Mineral Nutrition

Picart, Rogelio Jr.

Essential and beneficial elements

“ A mineral element is considered to be essential for plant growth and

development if the element is involved in plant metabolic functions and
the plant cannot complete its life cycle without the element”.
There are seventeen essential elements required for plant growth viz., C,
H, O, N, P, K,Ca, Mg, S, Fe, Mn, Zn, Cu, B, Mo, Cl, Ni,
The following is the essentiality criteria described by Arnon and Stout
(1939)
1. A plant must be unable to complete its life cycle in the absence of the mineral
element.
2. The function of the element must not be replaceable by another mineral
element.
3. The element must be directly involved in plant metabolism.
Essential and beneficial elements

Beneficial Nutrients/Elements:
• mineral elements that stimulate plant growth and exhibit beneficial effects at very
low conc.
• Essential only for certain plant species or under specific conditions
• E.g. Na,Va, Co, Si
D.J.Nicholas coined the term “functional or metabolic nutrient”
• Any mineral element that functions in plant metabolism, whether or not its action
is specific. (Cl, Si, Na,Va, Co, Se)
Classification of essential elements

1) Based on the amount required by the plant

• i) Major nutrients – required in large quantities eg.
N,P,K
• ii) Secondary nutrients – required in lesser quantities
compared to Major nutrients eg. Ca,Mg,S
• iii) Micronutrients- required in trace quantities eg. Fe,
Mn, Zn, Cu, B, Mo
Classification of essential elements

2)Based on mobility in phloem

• Mobile elements : N, K, P, S and Mg
• Immobile elements : Ca, Fe and B
• Intermediate : Zn, Mn, Cu, Mo
Classification of essential elements

3) Based on the role of element in plant system

(functional or metabolic)
a. Structural Elements : C, H, O (framework)
b. Accessory structural elements : N. P. S (protoplasmic)
c. Regulator & Carriers : K, Ca, Mg (Balancing)
d. Catalyst & Activators : Fe, Mn, Zn, Cu, Mo, Cl, B
(Catalytic)
General role of essential elements

• Nutritive role
• Catalytic role
• Balancing role
Diagnostic Procedures
1. Graph between deficiency region to toxicity region
Diagnostic Procedures

Nutrient Deficiency Symptoms in Plants Disadvantage and Limitations:

Principle. Plants express certain symptoms • Does not include whether it is due to soil
associated with a lack of an essential element deficiencies or to the inability o the plant to
or growth factor. absorb, assimilate, and translocate the nutrient
Advantages: element.
Experienced agronomists can identify quickly • Difficulties in identifying the symptoms.
what problem a crop is having and without Chlorosis may be cause by at least 5 elements
analytical work. deficiencies.
• Deficiencies in one element may prevent the
uptake of another element causing the plant to
show deficiency symptoms in both.
• Some nutrient deficiency symptoms resemble
certain disease symptoms or damage.
Diagnostic Procedures
e. A correct identification of a nutrient deficiency does not indicate how
much of the nutrient should be applied to correct that deficiency.
f. Since many symptoms appear only at advance stages of the deficiency,
it may be too late for the farmer to correct it and achieve the full yield
potential of the crop.
Common Foliar Symptoms of Nutrient Deficiencies
• Uniform chlorosis
• Interveinal chlorosis
• Necrotic spots
• Bronzing
• Tip chlorosis or necrosis
Influence of Nutrient mobility on Sypmtomology
 Mobile Nutrients
- deficiency symptoms appear in oldest(lower) leaves first
- nutrient moves to youngest leaf – sink
 Immobile Nutrients
- deficiency symptoms appear in youngest (upper) leaves first
- nutrient becomes part of a plant compound
Nutrient mobility in Plants
 Very mobile
- N, P, K, Mg
- Deficiency symptoms appear first in the older leaves and qucikly spread
throughout the plants
 Moderately mobile
- S, Fe, Cu, Mn, Mo, Zn,
- Deficiency sypmtoms first appear on the new growth but do not
readily translocate to the old growth
 Immobile
- B, Ca
- Very immobile
Keys to Nutrient Deficiency Symptoms in Crops

NUTRIENT COLOR CHANGE IN LOWER LEAVES

N Plant light green, older leaves yellow
P Plants dark green with purple cast,
leaves and plants small
K Yellowing and scorching along the
margin of older leaves
Mg Older leaves have yellow discoloration
between veins-finally reddish purple
from edge inward
Keys to Nutrient Deficiency Symptoms in Crops
Keys to Nutrient Deficiency Symptoms in Crops

NUTRIENT COLOR CHANGE IN UPPER LEAVES

(Terminal bud dies)
Ca Delay in emergence of primary leaves,
terminal buds deteriorate
B Leaves near growing point turn yellow,
growth buds appear as white or light
brown, with dead tissue.
Keys to Nutrient Deficiency Symptoms in Crops
Keys to Nutrient Deficiency Symptoms in Crops

NUTRIENT COLOR CHANGE IN UPPER LEAVES

(Terminal bud remains alive)
Fe Leaves yellow to almost white,
interveinal chlorosis at leaf tip
Mn Leaves yellowish-gray or reddish, gray
with green veins
Cu Young leaves uniformly pale yellow,
may wilt or wither without chlorosis
Mo Wilting of upper leaves, then chlorosis
Keys to Nutrient Deficiency Symptoms in Crops
Keys to Nutrient Deficiency Symptoms in Crops

NUTRIENT COLOR CHANGE IN UPPER LEAVES

(Terminal bud remains alive)
Cl Young leaves wilt and dies along
margin
S Leaves including veins turn pale green
to yellow, first appearance in young
leaves
Zn Interveinal chlorosis in bands on young
leaves; new leaves small, mottled, and
chlorotic; Leaf rosetting
Keys to Nutrient Deficiency Symptoms in Crops