Essential plant nutrients and their functions and deficiency symptoms

Essential plant nutrients and their functions and deficiency symptoms

Generally, 90-95% parts of all plants are made up of carbon, hydrogen and oxygen and the remaining 5-10% is made up of other essential plant nutrients.

The following are the essential nutrients for plants.

Major Nutrients

1) Carbon
2) Hydrogen
3) Oxygen

4) Nitrogen
5) Phosphorus
6) Potassium

Secondary Nutrients

7) Calcium
8) Magnesium
9) Sulfur


10) Iron
11) Manganese
12) Zink
13) Copper
14) Molybdenum
15) Boron
16) Chlorine

Other beneficial plant nutrients

17) Cobalt
18) Sodium
19) Vanadium
20) Silico

Now we know one by one about the functions of all plant nutrients and their deficiency symptoms.

Table Of Contents show

Carbon, Hydrogen, Oxygen

Plants get Carbon from CO2, Oxygen from ‘water and CO2‘ and Hydrogen from water. Hydrogen and Oxygen together again ‘react’ with water and carbon to form various organic compounds for plants.


Nitrogen is absorbed by the roots of plants in the forms NO3 and NH4+.

Functions of Nitrogen in plants

1) Nitrogen plays a major role in the formation of green color (chlorophyll) and protein in leaves.

2) Nitrogen takes an active part in the formation of amino acids, nucleic acids, vitamins, hormones, enzymes and protoplasm in plants.

3) With the use of Nitrogen, “phosphorus and potassium fertilizers are used by plants in a balanced form”.

4) Enhances the properties of leafy vegetables and the leaves become juicy.

5) The use of nitrogen accelerates vegetative growth but slows down the growth of roots.

6) Nitrogen helps in the rapid decomposition of organic matter.

7) Tillerings are high due to the use of nitrogen in crops like sugarcane, wheat, barley and oats.

8) By using more nitrogen, the plants grow more, due to which the stems of the plants remain soft and the crop starts lodging.

9) Insect moths are more attracted towards soft plants and the attack of diseases also increases.

10) Sometimes, the yield and quality of crops are also reduced due to excessive application of nitrogen.

Deficiency symptoms of nitrogen in plants

1) Due to lack of nitrogen, there is a lack of chlorophyll in the leaves of the plants, due to which the leaves turn light yellow.

2) Due to the high mobility of nitrogen in plants, the symptoms of deficiency first appear on the older (lower) leaves, then the new leaves are affected on the upper side.

3) Leaves and veins turn yellow.

4) Plants remain dwarf.

5) Tillering is less in crops like wheat, sugarcane, barley etc.

6) Due to excessive deficiency of nitrogen, the leaves turn white in color and the leaves dry up and fall down.

7) The problem of fruit drop is seen in fruit trees.


From the point of view of plant nutrition, phosphorus comes second after nitrogen. Plants absorb phosphorus mainly in the form of H2PO4 and HPO42- ions. Small amounts of phosphorus are absorbed by plants in the form of pyrophosphate, metaphosphate soluble organic phosphates, phytin and nucleic acids.

Functions of phosphorus in plants

1) With the use of phosphorus, the growth of plant roots is faster and stronger, which is helpful in sucking other nutrients from the soil.

2) The use of phosphorus increases the resistance of plants against pests and diseases.

3) Lodging resistance increases in the crop.

4) With the use of phosphorus, the production of fruits, flowers and seeds increases.

5) The quality of vegetables and grains increases.

6) Phosphorus helps in the absorption of potassium by plants.

7) Pollination is good in crops when the amount of phosphorus is sufficient.

8) Phosphorus increases the assimilation of other plant nutrients.

9) The root development of leguminous crops is good when phosphorus is sufficient, which leads to better fixation of atmospheric independent nitrogen in plants; As a result, the amount of protein in plants also increases.

10) In the presence of phosphorus, fruits come early, fruits are formed early and the crop matures early.

11) Phosphorus reduces the side effects of nitrogen.

12) The use of phosphorus increases the yield and quality of crops.

13) With the use of phosphorus, plant starch is easily converted into sugar.

Deficiency symptoms of Phosphorus in plants

1) Due to the high mobility of phosphorus in plants, the symptoms of phosphorus deficiency first appear on the lower leaves and then appear on the upper leaves.

2) Due to the deficiency of phosphorus, the leaves become dark green in color and the lower surface of the leaves becomes light purple or brown in colour.

