Fertilizer Nutrient Availability Of N, P, K
Jun 03, 2016

Nitrogen (N) :

Main Function : Component of plant proteins, chlorophyll, nucleic acids

Approx. Conc. in Plant : 1 to 6%

  • Nitrate Nitrogen (NO 3 - ) and Ammonical Nitrogen (NH 4 +) taken up by plant roots

  • Nitrate Nitrogen (NO 3 - ) mobile in the soil - Leaches readily

  • Ammonical Nitrogen (NH 4 +) held to soil cation exchange

  • Most Nitrogen (N) is in organic forms - Undergoes many transformations

Nitrogen (N) Deficiency of Plant :

 

 

Phosphorus (P) :

Main Function : Energy transfer ; metabolism, nucleic acids, nucleoproteins

Approx. Conc. in Plant : 0.05 to 1%

  • Is taken up by plant roots as  hydrogen phosphate (H 2 PO 4 - or HPO 4 2- )

  • Generally not mobile in soil - Except under conditions of high soil test levels

  • Plants get Phosphorus (P) by root interception

  • Most available at 5.5 < pH < 7.2

  • Cycles between organic and inorganic forms

Phosphorus (P) Deficiency of Plant :

 

Potassium (K) :

Main Function : Protein synthesis; translocation of carbohydrates; enzyme activation

Approx. Conc. in Plant : 0.3 to 6%

  • Moderately mobile in the soil

  • Plants obtain Potassium (K) mainly by diffusion

  • Is held on the cation exchange - Greater CEC results in greater availability

  • Natively Potassium (K) comes from soil minerals - Natively Potassium (K) comes from soil minerals and Added Potassium (K) can be fixed in these minerals

Potassium (K) Deficiency of Plant :