Mangoes in India . . . .
PORPAGATION
:
Inarching,
Veneer grafting,
Budding, Stone Epicotyl grafting, Soft-wood grafting, Air layering
PLANTING:
Time
of planting, Planting distance, Size of pits, Filling of pits, Planting
of grafts,
Training
and pruning
FERTILIZERS:
Quantity
of fertilizer, Time of fertilizer application, Method of fertilizer application
IRRIGATION,
INTERCULTURE,
INTERCROPPING
REJUVENATION OF MANGO
ORCHARD
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PROPAGATION
Mangoes are raised
from seed or propagated vegetatively. Propagation from seed, though easy
and cheap, is unable to perpetuate characters of the parent tree because
most commercial varieties in India are cross-pollinated and monoembryonic.
Plants also take more time to bear fruit. Accordingly, several methods
of vegetative propagation have been tried with varying degree of success.
However, it is essential to raise seedlings to be used as rootstocks. For
this purpose, stones should be sown in June-July in beds mixed with well
decomposed farm yard manure at the rate of 8-10 tonnes per hectare. Alternatively,
25 kg nitrogen (N) per ha may be applied in the form of urea, CAN or any
other available inorganic source in two split doses at about two months
interval after the leaves have become green. When the seedlings attain
the age of 2-3 months, they should be transplanted well in prepared beds
or pots one transplanting should be given in well prepared beds or pots.
In this season, proper care should be exercised in irrigating the young
transplanted seedlings. The seedlings should also be protected from frost
by putting the pots under big trees or thatching the young seedlings in
the field.
Plants are generally
propagated using random seedling rootstocks. The polyembryonic rootstocks,
however, have shown a promise in producing plants of uniform size and vigour.
Moreover, these rootstocks have indicated possibility of inducing dwarfing
and earlier bearing and are under test. Various methods employed in vegetative
propagation of mango are described below :
a) Inarching
: The method of inarching or approach grafting is quite cumbersome and
time consuming, but it is still the leading method for commercial propagation
of mango plants. The method consists of uniting the selected shoot (scion)
of a desired parent tree (mother plant) with the potted or transplanted
seedling (rootstock) by approach grafting. For this purpose, about one-year-old
seedlings are most suitable when they attain a height of about 30-45 cm
and thickness ranging from 0.75 to 1.5 cm. These seedlings are either grown
in pots or under the mother plant from which the grafts are to be prepared,
depending upon the availability of suitable branches. Generally, a one-year-old
twig of the scion tree about 60 cm in length and nearly of the same thickness
as that of the stock is chosen for grafting. Young and non-bearing trees
should not be selected as mother plants.
Inarching should be done during
the growing period when the tree is in active sap flow condition termed
as active growth period. A hot and very dry period, as well as heavy rainfall
during the inarching period is not suitable. The end of the monsoon in
heavy rainfall areas and early monsoon in the light rainfall areas is the
best period for inarching. In north India, July is the best month for inarching.
In the more equitable climate of south India, the operation can be done
any time between July and February.
A thin slice of bark and wood,
about 5 cm in length, 7.5 mm width and 2 mm deep, is removed by means of
a sharp grafting knife from the stem of the stock as well as from the scion
branch. The dimensions can be proportionately increased or decreased according
to the thickness of the stock and scion. The cuts thus made should be absolutely
flat, clean, boat shaped, even and smooth. The ends of these cuts should
be round and not angular. The cut surfaces of both, i.e., stock
and scion are made to coincide facing each other so that there remains
no hollow space between the two. These are then tightly tied by polythene
/ alkathene strips of about 1.5 cm in width and preferably of 200 gauge
thickness, which has proved to be a good tying material.
