During M.Sc. Submitted My Advisor Dr. R.K. Niranjan

1. WEL COMEWEL COME

2. Importance of Zinc for crop production
By
Mr. Chetan Kumar Dotaniya
Credit Seminar
Seminar incharge
Dr. R.K. Niranjan
Department of Soil science and Agricultural
Chemistry
Bundelkhand University Jhansi

3. ZINC
Zinc is one of the trace element which is essential
for the normal growth and development of crops.
 Symbol-Zn
Atomic No-30
Earth crust 24th abundant element
The total zinc content of a soil is largely dependent
upon the geochemical composition of the
weathering rock parent material.

4. Essentiality of Zn was discovered by- A. L. Sommer
and C. P. Lipman 1926.
Zinc is plant micronutrient which is involved in many
physiological functions its inadequate supply will reduce
crop yields.
Beside its role in crop production Zn plays a part in the
basic roles of cellular functions in all living organisms.

5. In soil Zn content in Indian soils varies from
Arid and semi-arid climate 20-89 mg/ kg
Humid and sub- humid tropics 22-74 mg/ kg
Vertisol 69-76 mg/ kg
Oxisols (Coarse textured) 24-30 mg/ kg

6. Soil Types Associated with Widespread Zinc
Deficiency in Crops
Calcareous soils
 Sandy soils
 Strongly weathered deep tropical soils
Saline and Sodic (salt-affected) soil
 Vertisols
 Gleysols (poorly drained/waterlogged soils).

7. Zinc in plants
Zn concentration in plant ranges between 25-150 ppm
Zn deficiency < 10-20 ppm
Toxicities >400 ppm
Plant absorb zinc mainly as Zn2+
ions.

8. Forms in soil solution
At pH values below 7.7, Zn2+
predominates, but above
pH 7.7, ZnOH+
is the main species, and above pH 9.11
the neutral species Zn (OH) 2
is dominant.
Total Zinc Concentrations in Soils
The range of total zinc concentrations in soils reported
in the literature tends to show an overall mean total
concentration of around 55 mg Zn kg-1
. Kiekens reported
a typical range of zinc in soils of 10-300 mg kg-1
with a
mean of 50 mg Zn kg-1
.

9. Igneous Rocks Sedimentary Rocks
Ultramafic 58 ppm Limestone 20 ppm
(e.g. dunite, peridotite and
serpentinite)
Basalt and Gabbro 100 ppm Sandstone 30 ppm
Diorite and Andesite 70 ppm Clays and Shales120
ppm
Granite 48 ppm Bituminous shales
200 ppm

10. Zinc in soils occurs in the following forms
 Free ions (Zn2+
and ZnOH+
) and organically
complexed zinc in solution.
 Adsorbed and exchangeable zinc held on surfaces of
the colloidal fraction in the soil, comprising: clay
particles, humic compounds and iron and aluminium
hydrated oxides.
 Secondary minerals and insoluble complexes in the
solid phase of the soil.

11. Zinc– major function
Zinc is an essential component of three enzymes
carbonic anhydrase.
Alcoholic dehydrogenase.
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.

12. Deficiency symptoms:-
Plant containing less than 15 ppm Zn than deficiency
symptoms will occur.
Chlorosis- yellowing of leaves; often interveinal; in
some species, young leaves are the most affected, but
in others both old and new leaves are chlorotic.
Necrotic spots - death of leaf tissue on areas of
chlorosis.
Bronzing of leaves – chlorotic areas may turn bronze
coloured.
Rosetting of leaves - zinc-deficient dicotyledons often
have shortened , internodes so leaves are clustered on
the stem.

13. Stunting of plants - small plants may occur as a
result of reduced growth or because of reduced
internode elongation.
Dwarf leaves ('little leaf') - small leaves that often
show chlorosis, necrotic spots or bronzing.
Malformed leaves - leaves are often narrower or have
wavy margins.

14. Interveinal chlorosis and necrotic Chlorosis and necrotic spots
patches on leaves of wheat. on the leaves of zinc deficient
wheat.

