Transcript Role and deficiency symptom of secondary nutrients in rice

Role and Deficiency Symptoms of
Secondary Nutrients in Rice
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Introduction
In today’s agriculture with the emphasis on
higher crop yields, there is an increased need
for calcium, magnesium and sulphur, called
secondary nutrients.
Some of the factors
increased need are:
responsible
for
this
Increased use of higher analysis fertilizers.
Increased crop yields.
High crop utilization of calcium, sulphur
and magnesium.
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Introduction
Decreased
use
of
sulphur
insecticides and fungicides
Government restrictions on
emissions to the atmosphere.
containing
sulphur
Many soils are acidic and need limestone,
which provides calcium.
Many soils are deficient in sulphur and
magnesium.
Increased awareness of sulphur
and magnesium needs.
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Sulphur (S): role in rice
It is a constituent of essential amino acids
(cysteine, methionine, and cystine) involved in
chlorophyll production and is thus required for
protein synthesis, and plant function and structure.
Sulphur is also a constituent of coenzymes
required in protein synthesis. It is contained in the
plant hormones thiamine and biotine, both of
which are involved in carbohydrate metabolism.
S is also involved in some oxidation-reduction
reactions.
It is less mobile in the plant than N so that
deficiency tends to appear first on young
leaves. S deficiency affects human nutrition by
causing a reduction in cysteine and methionine
content in rice.
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Sulphur deficiency in rice:
http://www.flickr.com/photos/philrice/3176059128/
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Causes of S deficiency
Low status of S in the soil.
Depletion of soil S as a result of
intensive cropping systems.
Use of S-free fertilizers
S concentrations in groundwater,
however, may range widely.
Irrigation water contains only small
quantities of SO42-.
S contained in organic residues
is lost due to burning.
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Occurrence of S deficiency in soils
Soils containing allophane (e.g., Andisols)
Soils with low organic matter status.
Highly weathered soils containing
large amounts of Fe oxides.
Sandy soils, which are easily leached.
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Corrective measures of S deficiency
S deficiency is easily corrected or prevented by using S-containing
fertilizers (Table 1)
Table 1. Sulphur containing fertilizers for rice
Name
Ammonium sulphate
Formula
(NH4)2SO4
Content
24% S
Single superphosphate Ca(H2PO4)2 . H2O 12% S, 7–9 % P, 13–
+ CaSO4 . 2 H2O 20% Ca
Potassium sulphate
K2SO4
18% S
Comments
Quick-acting
Soluble, quickacting
Quick-acting
Magnesium sulphate
(Epsom salt)
Kieserite
Langbeinite
MgSO4 . 7 H20
MgSO4 . H20
K2SO4 . MgSO4
Very quickacting
23% S, 17% Mg
Quick-acting
18% K, 11% Mg, 22% S Quick-acting
Gypsum
Elemental S
S-coated urea
CaSO4 × 2 H2O
S
CO(NH2)2 + S
17% S
97% S
6–30% S, 30–40% N
13% S, 10% Mg
Slow-acting
Slow-acting
Slow-acting
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Magnesium (Mg): role in rice
Magnesium activates several
enzymes.
It is a constituent of chlorophyll,
and is involved in CO2 assimilation
and protein synthesis.
Mg also regulates cellular pH and
the cation-anion balance.
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Magnesium deficiency symptoms in rice
It is very mobile and is retranslocated easily from
old leaves to young leaves. Deficiency symptoms
therefore tend to occur initially in older leaves.
Mg-deficient plants are pale-coloured with interveinal
chlorosis first appearing on older leaves, and later on
younger leaves as deficiency becomes more severe.
Green coloring appears as a "string of beads"
compared with K deficiency, in which green
and yellow stripes run parallel to the leaf.
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Magnesium deficiency symptoms in rice
Leaf number and leaf length are greater in Mgdeficient plants and Mg-deficient leaves are wavy
and droopy due to an expansion in the angle
between the leaf sheath and leaf blade.
With moderate deficiency, plant height and
tiller number are not affected greatly.
Reduced number of spikelets and reduced
1,000-grain weight. May reduce grain
quality (% milled rice, protein, and starch
content).
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Magnesium deficiency symptoms in rice
Orange-yellow interveinal chlorosis
usually appears first on older leaves
Chlorosis may also
appear on the flag leaf.
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Magnesium deficiency symptoms in rice
Mg deficiency may also be
induced by large applications
of K fertilizer on low Mg status
soils (IRRI, Phillipines)
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Causes and occurrence of Mg deficiency
Important cause of Mg deficiency is low
available soil Mg. Furthermore, decreased Mg
uptake due to a wide ratio of exchangeable
K:Mg (i.e., >1:1) causes its deficiency.