3) Due to the deficiency of phosphorus, the leaves turn blue in pulse crops.

4) In tobacco, the leaves become thin and sharp in the shape of rosettes.

5) Due to the lack of phosphorus, the leaves in potato take the shape of a cup.

6) Deficiency of phosphorus causes small leaves in broad-leafed plants.

7) The length of the internode is less.

8) Due to the lack of phosphorus, the growth and development of the roots of plants is very low, due to which the roots remain shallow and sometimes dry up.

9) There is a “decrease and delay” in the germination of one-year (annual) plants and the crop also matures late.

By the time the crops show signs of phosphorus deficiency, the time for phosphate application has passed; But its deficiency can be overcome in long duration crops and fruit trees.

Nowadays, phosphatic fertilizers have also become available in liquid form in the market, so phosphorus deficiency can be overcome by spraying an appropriate amount of phosphatic fertilizers even in short duration crops.

But to save the crops from the effects of phosphorus deficiency, it is best that the amount of phosphate must be determined while preparing the crop plan.


Plants absorb potassium in the form of K+. Potassium is essential for the following important functions of plants.

Functions of Potassium in plants

1) Potassium helps in the translocation of nutrients inside plants.

2) Potash increases the efficiency of plant leaves. Due to which a sufficient amount of chlorophyll is produced in the plant.

3) Potash helps in the smooth translocation of starch and sugar substances synthesized in the leaves and other parts of the plant from the place of their storage to the roots.

4) Helps in the metabolism of nitrogen and the formation of proteins.

5) Potassium controls water conservation, degradation and evaporation by stomata of leaves.

6) In the presence of potash, food is produced in plants quickly and smoothly.

7) If there are more cracks in the soil, the physical condition of the soil is also improved by the use of potash salts because potassium salts combine with the calcium carbonate of the soil to form potassium carbonate, which binds the soil particles.

8) On the contrary, if the land is heavy such as clay soil, then due to the formation of potassium carbonate, the soil becomes more dense, as a result, there is difficulty in ploughing of the soil and its basic condition deteriorates.

Deficiency symptoms of potassium in plants

1) Potassium is a very dynamic element in plants, so its deficiency symptoms first appear on older (lower) leaves.

2) Due to the deficiency of potassium, the tips and sides of the leaves appear scorched or burned.

3) Sometimes the leaves start to thicken and the tip of the leaves start twisting.

4) Deficiency of potash causes the main veins of the leaves to remain green, which later dry up to form a reticulated structure.

5) Due to potassium deficiency in potatoes, the leaves become dark green in color which later changes to yellow, brown and bronze color and the size of the tubers remains small.

6) Small spots appear between the veins of tobacco leaves, at the ends or margins as the tissue becomes lifeless.

7) Due to the deficiency of potassium, the corn kernels become small and sharp and the grains are less formed at the top of corn kernel.

8) The symptoms of potassium deficiency first appear in moist areas in the field.

9) Unavailability of potash reduces the process of photosynthesis by increasing respiration in plants.

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Plants absorb calcium in the form of Ca2+. Following are the main functions of calcium in soil.

Functions of Calcium in plants

1) Calcium helps in the development of roots and growing buds of plants.

2) Calcium is essential for cell growth and cell wall formation.

3) Calcium makes the grains and stems hard in plants.

4) Calcium develops root nodules in leguminous crops.

5) Calcium is helpful in carbohydrate operation in plants.

6) Calcium neutralizes the effect of organic oxalic acids in plant metabolism.

7) In the presence of calcium, the absorption of nitrate by the plant roots increases and protein formation is increased.

8) Calcium helps in the growth of primary roots and root hairs in plants.

Deficiency symptoms of calcium in plants

1) Deficiency of calcium leads to drying of terminal buds.

2) Due to calcium deficiency, buds and fruits wither in immature stage.

3) Root development remains incomplete.

4) The edges of the new (upper) leaves are curled and wrinkled.

5) The margins and tip of the leaves may die.


Plants absorb magnesium in the form of Mg2+.

Functions of Magnesium in plants

1) Magnesium is mainly helpful in the formation of chlorophyll in plants.

2) Helps in the translocation of nutrients inside the plants and absorption of nutrients in plants.

3) Many enzymatic activities inside the plant take place smoothly in the presence of magnesium, which helps in the formation of proteins, fats and carbohydrates.

