Essential Nutrients
fact sheet
What are essential nutrients?
Sixteen nutrients are essential for crop growth and development.
Based on the amount required by the plant, they are divided into
 macro nutrients (Nitrogen, Phosphorus, Potassium), Primary (macro) nutrients are
needed in the largest amounts by plants and are the most frequently required in a crop
fertilization program.
 secondary nutrients (calcium, magnesium, and sulfur), Secondary nutrients are needed
in lesser amounts than primary nutrients, but they are increasingly important in crop
fertilization programs.
 micronutrients, chlorine, cooper, iron, manganese, molybdenum, and zinc.
Micronutrients are used in very small amounts, but they are essential for plant
development. Deficiencies occur – often related to specific soil conditions (e.g., pH).
In addition to the above 13 nutrients, plants also require carbon, hydrogen, and oxygen; these are
extracted from air and water and make up the bulk of plant weight.
Nutrient
Functions include
Nitrogen
Protein and ·
photosynthesis
photosynthesis, root
growth, seed quality
Phosphorus
Frequency
of
deficiency
High
Mobility
in plant
Typical symptoms of deficiency
High
High
High
Older leaves, generally at the bottom of
the plant, will yellow.
Small leaves that may take on a
reddish-purple tint. Leaf tips can look
burnt.
Older leaves may look scorched around
the edges and/or wilted. Interveinal
chlorosis develops.
New leaves distorted
Potassium
fruit formation
disease resistance
High
High
Calcium
cell division
fruit set
chlorophyll production
plant enzymes
amino acids
seed production
Pollen, seed and cell
wall formation
maturity
Rare
Low
Increasing
Intermediate
Intermediate
Low
Occasional
Iron
photosynthesis
reproductive stages
chlorophyll
Manganese
chlorophyll synthesis
Rare
Molybdenum
Nitrate reduction
Rare
Intermediate
Zinc
hormones and
enzyme
Increasing
Intermediate
Magnesium
Sulfur
Boron
Chlorine
Copper
Increasing
Increasing
Rare
Increasing
Intermediate
Intermediate
Intermediate
Intermediate
Slow growth, leaves turn pale yellow,
sometimes just on the outer edges.
New growth pale yellow, older growth
stays green.
Poor stem and root growth. Terminal
(end) buds may die.
Stunted growth. Leaves become limp,
curl, or drop.
Growth slows. Younger leaves pale
yellow, often starting between veins.
May develop dark or dead spots.
Older leaves yellow, remaining foliage
light green. Leaves narrow and
distorted.
Yellowing between veins of new growth.
Terminal leaves may rosette.
Prepared by MA Bell February 26 2007
For more information visit: International Programs: www.aes.ucdavis.edu/IntProg/Default.htm
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