitute 96% of total dry matter of plant.

Name of Basic nutrients:

• Carbon
• Hydrogen
• Oxygen

Among these, carbon and oxygen constitute 45% each and hydrogen is 6%.

2. Macro nutrients

The nutrients which are required by plants in large quantities are called macro or major nutrients. These are nine in number.

Name of Macro nutrients:

• Nitrogen,
• Phosphorus,
• Potassium,
• Calcium,
• Magnesium,
• Sulphur,
• Carbon,
• Hydrogen and
• Oxygen.

Macro nutrients have again two categories:

Primary nutrients

Among macro nutrients, Nitrogen, Phosphorus and Potassium are known as primary nutrients which are required in a proper ratio for a successful crop.

 

Secondary nutrients

Next to primary nutrients, there are three elements such as Calcium, Magnesium and Sulphur which are known as secondary nutrients.

 

3. Micro nutrients

These nutrients required by plants in small quantities and also known as minor or trace elements. These are eight in number

Name of Micro nutrients:

• Manganese,
• Iron,
• Zinc,
• Copper,
• Boron,
• Molybdenum
• Chlorine and
• Cobalt.

 

Classification on the basis of mobility of nutrient in the soil:

Mobile nutrients:

The nutrients are highly soluble and these are not adsorbed on clay complexes.

Example: NO₃^-, SO₄^2-,BO₃^2-, Cl^- and Mn+²

Less mobile nutrients:

They are soluble, but they are adsorbed on clay complex, so their mobility is reduced.

Example: NH₄⁺, K⁺, Ca⁺, Mg²⁺, Cu2⁺

Immobile nutrients:

Nutrient ions are highly reactive and get fixed in the soil.

Example: H₂PO₄^-,HPO₄^2-, Zn²⁺

 

Classification on the basis of mobility with in plant:

Highly mobile:             N, P and K.

Moderately mobile:     Zn

Less mobile:                S, Fe, Mn, Cl, Mo and Cu

Immobile:                     Ca and B

 

Classification on the basis of functions in the plant:

1. Elements that provide basic structure to plant

Example:  Carbon, Hydrogen and Oxygen

1. Elements useful in energy storage, transfer and bonding: These are accessory structural elements which are more active and vital for living tissues.

Example: N, S and P.

1. Elements necessary for charge balance.

Example: K, Ca and Mg.

1. Elements involved in enzyme activation and electron transfer.

Example: Fe, Mn, Zn, Cu, B, Mo and Cl.

 

 Beneficial nutrients: These are not included in essential nutrients, but their application increases the yield up to some extent.

Example: Sodium, Silicon, and Vanadium.