Micronutrients are abundantly present in the soil but plants usually acquire them in relatively trace amounts; hence, regarded as tracer element. B, Cu, Fe, Mn, Zn, Mo and Ni are such micronutrients required in minute amounts by plants but inexorably play an eminent role in plant growth and development. Plant metabolism, nutrient regulation, reproductive growth, chlorophyll synthesis, production of carbohydrates, fruit and seed development, etc., are such effective functions performed by micronutrients. These tracer elements when present at adequate level, elevate the healthy growth in plant physiological, biochemical and metabolic characteristics while their deficiency promotes abnormal growth in plants. Prevalence of micronutrient deficiency has become more common in recent years and the rate of their reduction has further been increased by the perpetual demands of modern crop cultivars. Micronutrients in crop production are important and they deserve equal attention similar to that of macronutrients.

1. CREDIT SEMINAR
ON
ROLE OF MICRO NUTRIENTS IN FIELD CROPS
Advisor: Presented by:
Dr. Biswarup Mehera Vikram Pal
Dean (NAI SHUATS) Ph.D. Agronomy
Department of Agronomy. ID.No.21PHAGRN102

2. INTRODUCTION
 The word ‘micronutrients’ represents some essential nutrients that are required very
small quantities for the growth of plants and micro-organisms.
 There are 17 essential elements for plant growth, out of these elements 8 elements are
considered as micronutrients. They are – iron (Fe), manganese(Mn), copper(Cu),
zinc(Zn), boron(B) molybdenum(Mo), nickel(Ni) and chlorine(Cl).
 Out of these micronutrients iron (Fe), manganese(Mn), copper(Cu), zinc(Zn), behave
like cations, and boron(B) molybdenum(Mo), and chlorine(Cl) behave like as anion.
So that the chemistry of micro- nutrients cations are different from micro- nutrients
anions.
 Among these 8 micro- nutrients, the content of iron (Fe) in soil as well as in plants is
the highest and sometimes higher than even P and S content.
 Micronutrients are also called trace elements, oligo elements or spurn elements.

3. IRON – MAJOR FUNCTION
 Iron is involved in the production of chlorophyll.
 Oxygen carrier.
 Nucleic acid metabolism.
 Chlorophyll synthesis.
 Required for nitrogen fixation.
IRON – DEFICIENCY SYMPTOMS
 Symptoms of iron deficiency start on younger leaves. Plants show chlorotic leaves
with interveinal stripes.
 interveinal yellowing and chlorosis of emerging leaves
 whole leaves become chlorotic and then very pale.
 Whole plants turning – necrotic.
 younger leaves exhibit interveinal chlorosis.
Fe-deficiency in Rice & Maize

4. Manganese – major function
⚫ Manganese is necessary in photosynthesis, nitrogen metabolism and to form other
compounds required for plant metabolism.
⚫ It take part in electron transport in photosysytem.
Mn act as enzyme activation, and this enzyme produceamino acid.
Deficiency symptoms:-
 In addition to interveinal chlorosis on young leaves, grey or tan necrotic spots
develop in chlorotic areas.
 A chlorosis in young leaves increases to a uniform yellow a gray metallic purplish
luster develops on the appear surface. Upward curving of blade margins.
Due to Mn deficiency :-
 1.gray speck in Oat
 2.marshy spot in pea.
Mn-deficiency in Sugacane
MANGANESE –MAJOR FUNCTION

5. Copper – major function
⚫ Copper is necessary for carbohydrate and nitrogen metabolism.
⚫ Eletron carrier in oxidation –reduction reaction.
⚫ Utilization of iron in chlorophyll synthesis.
⚫ Enhance the fertility of male flower
⚫ Enhance disease resistance in plants
Deficiency symptoms:-While younger leaves have interveinal chlorosis, the tips and
lobes of leaves remain green followed by veinal chlorosis and rapid, extensive
necrosis of leaf blade.
Due to Deficiency of copper-
• Die back in citrus.
• Dark brown necrotic lesions on leaf tips
• Bluish green and chlorotic streaks near the leaf tip
• Rolling of new leave
Cu-deficiency in Barley