4) Magnesium helps in phosphate metabolism and plant respiration.

Deficiency symptoms of magnesium in plants

1) Due to the high mobility of magnesium in plants, the symptoms of Mg deficiency first appear on older leaves.

2) Magnesium deficiency causes chlorosis in plants.

3) The colour of the lower (old) leaves of the plant is lost from the tip and margins and later the colour of the entire leaf is lost.

4) The veins remain green.

5) In cotton, the leaves can be light purple in color with green veins.

6) Magnesium deficiency causes leaves to become smaller in size and curl upwards.

7) Deficiency of magnesium leads to fruit drop from trees.

8) Leaves of plants of lemon species become speckled.


Sulfur is absorbed by the roots of plants in the form of SO42- ions and by the leaves in the form of SO2 gas.

Deficiency symptoms of Sulfur in plants

1) Sulfur enhances the resistance against diseases in plants.

2) Sulfur develops roots and increases the number of tillerings in crops.

3) Sulfur increases oil content in oilseed crops by 4-9%.

4) Sulfur is essential for the synthesis of essential oils in plants.

5) Adequate amount of sulfur in the field increases the yield of tobacco by 15-20%.

6) The formation of root nodules is accelerated in pulse crops.

7) Sulfur is essential for onion, garlic and mustard crops. The odor coming from onions and garlic is formed due to sulfur.

8) Sulfur helps in the formation of chlorophyll in the leaves of plants.

9) Sulfur produces a characteristic odor in plants of the Cruciferous species.

10) The presence of sulfur increases the absorption efficiency of nitrogen and phosphorus in plants.

11) Sulfur helps in the formation of vitamins biotin, thiamine and B1.

12) Sulfur is an essential component in the formation of glutathione.

Deficiency symptoms of sulfur in plants

1) Symptoms of sulfur deficiency in plants are similar to those of nitrogen, although the symptoms of sulfur deficiency first appear on the upper part of the plants because sulfur is not motile in plants.

2) Due to the deficiency of sulfur, the veins of the upper leaves (new leaves) of the plant and the parts between the veins become light greenish yellow.

3) The stems and leaves of the plant become short, thick and hard.

4) Flowers and fruits are less in banana, coconut etc.

5) Potato, mustard and tea leaves become bowl-like (cupping).

6) In cotton, lucerne, rapeseed, maize, tomato the stem or stalk becomes red in color.

7) Root nodules are less formed in leguminous crops.

8) Sulfur deficiency occurs in areas where there are sandy lands and organic matter is less or rainfall is more. In irrigated areas and sandy lands, sulfur is lost in the form of sulphate due to leaching.


Iron is absorbed by plants in the forms of Fe2+ and Fe3+.

Functions of Iron in plants

1) Iron helps in the formation of chlorophyll in plants.

2) Iron is involved in protein synthesis and metabolic activities.

3) Iron acts as an oxygen carrier in respiration in plants.

4) Iron is essential in cell division in plants.

5) It acts as a prosthetic group in the nitrate reductase enzyme.

Deficiency symptoms of Iron in Sulfur

1) The new (upper) leaves of the plant turn yellow and the veins remain green.

2) The margins of the leaves remain green for a long time and in severe deficiency the leaves turn white.

3) The plant remains small or dwarf.

4) In lemon the leaves and twigs dry up, and the underripe fruits drop.


Manganese is absorbed by plants in the form of  Mn2+ and accumulates in plant parts that are actively involved in physiology.

Functions of Manganese in plants

1) Manganese helps in the formation of chlorophyll in plants.

2) Manganese helps in the assimilation of nutrients in plants.

3) It is essential in the metabolism of proteins and carbohydrates in plants.

4) The functions of manganese are closely related to the functions of iron in plants. It is helpful in the conduction of iron in plants.

5) Manganese acts as a catalyst in various plant growth processes such as oxidation and reduction.

6) It activates an enzyme which helps in the reduction of nitrate to ammonia.

Deficiency symptoms of Manganese in plants

1) Due to deficiency of manganese, the leaves of plants become light green in color and in extreme deficiency, the light green color becomes gray or white.

2) Deficiency of manganese causes chlorotic spots on the veins of the leaves.

3) Small veins remain green.

4) Due to deficiency of manganese, leaves of cereal crops turn brown and cause tissue rot.

5) Deficiency of manganese causes diseases like gray speck of oats, yellow spotted disease of beet, mars spot of peas, blight of sugarcane etc.

