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Primary Nutrients
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Primary nutrients
Introduction
Nitrogen (N), Phosphorous (P)
and Potassium (K) are often
referred to as primary nutrients.
They are most common elements
found in commercial fertilizers.
The above three essential nutrients
are frequently managed by the
addition of fertilizers to soils.
While the others are usually found in
sufficient quantities in most soils and no
soil amendments are usually used.
Primary nutrients are usually lacking
in soil because plants use them in
large amounts for their growth and
survival.
Primary nutrients
Nutrient Deficiency
A nutrient deficiency occurs when the
nutrient is not in sufficient quantity to
meet the needs of the growing plant.
Nutrient Toxicity
Nutrient toxicity occurs when a
plant nutrient is in excess and
decreases plant growth or quality.
Primary nutrients
Types of deficiency symptoms (NPK)
Chlorosis – yellowing of plant
tissue due to limitations on
chlorophyll synthesis.
Necrosis - death of plant
tissue sometimes in spots.
Accumulation of anthocynanin resulting in a purple or reddish
color .
Lack of new growththe development of new
leaf reduced.
Stunting or reduced growth new growth continues but it
is stunted or reduced
compared to normal plants.
Primary nutrients
Brief key to deficiency symptoms of Primary Nutrients
Symptoms
Deficiency of Nutrients
Symptoms appearing first on older leaves:
Chlorosis starting from leaf tip
N
Reddish colour on green leaves or stem
P
Necrosis on leaf margins
K
Primary nutrients
Role of nitrogen (N) in plants
It is a part of all living cells and a
necessary part of all proteins,
enzymes and chlorophyll, etc.
It helps plants with rapid growth,
increasing seed and fruit production
and improving the quality of leaf and
forage crops.
Nitrogen often comes from fertilizer
application (mainly urea) and from
the air (legumes get their N from the
atmosphere, water
or rainfall
contributes very little nitrogen)
Primary nutrients
Primary nutrients
Nitrogen (N) deficiency in maize
Chlorosis (yellowing) at the tip
of the oldest leaf.
Chlorosis continues to
the next oldest leaf
Primary nutrients
Role of phosphorus (P) in plants
It is involved in the formation of all
oils, sugars, starches, etc.
Helps with the transformation of solar
energy into chemical energy; proper plant
maturation; withstanding stress.
Helps in rapid growth, encourages
blooming and root growth.
Phosphorus often comes from
fertilizers, bone meal, and rock
phosphate.
Primary nutrients
Phosphorous (P) deficiency in maize
Purple coloration of lower leaves
Primary nutrients
Role of potassium (K) in plants
Potassium is removed by plants in
larger amounts than any other
mineral element except nitrogen.
It helps in the building of proteins ,
photosynthesis, fruit quality and
reduction of diseases.
Potassium is supplied to plants by
soil minerals, organic materials,
and fertilizers.
Primary nutrients
Potassium (K) deficiency in maize
Chlorosis at the tip of the oldest
leaf progressing toward the
base along the leaf margins
Primary nutrients
Forms of primary nutrients for plant uptake
+
Nitrogen – NH4 , NO3
-
-
Phosphorus – H2PO4 , HPO4
+
Potassium – K
—
Primary nutrients
Sources of primary nutrients
Organic manures: Farmyard
manure, green manure,
composts, vermicompost,
crop residues, oilcakes
Biofertilizers: Azotobacter,
Rhizobium (N)
Chemical fertilizers: Urea (N),
DAP (NP), SSP (P), Muriate of
Potash (K) and potassium
sulphate (K)
Primary nutrients
Sources of primary nutrients
Vermicompost
Farmyard manure
Bacteria N2 fixation Rhizobium,Bradyrhizobium with legumes
Primary nutrients
Urea (Source of Nitrogen)
Chemical fertilizers
MOP (Source of Potassium)
Primary nutrients
Let us sum up
Nitrogen, phosphorus and potassium
are considered as primary nutrients.
Knowledge of the properties and
functions of these nutrients is helpful
for
their
efficient
and
proper
management.
These nutrients are needed by plants
in higher quantities and, thus, essential
for good plant growth and high yields.
Plants exhibit many shades of
greenness (chlorosis) or other
deficiency symptoms in case of
insufficient supply.
Primary nutrients can be supplied
through different organic sources,
chemical fertilizers and bio-fertilizers.
End