Mg deficiency is more common in rainfed lowland and
upland rice where soil Mg has been depleted because
of the continuous removal of Mg in crop products
without recycling crop residues or replacing removed
Mg with mineral fertilizer. Many rainfed rice soils are
inherently deficient in Mg.
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Corrective measures of Mg deficiency
Apply Mg-containing fertilizers (Table 2). Rapid correction
of Mg deficiency symptoms is achieved by foliar application
of liquid fertilizers containing Mg (e.g., MgCl2).
Table 2. Magnesium containing fertilizers for rice.
Name
Kieserite
Formula
MgSO4 . H20
Content
17% Mg, 23% S
Langbeinite
K2SO4,
MgSO4
MgCl2
18% K, 11% Mg, Quick-acting
22%S
9% Mg
Soluble, quick-acting
MgO
42% Mg
Magnesium
chloride
Magnesium
oxide
Magnesite
Dolomite
MgCO3
MgCO3.
CaCO3
Comments
Soluble, quick-acting
Slow-acting, for foliar
application
25-28% Mg
Slow-acting
13% Mg, 21% Ca Slow-acting, content of
Ca and Mg varying
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Calcium (Ca): role in rice
Calcium is a constituent of Ca pectates, important
cell
wall constituents also involved in
biomembrane maintenance.
Helps in cell wall stabilization as an enzyme
activator, in osmoregulation, and in the cationanion balance.
Ca is less mobile in rice plants than Mg and K. Because
Ca is not retranslocated to new growth, deficiency
symptoms usually appear first on young leaves. Ca
deficiency also results in impaired root function and
may predispose the rice plant to Fe toxicity.
An adequate supply of Ca increases resistance
to diseases such as bacterial leaf blight or brown
spot.
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Calcium deficiency symptoms in rice
Symptoms are usually visible only under severe Ca
deficiency (e.g., pot experiments, exhaustion experiments).
The tips of the youngest leaves become
white or bleached, rolled, and curled.
Necrotic tissue may develop along the lateral
margins of leaves and old leaves eventually turn
brown and die.
Ca deficiency may resemble B deficiency and plant
tissue analysis may be required to distinguish the
cause of symptoms.
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Calcium deficiency symptoms in rice
The tips of the youngest leaves may
become chlorotic-white (IRRI, Phillipines)
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Causes of Ca deficiency
Small amounts of available Ca in soil
(degraded, acid, sandy soils)
Alkaline pH with a wide exchangeable Na:Ca ratio
resulting in reduced Ca uptake. Use of irrigation water
rich in NaHCO3.
Excessive N or K fertilizer application resulting in wide
NH4:Ca or K:Ca ratios and reduced Ca uptake.
Excessive P fertilizer application, which may
depress the availability of Ca (due to formation of
Ca phosphates in alkaline soils).
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Occurrence of Ca deficiency in soils
Acid, strongly leached, low-CEC soils in
uplands and lowlands
Soils derived from serpentine rocks
Coarse-textured sandy soils
percolation rates and leaching
with
high
Leached, old acid sulphate soils with low base
content
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Corrective measures of Ca deficiency
Apply CaCl2 (solid or in solution) or Cacontaining foliar sprays for quick treatment
of severe Ca deficiency.
Apply gypsum on Ca-deficient nonacidic
soils, e.g., on sodic and high-K soils.
Apply lime on acid soils to raise pH and Ca
availability.
Apply Mg or K in conjunction with Ca
because Ca may cause deficiencies in
these nutrients.
Apply pyrites to mitigate the effects of
NaHCO3-rich water on Ca uptake.
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Corrective measures of Ca deficiency
Table 3. Calcium containing fertilizer sources for rice.
Name
Formula
Calcium
chloride
CaCl2
H2O
Gypsum
CaSO4
H2O
Dolomite MgCO3
CaCO3
Lime
CaCO3
Content
..
..
6 18% Ca
2 23%
18% S
Comments
Soluble, quick-acting, does
not raise pH
Ca, Slightly soluble, slow-acting,
for saline and alkaline soils
+ 13%
Mg, Slow acting , content of Ca
21% Ca
and Mg varying
40% Ca
Slow-acting, for acid soils
Role and Deficiency Symptoms of Secondary Nutrients in Rice
Let us sum up
Calcium, magnesium and sulphur are essential for rice crop.
Variety of roles are being played by these
secondary nutrients in rice
Their deficiency under certain situations produces
varying symptoms, which eventually affect the growth
and yielding ability of rice.
The deficiency of sulphur is more common
than deficiency of calcium and magnesium in
rice soils in India.
The deficiency of these nutrients can be corrected
by applying appropriate fertilizers and crop
management practices.