After about one month of operation,
the scion below the graft union and stock above the graft union should
be given light ‘V’ shape cuts at weekly intervals such that grafts can
finally be detached while giving the fourth cut. In the last stage, the
top of the stock above graft union should also be removed completely.
b) Veneer
grafting : This method of propagation possesses promise for mass
scale commercial propagation. The method is simple and can be adopted with
success. The rootstocks as mentioned, for inarching are suitable for this
method also. For conducting this grafting operation, a downward and inward
30-40 mm long cut is made in the smooth area of the stock at a height of
about 20 cm. At the base of cut, a small shorter cut is given to intersect
the first so as to remove the piece of wood and bark. The scion stick is
given a long slanting cut on one side and a small short cut on the other
so as to match the cuts of the stock. The scion is inserted in the stock
so that the cambium layers come on the longer side. The graft union is
then tied with polythene strip as recommended for inarching. After the
scion takes and remains green for more than 10 days the rootstock should
be clipped in stages.
The scion wood to be used
for veneer grafting requires proper preparation. The desired shoots should
be defoliated at least one week prior to grafting so that the dormant buds
in the axis of leaves become swollen. The best time for this method is
the same for different regions as for inarching.
c) Budding
: Although success of budding in mango was reported in the beginning of
this century, budding still continues to remain in experimental stage as
far as commercial mango propagation is concerned.
d) Stone
Epicotyl grafting : Mango is generally propagated by inarchig and
veneer grafting. These methods are time consuming. Stone epicotyl grafting
is a new technique of mango propagation. This method is simple, cheap and
quick. Fresh mango stones are sown in the nursery beds. After germination,
seedlings with tender stems having coppery leaves are lifted with stones
still attached. The roots and stones are dipped in 0.1 per cent Bavistin
solution for 5 minutes after washing the soil. The seedling stems are headed
back leaving 6-8 cm long stem. A 4-6 cm longitudinal cut is made running
down through the middle of the stem. A wedge shaped cut starting on both
sides is made on the lower part of scion stick. The scion stick should
be 4-6 months old and 10-15 cm long containing plumpy terminal buds. The
scion stick is then inserted in the cleft of the seedlings and tied with
polythene strips. The grafts are then planted in polyethylene bags containing
potting mixture. The bags are then kept in the shade protecting from heavy
rain. When the scion sprouts and the leaves become green, the grafted plants
should be planted in nursery beds. July is the most suitable month for
stone grafting.
e) Soft-wood
grafting : The technique of soft-wood grafting is similar to that
of cleft or wedge grafting. In this case, grafting is done on newly emerged
flush having bronze coloured leaves and stem. This method is useful in
in-situ
grafting. The scion wood to be used should be defoliated 10 days prior
to the frafting and having same thickness as that of terminal shoot. The
graft should be secured firmly using 1.5 cm wide and 4.5 cm long, 200 gauge
polythene strip. July and August are the best months for soft-wood grafting.
f) Air
layering : Air layering can be done successfully in mango using
IBA or NAA 10,000 ppm in lanolin paste. Success up to 50 per cent has also
been obtained by using Seradix-B as root promoter. The air-layers can be
used for permanent planting or for raising uniform rootstocks.
PLANTING
Prior to planting, field should
be deeply ploughed, harrowed and leveled. Pits of proper size should be
dug at appropriate distances and filled by adding sufficient quantity of
farm yard manure. The grafts to be planted should be procured from reliable
nurseries few days before actual transplanting.
a) Time
of planting : The best time for planting all over India is during
the monsoon when there is sufficient moisture in the atmosphere. In the
area, of heavy rainfall, the best time of planting mango is the end of
the rainy season. In tracts where the rainfall is less, the planting can
be done in the early part of the monsoon for better establishment. The
planting should be done in the evening, otherwise if the day turns out
to be unusually hot or dry, the plants may wither due to excessive loss
of water. If the sky is overcast, planting can be done during day time
also.
b) Planting
distance : The planting distance varies according to variety, the
fertility level of the soil and general growth conditions in the area.
