plant nutrition

2. CROP NUTRIENTS
Introduction ,history, Primary and secondary
nutrients

3. • The nutrients are chemical elements which are absorbed
by the plants in more or less quantity to transform light
energy into chemical energy and to keep up plant
metabolism for the synthesis of organic materials.
• Feeding of plants with nutrients is termed as nutrition.
• Growth and production of the plants are governed largely
by the nutrition.

4. Why is Mineral Nutrition Important?
• In most natural soils, the availability of mineral nutrients
limits plant growth and primary productivity.
• Nutrient limitation is an important selective pressure and
plant face many special changes related to the need to
acquire and use mineral nutrients efficiently.
• “Plant nutrition” specifically does not refer to
photosynthesis.

5. History
• In the early 18th
century van Helmond and woodward
conducted experiments, and demonstrated that;
• C and O form air and water lead to the formation of plant
matter
• Growth of plant is dependent on some peculiar terrestrial
matter.

6. History
• Justus Von
Liebeg(1840) proposed
the ‘Law of Minimum’

7. History
• De Sausssure (1800) worked on the variability in ash (dry
matter) of plants grown in different soils, and suggested
that some elements were universally present in all plants
while others were not.
• Justus Von Liebeg (1840) arrived at the conclusion that
carbon, hydrogen and oxygen were supplied from air
while potassium and phosphorus from soil.
• He proposed “law of Minimum” according to which
growth of a plant is not dependent on the one nutrient
which is present in the minimal quantity.

8. ESSENTIAL ELEMENT
• An element required
by plants for normal
growth, development
and completion of its
life cycle, and which
cannot be substituted
by other chemical
compounds.
• Classified based on
quantity required:
• Macro nutrients
(>100mg/kg of dry
weight)
• Micro nutrients
(<100mg/kg of dry
weight)
• Both are equally
important.

9. SOIL NUTRIENTS
MACRONUTRIENTS
• Nitrogen
• Phosphorous
• Potassium
• Calcium
• Magnesium
• Sulphur
NON MINERAL ELEMENTS
• Carbon
• Hydrogen
• Oxygen
MICRONUTRIENTS
• Manganese
• Copper
• Zinc
• Molybdenum
• Boron
• Chlorine
• Iron

11. Criteria of essentiality
• Proposed by Arnon and Stout (1939).
• An element is considered as essential-
When plants cannot complete vegetative or reproductive
stage of life.
When this deficiency can be corrected or prevented only
by supplying this elements.
When this element is directly involved in the metabolism
of the plant.

12. Nutrient requirements
Nutrients are required for plant processes to function
1) Transpiration - It is a process by which moisture is
carried through plants from roots to small pores on the
underside of leaves, where it changes to vapour and is
released to the atmosphere.
2) Respiration – It is the opposite of photosynthesis, which is
a biological process performed by a green plants that
creates oxygen and releases it into the air. during respiration
plants absorb free molecules of oxygen and use them to
create water, co2 and energy,

13. 3) Photosynthesis – it is process used by plants and other
other organisms to convert light energy into chemical
energy
During this process in green plants, light energy is captured
and used to convert water , co2,and minerals into oxygen
and energy rich organic compounds.

14. Nutrient Loss
• Nutrients are lost in many ways -
Depleted by plants
Used by micro organisms
Leached because of watering
Conversion to gaseous form

15. Root absorption takes place as
• Active absorption
takes place as an
exchange phenomena
and requires energy.
Most plant nutrients
are absorbed in this
manner.
• Passive absorption is a
part of the transpiration
cycle (mass flow).
Water and some
dissolved solutes are
absorbed by this
process.

16. • In the passive part, the movement of low-molecular-
weight solutes (e.g. mostly ions, organic (amino)
acids, sugars) from the external solution into the cell
walls of roots. This process is driven by diffusion or
mass flow.
• In the active part ion uptake takes place due to the
movement of ions from the soil solution into the
plant root against a concentration gradient. This is
followed by the solute transport across membranes.

17. Gas exchange
• Gas exchange take place through the stomata found in
leaves. Carbon dioxide required for photosynthesis and
oxygen required for plant respiration are exchanged
through leaves.

18. Uptake of nutrients in plants
• Mineral uptake is the process in which minerals enter the
cellular material, typically following the same pathway as
water.
• The most normal entrance portal for mineral uptake is
through plant roots.
• During transport throughout the plant, minerals can exit
xylem and enter the cell that require them.
• Mineral ions cross plasma membranes by a chemiosmatic
mechanism.
• Plant absorb mineral as in ionic form; nitrate, phosphate
and potassium ions, all have difficulty crossing a charged
plasma membrane.

20. Forms of nutrients absorbed by plants:

21. Mechanisms of nutrient uptake
• Prior to absorption, nutrients reach the root by 3
mechanisms;
• Mass flow – movement with the water flow. Most
prominent.
• Diffusion – movement in response to a concentration
gradient. Slow process.
• Root interception – root extension. Very important to find
new nutrient sources.

23. BASED ON TRANSPORT:
MOBILE NUTRIENTS- Can be translocated within plants
from older to actively growing tissues.
• Deficiency symptoms appear in older growth.
• N, P, K, Mg.
IMMOBILE NUTRIENTS- Cannot be translocated within
the plant.
• Deficiency symptoms occur in the new growth.
• Ca, S, B, FE, Zn, Cu, Mn.

24. Several terms namely,
• Deficient,
• Insufficient,
• Toxic and
• Excessive are commonly used to describe levels of
nutrient elements in plants.

25. Deficiency of an element
• Deficiency will result in the decrease in normal growth of
the plants, affect the crop yield and produce more or less
distinct deficiency symptoms.
• Typical deficiency symptoms are not often clearly defined.
Masking effects due to the other nutrients, secondary
cause like disease, herbicide toxicity or insect infestation
can confuse field diagnosis.

26. Insufficient levels
• When the level of an essential plant nutrient is below the
required amount for optimum yields or when there is a
imbalance with other nutrients it is considered insufficient.
• The symptoms of this condition are seldom clearly visible,
resulting poor yield.

27. Toxicity levels
• Toxicity level will often cause nutrient imbalances and will
result in poor plant growth, delayed maturity, stunted and
spindly growth and also show visible symptoms of
chlorosis or necrosis.

28. Excessive
when the concentration of an essential plant nutrient is
sufficiently high to result in a corresponding shortage of
another nutrient.

31. REFERENCES:
• A Handbook of Soil Fertilizer and Manure by P. K.
Gupta.
• Crop Nutrition- Principles and Practices by Rajendra
Prasad.
• Nutrient Management in Fruit crops by Dr. B. S.
Chundawat

32. HEALTHY SOIL, HEALTHY PLANT