6) Symptoms of manganese deficiency first appear on the young leaves (upper leaves) of plants.


Nowadays, like the main plant nutrient, zinc is becoming deficient in the lands of our country. The main reason for zinc deficiency is the sowing of high yielding varieties of crops, because high yielding species absorb a large amount of zinc from the soil.

Apart from this, due to less use of organic manures like farmyard manure, compost etc. and intensive farming, zinc deficiency is also happening in the lands. Zinc deficiency is found in those lands where nitrogen and phosphorus are used in high quantity in crop production.

Plants absorb zinc in the form of Zn2+.

Functions of Zinc in Plants

1) Zinc increases the water absorption capacity of plants.

2) Zinc is helpful in the utilization of iron, so in plants it is indirectly combined with iron and manganese in the formation of chlorophyll.

3) Zinc helps in oxidation in plants.

4) Zinc helps in the translocation of carbohydrates in plants.

5) Zinc plays an important role in photosynthesis and nitrogen metabolism in plants.

6) It is helpful in the synthesis of protein, carotene and citrine in plants.

7) Zinc increases the activity of enzymes like enolase, lecithinase, cysteine, disulfidase etc.

8) Zinc is a constituent element of the enzymes alcohol dehydrogenase, carbonic anhydrase and peptidase.

Deficiency symptoms of zinc in plants

1) Symptoms of zinc deficiency appear simultaneously on new and old leaves.

2) Leaves become smaller (especially in fruit trees), the leaves may curl and form a rosette structure.

3) Necrosis in the veins of the leaves and yellow stripes between the veins are seen.

4) Due to zinc deficiency, after 2-4 weeks of sowing, the midribs of the newly emerging leaves appear colorless at the base and brown spots appear on the older leaves.

5) The margins of the leaves roll up and twisted.

6) Leaves turn pale yellow or ivory in color.

7) Due to zinc deficiency, dark brown, rust-like spots appear on the leaves of wheat and other cereal crops.

8) The size of the fruit becomes smaller and the production of seeds in the fruit decreases.

9) The problem of dieback is seen in young plants due to zinc deficiency.

10) Zinc deficiency in plants is accompanied by an increase in phosphorus availability.

Diseases/Disorders caused by Zinc deficiency in plants

Khaira disease of Paddy

In paddy, after 3-4 weeks of sowing, brown red spots appear on the leaves. The spots first appear in the middle of the leaves and then gradually spread to the entire leaf.

The affected cell group becomes papery or necrotic. Leaves fall down due to excessive zinc deficiency.

White bud in maize

After germination, light yellow and white spots appear on the leaf veins of maize leaves, which later turn brown. The newly emerging leaves appear pale yellow and white.

Small leaves in flowering trees

Leaves are mostly small, twisted and yellow in size, and later appear like rosettes.


Copper is absorbed by plants in the form of Cu2+. Copper is found in greater amounts in the root zone of plants than in the stem and leaves.

Functions of Copper in Plants

1) Copper helps in the utilization of ammoniacal nitrogen by the roots in plants.

2) Copper helps in the formation of vitamin A and Indole-3-acetic acid (IAA) in plants.

3) It helps in the utilization of iron, in the formation of chlorophyll.

4) Copper is involved in photosynthesis and respiration in plants.

5) It combines with proteins and amino acids to form many compounds inside the plant and plays an important role in the metabolic activities of proteins.

6) Copper acts as an “electron” carrier for enzymes present in plants that affect oxidation and reduction processes in plants.

Deficiency symptoms of copper in plants

1) Deficiency of copper causes chlorosis at the edge and tip of young leaves.

2) Leaves of cereal crops get bleached.

3) Deficiency of copper causes the wilting of leaves.

4) Due to copper deficiency, the leaves break off easily from the stem and drop.

5) The problem of die back occurs in the new growth parts in the plants of lemon family.

6) In the fruits of lemon species, gum accumulates in the middle medulla and leaves become disfigured.

7) Deficiency of copper causes a disease called reclamation in cereals and leguminous crops.

8) Acid formation is less in fruit juices.


Boron is absorbed by plants in the forms Bo32-, H2BO3and HBO32-.

Functions of Boron in Plants

1) Boron is essential for flower, fruit and seed formation in plants and for pollination and reproduction.

2) It is essential for the translocation of sugars in plants.

