Secondary and Micronutrients

Secondary and Micronutrients

Do the terms secondary and micro imply that some nutrients are less important to plants?

Certainly not, each of the 13 nutrients is essential because each has a specific function in plant growth. The terms major, secondary and micro tell us about the quantity of a nutrient that is necessary to carry out its specific task.

Major Nutrients, and their sources

Nitrogen(N)

Nitrogen is the nutrient with the greatest influence on crop yield through the effect on chlorophyll and protein production

  • Intensifies green colour (Chlorophyll)
  • Increases leaf size
  • Increases growth rate
  • Increases final yield
  • Increases protein content

Plants deficient in nitrogen have pale green or yellow leaves because of lack of chlorophyll and become stunted through lack of leaf expansion

The most common nitrogen fertilizers are:

NP/NPK Complex Fertilizers ………………………………………………………………… (5-30% N)

Ammonium Nitrate (AN) ………………………………………………………………… (33.5-34.5% N)

Calcium Ammonium Nitrate (CAN) ………………………………………………………………… (26-28% N)

Ammonium Sulphate (AS) ………………………………………………………………… (21% N)

Calcium Nitrate (CN) ………………………………………………………………… (15.5% N)

Urea (U) ………………………………………………………………… (46%)

Urea Ammonium Nitrate Solution (UAN)………………………………………………………………… (28-32%)

Phosphorus(P)

Phosphorus is important in root development, the ripening process and particularly in the manufacture and use of sugars and complex carbohydrates. A good supply of phosphorus is important in the early stages of a plant’s life and for early maturity

  • Stimulates root development
  • Helps plants get established early in the season
  • Encourages maturity

Phosphorus helps plants produce an effective root system that absorbs water and nutrients from the soil. The application of sufficient phosphorus also results in better setting of seeds and fruits and aids in crop ripening

 

Phosphorus is commonly referred to as phosphate (P2O5).The most common phosphate fertilizer are

NP/NPK Complex Fertilizers ………………………………………………………………… (5-23.5% P2O5)

Diamond Phosphate (DAP) ………………………………………………………………… (46-53% N)

Calcium Ammonium Nitrate (CAN) ………………………………………………………………… (26-28% N)

Monoammonium Phosphate (MAP) ………………………………………………………………… (48-55% N)

Single Superphosphate (SSP) ………………………………………………………………… (16-20% N)

Triple Superphosphate (U) ………………………………………………………………… (46%)