6. zinc– major function
 Zinc is an essential component of three enzymes-
1.carbonic anhydrase.
2.Alcoholic dehydrogenase.
3.Suproxide dismutase.
For energy production, protein synthesis, and growth regulation.
 Important in the synthesis of IAA.
 Essential for water uptake.
 Play important role in stablization of protein.
Deficiency symptoms:-
 Plant containing less than 15 ppm Zn than deficiency symptoms will occur.
 Intervinal chlorosis first appear in younger leaves.
 Reduce the size of the leaves- little leaf.
 Mainly occur in calcareous soils.
Due to Zn deficiency fallowing deficiency symptoms will occur.
1. khaira disease in rice.
2. white bud in maize.
3. little leaf in cotton , chilli, brinjal. Citrus mango etc., Zn-deficiency in
Rice

7. Boron– major function
⚫ A primary function of boron is related to cell wall formation.
⚫ Important for pollination and pollen germination.
⚫ Help in ‘k' translocation as well as stomatal opening.
⚫ Calcium metabolism.
⚫ Act as regulator of k/Ca ratio.
⚫ Essential for translocation of sugar.
Deficiency symptoms:-
⚫ Rust-coloured cracks and corking occuron young stems, petioles and flower stalks.
⚫ Terminal buds die giving rise to a witch's broom.
⚫ Young leaves become very thick and leathery and chlorotic.
⚫ Y
oung leaves crinkled.
B-deficiency in Rice

8. Molybdenum-major function
 Mo is important constituent of nitrogenase enzyme , which help in N2 fixation in
legumes crops.
 Mo is essential component of NO3
- reductase enzymes. this enzyme concerted
in chloroplast which catalzes the conversion of NO3
- to NO2
-
 protein synthesis and sulfur metabolism are also affected by molybdenum.
 Molybdenum has a significant effect on pollen formation.
 Also reported to have an essential role in iron absorption and translocation in plants.
Molybdenum deficiency:
 The deficiency symptoms of Mo is first appear In Older leaves, interveinal chlorosis
with some dead spots.
Due to Mo deficiency fallowing deficiency symptoms will occur.
1. whip tail in cauliflower.
2. yellow spot in citrus.
3. scald in beans.
Mo-deficiency in
Maize

9. Chlorine - Functions
 Essential for stomatal opening.
 Cl is related to electrical charge balance in physiological functions in plants.
 It indirectly affects plant growth by stomatal regulation of water loss.
Deficiency symptoms
 highly branched root systems are the main chloride- deficiency symptoms,
which are found mainly in cereal crops.
 Chloride deficient plants show chlorotic and necrotic spotting along leaves
with abrupt boundaries between dead and alive tissue. Wilting of leaves
along margins and highly branched roots are also seen in Cl deficient plants.
 chloride deficiencies have been reported on sandy soils,humid region
with high rainfall area.
 wilting and twisting in wheat due to Cl deficiency.
Cl-deficiency in Wheat

10. Effect of foliar application of micronutrients on wheat yield
Treatments Plant
height
(cm)
No. of
spikes/m2
No. of
spikelet/
spike
No. of
grains/
spike
Grain yield
( kg/ha)
Control 99.7 368.0 19.9 57.8 6267.85
Cu 500ppm 108.6 425.3 21.1 64.3 7039.28
Mn 500 110.3 436.4 21.5 65.2 7167.85
Fe 500 108.5 423.1 21.3 64.7 7071.42
Zn 500ppm 112.1 445.7 21.7 66.1 7342.8
Mixture 116.1 468.9 22.1 69.8 7517.85
CD 5% 0.9 7.8 0.2 0.5 S
Seadh et al.(2009)

11. Effect of zinc on grain and Stover yield of maize
Zn levels
( kg/ha)
Grain yield
(q/ha)
Stover yield
(q/ha)
0 25.04 63.86
2.5 27.35 69.01
5 29.70 74.83
10 29.00 71.82
CD (P=0.05) 1.25 3.06
Dwivedi et al.(2002)

12. Effect of zinc application on yield and yield attributes of
rice
Zinc
(Kg/ha)
Plant
height
( cm)
No. of
panicle /
sq.m
Days to
maturity
Yield
( t/ha)
0 95.8 299.7 130.5 5.47
15 92.4 334.8 128.3 5.96
30 94.4 338.7 127.3 5.75
45 93.9 342.8 124.8 5.76
CD 5% NS NS NS NS
Yakan et al. 1999

13. 51
Conclusion
 Micronutrients in crop production are important, and they deserve equal
attention similar to that of macronutrients.
 Micronutrient deficiency drastically affect the growth and inhibits different
metabolic and enzymatic activities.
 Application of micronutrients significantly increases the yield of cereal,
vegetables, oilseed and pulse crops.
 Micronutrient application also enhances the uptake of nutrients like N,P,K and S.