3) Boron controls water absorption in plants.

4) It helps in the absorption and utilization of calcium in plants.

5) Boron helps in cell division and formation of the cortex in plants.

6) It is essential for Rhizobium (symbiotic) bacteria in leguminous crops.

7) Boron helps in the synthesis of pectin, ATP, DNA and RNA in plants.

8) Plants can die if plants take in excessive amounts of boron.

9) Boron is essential for the growth of meristematic tissues.

Deficiency symptoms of Boron in Plants

1) Deficiency of boron causes a light green color of terminal buds of plants.

2) The top of the plants become colorless and twisted.

3) Due to boron deficiency, lateral buds do not develop.

4) Due to the deficiency of boron, the leaves of plants show thickening, hardness, curling, wrinkling, drying and chlorosis.

5) In some plants the stems burst.

6) Deficiency of boron causes diseases like internal cork in apple, yellow fungus in rijka, internal rot in beet, hard fruit in citrus, leaf roll in potato and peak disease in tobacco.

7) Due to the deficiency of boron, the size of cauliflower becomes deformed and small, and red spots appear on the flower.

8) Excessive boron deficiency can result in the death of the terminal bud.


Molybdenum is absorbed by plants in the form of MoO42-.

Functions of Molybdenum in Plants

1) Molybdenum is essential for nitrogen fixation bacteria in the roots of leguminous crops.

2) Molybdenum is required for the fixation of free nitrogen in the soil by Azotobacter bacteria.

3) It helps in the formation of sugar and vitamin C in plants.

4) It actively involves in the metabolism of phosphorus.

5) Molybdenum is essential for nitrate reduction, where it acts as an electron (e) carrier.

Deficiency symptoms of Molybdenum in plants

1) Symptoms of molybdenum deficiency in plants are similar to those of nitrogen deficiency.

2) Deficiency of molybdenum leads to scorching of leaf margins, yellowing and mottling of stem and leaves.

3) Dead necrotic spots appear over the leaf except on the veins.

4) Affected areas may extrude a resinous substance from the under surface of leaf.

5) Symptoms of molybdenum deficiency appear on older leaves of plants.

6) The symptoms of molybdenum deficiency are clearly visible on leguminous crops and the nodules in the roots of leguminous crops remain weak.

7) A whiptail-like structure formed in cauliflower.

8) Leaves of oats bend backwards, later necrosis occurs and the affected area cracks and falls off.

9) Deficiency of molybdenum leads to molting, necrosis and curling of leaf margins in older leaves of tomato.


Plants absorb Chlorine in the form of Cl.

Functions of Chlorine in plants

1) Chlorine enhances the water holding capacity of plants in their leaves.

2) Chlorine increases the osmotic pressure of the cells.

3) Chlorine involves in the photolysis process in plants.

4) Chlorine helps in the removal of oxygen in the process of photosynthesis.

5) Chlorine affects carbohydrate and protein metabolism.

Deficiency symptoms of Chlorine in plants

1) Symptoms of chlorine deficiency are rarely seen in crops.

2) Deficiency of chlorine in pots results in wilting of leaves.

3) Leaf curls in cabbage due to lack of chlorine.

4) Berseem leaves become smaller and thicker.

5) Chlorosis necrosis on leaves and unusual types of bronze colored formations are found on tomato plants.

6) Fruits are not formed due to excessive chlorine deficiency.

Other Beneficial plant nutrients


Although cobalt is not essential for plant growth, its presence in plants is beneficial. Therefore the presence of cobalt in pastures is considered essential. Many diseases can be prevented by applying cobalt fertilizer to many types of grasses that are grown for livestock.

Cobalt helps in the formation of B12 which is helpful in the formation of Leghemoglobin in the nitrogen-fixing root nodules of leguminous plants.


Although sodium is not very essential for plants, some plants absorb it. It acts like potassium in plants. Excess of sodium is harmful to plants.


Vanadium is essential for green algae but its requirement for other plants has not been proven. In the nutrition of Rhizobium and Azotobacter, it can replace Mo in some quantities. The use of vanadium increases the yield of paddy, maize and sugar beet crops.


This cannot be said clearly how plants use silicon. It is believed that plants absorb more phosphorus from the soil in the presence of silicon.

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Hello friends, I am Jitendra Rathore, Author & Founder of "New Agri India". I am graduate in agriculture. I love to share proper knowledge related to agriculture with the people.

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