15. Maize zn deficencyWheat zn deficency

17. Zinc toxicity
Reduces root growth
Resulting in yellowing leaves and eventual plant
death.

18. Due to Zn deficiency fallowing deficiency symptoms
will occur.
 khaira disease in rice.
 white bud in maize.
 little leaf in cotton , chilli, brinjal, Citrus mango. Etc.
 bronzing in Guava.

19. DISEASE RESISTANCE REPORTED BY ZINC
APPLICATION
Crop Disease
Cotton Root rot
Beans Bacterial blight
Turnip Mildew
Tomato Tomato leaf mould
Maize Smut
Potato/Tomato Blight
Maize (Insect attack) Billbug / Gall Nematodes

22. Factors Affecting the Availability of Zinc in
Soils
 pH
Organic carbon
Calcium carbonate
Soil texture
Soil temperature
Soil flooding

23. Effect of zinc on microbial activity
 Microorganism requires various nutrients for their
growth and metabolism.
 Among the nutrients, Zn is an element present in the
enzyme system as co-factor and mental activator of
many enzymes.
Zinc might limit the growth of bacteria at higher levels
(>13.60 mg kg-1
). Furthermore, cell growth as well as
microbial populations and their activity in soil were badly
affected under high levels of Zn.

24. Zinc Interaction with Other Nutrients
N x Zn
Zn x P
Zn x K
Zn x Ca/Mg
Zn x S
Zn x Cu
Zn x Fe
Zn x Mn
Zn x Mo
Zn x B

25. Method of zinc application
Method of application of zinc also depends upon zinc
fertilizer used. With soluble zinc fertilizers such as zinc
sulphate, band placement is generally superior to
broadcast application, while for less soluble fertilizers
such as ZnO and Zn first broadcast application is better.
Foliar application, however, needs lesser quantity of
zinc; generally 6 Kg ZnSO4
applied through foliage
equals 25 Kg ZnSO4
applied through soil.

26. Commonly Used Zinc Fertiliser Materials
Compound Formula Zinc
Content (%)
Inorganic compounds
Zinc sulphate monohydrate ZnSO4.H2O 36
Zinc sulphate heptahydrate ZnSO4. 7H2O 22
Zinc oxysulphate xZnSO4.xZnO 20-50
Basic zinc sulphate ZnSO4.4Zn(OH)2 55
Zinc oxide ZnO 50-80
Zinc carbonate ZnCO3 50-56
Zinc chloride ZnCl2 50
Zinc nitrate Zn(NO3)2.3H2O 23

27. Organic Compounds (Chelated Zinc)
Disodium zinc EDTA Na2ZnEDTA 8-14
Sodium zinc HEDTA NaZnHEDTA 6-10
Sodium zinc EDTA NaZnEDTA 9-13
Zinc polyflavonoid 5-10
Zinc lignosulphonate 5-8

28. One transformation is quite different from transformations
associated with macronutrients-- chelation.
The word chelate means “claw”. Chelation refers to the
process in which organic molecules in the soil form a
complex with micronutrient ions.
 The chelated micronutrients are carried by mass flow
and diffusion to the root surface.
Transformations in the soil - chelation processTransformations in the soil - chelation process
Role of chelation in nutrient availabilityRole of chelation in nutrient availability

29. Chelated micronutrients are widely used in agriculture and are
strongly.
promoted by the fertilizer industry. Exactly what are they and why
should they be used?
The word chelate is derived from the Greek word for “claw”. In
fertilizer technology, it refers to inorganic nutrients that are
enclosed by an organic molecule.
Advantages of Chelates
1.Much lower quantities are necessary compared to inorganic
compounds.
2.Chelates are much more easily absorbed by plant roots or
leaves because chelates are of organic nature.
3. Chelates are more easily translocated within the plant as their
action is partly systemic.
4.Chelates are not readily leached from the soil as they adsorb
on to the surface of soil particles.

31. Zinc deficiency is recorded in 45 to 50% soils of India
Deficiency is affecting productivity of many crops
Wheat though less sensitive to Zn deficiency, yield
reduction seen
To keep pace with growing population, yield should be
increased
Correction of Zn deficiency has the potential to improve
crop production.