Sodium

1. University of Agricultural Sciences Dharawad
Name: Subhashchandra L. Shabannavar
ID.No.: UGS19AGR9443
Course: Soil, Plant, Water, Fertilizer and Manure Testing
AEL-404(0+10)
Topic: Sodium
College Of Agriculture Vijayapura
COURSE TEACHER
Dr. Vidyavathi Yadahalli
Assistant Professor
Department of soil science
AC, Vijayapura

2. Sodium
 Sodium is a chemical element with the symbol Na (from
Latin natrium) and atomic number 11.
 It is a soft, silvery-white, highly reactive metal.
 Sodium is an alkali metal, being in group 1 of the periodic
table.
 The free metal does not occur in nature, and must be
prepared from compounds.
 Sodium is the sixth most abundant element in the Earth's
crust and exists in numerous minerals such as feldspars,
sodalite, and halite (NaCl). Many salts of sodium are
highly water-soluble: sodium ions have been leached by
the action of water from the Earth's minerals over oceons,
and thus sodium and chlorine are the most common
dissolved elements by weight in the oceans.

3. • Sodium at standard temperature and pressure is a
soft silvery metal that combines with oxygen in
the air, forming sodium oxides.
• Bulk sodium is sometimes stored in oil or
Kerosene or under and inert gas, which are the
conditions it is usually stored in.
• Sodium is stored in kerosene because sodium
reacts vigorously with oxygen and moisture due
to its high reactivity so keeping it in kerosene
will prevent sodium from coming in contact
with oxygen and moisture.
• Sodium metal can be easily cut with a knife.
• It is a good conductor of electricity and heat.
This is HOW SODIUM REACTS
WITH WATER..!

4. Sodium for Plants:
• Sodium is not ‘Essential’ but it is ‘Beneficial’ element.
While it is not as critical as other macronutrients like
Nitrogen, Phosphorus, and Potassium.
• Every Crop Species has absorption of sodium and it has
competition with Potassium for absorption.
• It is absorbed by plants in the form of monovalent
i.e. Na+
Plants can be grouped into Two Types:
Based on requirement of Na+
1)Natrophilic Plants
2) Natrophobic Plants
Na+
Na+
Na+
Na+

5. Natrophilic and Natrophobic Plants
Some of the Crop species has more absorption of Sodium, such spp. Are called Sodium
loving spp. Or Natrophilic plant spp.
Example: Sugarbeet(Highly salt tolerant ), Barley
Absorption of sodium through roots and its transportation to shoots is also higher.
Some of the Crop species don’t prefer absorption of Sodium, such spp. Are called
Natrophobic plant spp.
Most of the field crops don’t prefer sodium absorption.
Example: Maize, wheat
Absorption through roots and transportion to shoots is also lower
But sometimes its absorption through roots is higher but its transportation to shoots is
lower.
Mechanism of sodium Flux Pump:
Sodium absorbed along with water from soil solution is pumped back to soil solution to
maintain low sodium concentration in plant system.

6. Role of Sodium in Plant Growth
1.Sodium is essential for Halophytes:
Halophytes are plants that can grown in highly saline soil, sodium is
essential halophytes for osmatic regulation.
Halophytes can’t grow without sodium in soil….?
Halophytes capable to grow in saline condition because sodium
absorbed through roots is stored in vacuoles, which helps halophytes
for osmatic adjustment . If sodium stored outside the vacuole of cell it
will cause toxicity to plants.
Capacity of osmatic adjustment of sodium is more compared to
Potassium that’s why halophytes prefer to accumulate sodium in
vacuole compared to potassium.

