Citrus is a nutrient-loving plant and need adequate
nutrients for better productivity. The young trees
are usually fed with higher doses of N to make
the tree more productive by inducing more vegetative
growth. In general the nutritional requirements
of mandarin, sweet orange and lime are as follows
|
Age of Plant
|
Recommended Dose of
Fertilizers/Plant/Year
|
|
(Years)
|
FYM (kg)
|
N (g)
|
P (g)
|
K (g)
|
|
1
|
5
|
120
|
60
|
60
|
|
2
|
10
|
240
|
120
|
60
|
|
3
|
15
|
360
|
180
|
100
|
|
4
|
20
|
480
|
240
|
300
|
|
5
|
25
|
600
|
300
|
400
|
|
6-9
|
50
|
720-1000
|
360-500
|
400
|
|
10 and above
|
30-50
|
1000
|
500
|
400
|
Farmyard manure along with 1/3 nitrogen and entire
phosphorus and potash is applied in the month
of June. The balance nitrogen is given in two
split doses in the month of October and February.
The fertilizer should be applied in a ring at
a distance of 60 cm from the main stem. However,
the fertilizer schedule varies with species, age
of the plant and the soil nutrient status.
As soon as visual deficiency symptoms are seen,
remedial measures must be taken immediately for
the correction of the deficiency. Foliar sprays
of organic salts of micronutrients should be sprayed
in case of acute deficiency. The important micronutrient
deficiencies in citrus and their control are given
below.
|
Element
|
Deficiency Symptom
|
Quantity
|
|
Foliar(%) application
|
Soil application
|
| Zinc |
Terminal leaves show yellow blotches in
between veins while the green colour persists
along the midrib and lateral veins. Leaves
are small, narrow, pointed and chlorotic.
Affected twigs are erect, bushy. Chlorotic
leaves drop off-early leading to die back
of twigs. The tree gets stunted. Fruits are
small, malformed and insipid. |
0.5-1.2 Zinc sulphate |
Zinc sulphate @ 500 g/tree |
| Iron |
Deficiency results in network of green veins
against light green or yellow background.
In extreme cases, entire leaf becomes chlorotic.
Reduction on fruit size may occur. This is
a problem in alkaline soils |
0.5-0.9 Ferrous Sulphate |
FeEDTA @ 20g/plant (acidic soils)
Fe EDTA @ 50 g/ plant (alkaline soils) |
| Manganese |
The characteristic symptoms of deficiency
are the green midribs and veins with green
bands and light green interveinal areas. The
leaf size is not reduced. Symptoms are more
prominently seen in the shady side of the
tree. Pronounced leaf symptoms are seen on
mature leaves. |
0.2-0.5 Manganese sulphate |
Manganese sulphate @ 5-10 kg/ha
|
| Copper |
A deficiency of copper results in dark green
leaves borne on S-Shaped twigs. Dieback of
twigs is observed. Slits occur on the bark
through which gum exudes. Fruits show gum
pockets around central pith. Gum exudation
can be seen on the rind also. |
0.5-0.9 Copper sulphate |
Copper sulphate @ 2.5-5.4 kg/ha
|
| Boron |
Trees produce distorted leaves. Mature leaves
show corking or splitting of veins and midrib.
Leaves are twisted. Fruits tend to be hard
and malformed. Brown gum pockets are found
embedding in the juice sacs. |
0.2-0.4 Boric acid |
Borax @ 200 g/plant or 10 kg/ha
|
| Molybdenum |
Deficiency causes yellow spots on leaves.
These spots initially appear as water soaked
areas, which gradually develop into yellow
spots. Gum formation occurs on the underside
of the leaf. In severe cases, defoliation
occurs. |
0.2 Sodium molybdate |
-
|
In general, foliar sprays are applied when young
leaves grow half to two thirds of normal size
in different species. The sprays can be done during
March-April or August-September in north India
or in March-April in south India. Normally, 2
sprays at 15 days intervals are recommended while
in acute cases, 3 sprays can be given. Soil application
should be done in circular bands (50 cm) at 50-75
cm away from the trunk. Combined foliar sprays
are generally recommended when severe deficiency
symptoms are noticed.