7. 2. Sodium is essential for C4 Plants:
• In C4 Plants sodium is necessary for regeneration of
Phosphoenolpyruvate.In Mesophyll cells of C4 Plants , Pyruvate is
converted to Phosphoenolpyruvate.Further this Phosphoenolpyruvate
is essential for Carbon dioxide fixation in C4 plants.
• Sodium protects mesophyll cells from photodestruction where Nitrate
Assimilation takes place.
• Sodium acts as symporter i.e. it carries anions from soil solution to
plant system.
Example: Na+/ NO3-

9. 3. Substitution of Potassium by sodium.
• Sodium replaces potassium in enzyme activation , this replacement mainly
dependent on plant spp. In natrophillic spp. Replacement of Potassium by
Sodium is very high.
• But in Natrophobic spp. replacement of Potassium by sodium is very less.
• And replacement of potassium by sodium is more in vacuoles when
compared to cytoplasm.
• This replacement results in changes in osmatic regulation and enzyme
activation.
This substitution of potassium by sodium disproves criteria of essentiality….?

10. 4. Growth Stimulation:
• Stomatal Regulation: Sodium can also influence stomatal regulation,
which is the process by which plants control the amount of water and
gases that pass through their leaves. This is because sodium ions can
influence the opening and closing of stomata, which affects gas
exchange and water loss.
• It can be used in small quantities similar to micronutrients and helps
in synthesis of chlorophyll.
• It helps in maintainance of cell turgidity and cell expansion.

11. Role of Sodium in Soil
1. Soil structure
Sodium can help improve the structure of the soil by loosening compacted
soil, which makes it easier for roots to penetrate. This is because sodium
has a greater capacity to displace other cations, such as calcium and
magnesium, which can lead to the breakdown of soil aggregates.
2. Water Movement: Sodium can also influence water movement in the
soil. This is because sodium ions have a greater ability to attract water
molecules than other cations, which makes the soil less sticky and easier
for water to penetrate.

12. 3.Sodic soil
High levels of sodium can lead to soil sodicity, which can be harmful to
plant growth. This is because the excessive accumulation of sodium can
cause the soil to become toxic, which can lead to reduced water uptake
and nutrient deficiencies.
How excessive accumulation of sodium reduces water uptake?
There are many different salts in soil that provide nutrients to plants.
However, if there is too much salt in the soil it will interfers water
uptake.
Sodic soil results from excessive sodium salts.
Example: sodium chloride.

13. Each molecule of sodium chloride is made up of sodium ion which is
positively charged and chlorine ion which is negatively charged.
Water is made up of two atoms of Hydrogen and one atom of Oxygen.
Water Is polar molecule i.e. +ve charge on one side and –ve charge on
other side. Sodium chloride also have charges in same way.

14. Due to Polar properties of salt and water , they bind together. When salt comes
contact with water negatively charged chlorine ion comes in contact with
positively charged hydrogen ions.
Meanwhile positively charged sodium ion come in contact with negatively charged
oxygen. In this way One molecule of salt binds to many molecules of water.
When there is a lot of salt and soil, much of water will be bound by salts.
Therefore plants’ roots unable to absorb water from soil solution.

16. What is Sodium Absorption Ratio…?
Soil clay particles are unattached to one another called dispersed or
attached together called flocculated in aggregates . soil aggregates are
combination of sand silt and clay.
Dispersed clay particles Flocculated clay particles

17. • Flocculation is desirable because
water moves through large pores
between aggregates. Also plant roots
mainly grow between aggregates.
• Clay particles are negatively charged
anions and when clay particles
bounded with divalent cations like
Ca2+ and Mg2+ can make soil
particles stick together or flocculate.

18. Ca2+ and Mg2+are good flocculators while Na+ is poor flocculator
which can disperse the clay in soil.

19. The ratio of good flocculator to bad flocculators is expressed as the
Sodium Absorption Ratio (SAR).

20. SAR is the balance between calcium and Magnesium ions, and sodium ions.

21. Conclusion:
• In conclusion, Sodium is an beneficial element for proper plant
growth and development of certain plant species. It plays a critical
role in soil structure, water movement, osmotic regulation, Ion
balance, and stomatal regulation. However, high levels of sodium in
the soil can lead to salinity, which can be harmful to plant growth.
Therefore, it is essential to maintain proper levels of sodium in the
soil to ensure optimal plant growth and health.

22. References:
Metabolic functions of Sodium in Plants by Amit Bhatnagar.
Unavailability of water in sodic soils
What is the Sodium Absorption Ratio?

23. “A Nation that destroys its soil, destroy itself”
Thank You