Where the growth is excessive, the distance should be 12 x 12 m, but in
the dry zones where the growth is less, it can be regulated to about 10
x 10 m. For high density planting, the distance can be 5 x 3 or 5 x 2.5
or 3 x 2.5 or 2.5 x 2.5 meter.
c) Size
of pits : In locations where the soil is loamy and deep, pits of
0.5 x 0.5 x 0.5 m be dug at desired distances. However, in shallow and
hill soils, the pits should at last be of 1 x 1 x 1 m size.
d) Filling
of pits : The pits should be filled with the original soil mixed
with 50 kg well rotten farm yard manure. In the top two-third portion,
the proportion of the manure and soil may be kept as 1:3. If the soil is
having infestation of white ants, 200-250 g of aldrex or BHC dust may also
be mixed.
In case of stony soils, it
is better to remove all the stones from the excavated material and remaining
soils should be mixed with soil scrapped from the left over area and FYM.
The pits should invariably be filled before the rainy season, so that there
is maximum settling down before the advent of heavy rainfall and much before
planting.
e) Planting
of grafts : The plant with its ball of earth intact should be taken
out of the soil or pot. The plant can then be placed with the help of a
planting board in the centre of the pit by excavating as much soil as necessary
to accommodate the root-ball. The moist soil of the pit is then pressed
all around the root ball to complete the the planting process. A small
basin is then made and the plant is properly watered. The planting should
not be done so deep as to bury the graft-union in the soil or so high as
to expose the upper roots. It is always better to adjust it at the same
height/depth at which it was in the pot or the nursery bed.
f) Training
and pruning : Normally, mango trees require very less or no pruning.
However, the training of the plants in the initial stages is very essential
to give them proper shape. Specially when the graft has branched too low,
the process of training becomes very important. At least 75 cm of the main
stem should be kept free from branching and the first leader / main branch
may be allowed after that. The main branches should be spaced in such a
way that they grow in different directions and are at least 20-25 cm apart,
otherwise there are chances of breakage due to smaller crotch angles and
heavy top.
The branches which exhibit
tendency of crossing and rubbing each other should be removed in the pencil
thickness stage, otherwise they break by rubbing each other at a later
stage and create complications. Secondly, if the centre is closed the fruits
produced are of poor quality having less colouration in the absence of
sufficient sunlight.
By following the above practice
and after giving proper shape to the trees, there will be very less scope
for future pruning except removal of diseased, pest infested or dried shoots
/ wood.
FERTILIZER
REQUIREMENTS
Nutrient uptake in mango is from large
volume of soils. Therefore, it is able to sustain growth even in low fertility
soils. But, its efficient management involves the replenishment of the
nutrients used-up by the tree for its growth and maintenance, harvested
produce and natural losses from soils through leaching and run of. Even
the under-nourished trees can be revived by suitable supplementation of
nutrients through fertilizers. The idea of manuring bearing trees is also
to secure regular fruiting. Recommendations based on very limited research
and also on experience gained by the orchardists are given below.
a) Quantity
of fertilizer : Manuring mango plant starts right from planting
operation in the orchard. First application is made at the time of filling
of the pits (refer item 6 d). Fertilizer application during the first year
of planting may be given as 100 g N, 50 g P2O5 and
100 g K2O per plant.
Above dose should be increased every
year up to 10 years in the multiple of first year’s dose. Accordingly,
a 10-year-old tree should receive 1 kg N, 500 g P2O5 and
1 kg K2O. This dose should be continued to be applied in subsequent
years also. Application of 50 kg well-decomposed organic manure should
be given four yearly to create proper soil physical environment. For trench
application of fertilizers, 400 g each of N and K2O and 200
g of P2O5 per plant should be given.
The application of micronutrients
is not recommended as a routine. Need based supplimentations are essential
when these become limiting factor for production. It is advisable to apply
micronutrients through foliar sprays.
b) Time of fertilizer
application : Fertilizers may be applied in two split doses, one
half immediately after the harvesting of fruits in June / July and the
other half in October, in both young and old orchards, followed by irrigation
if there are no rains. Foliar application of 3 per cent urea in sandy soils
is recommended before flowering.
c) Method of
fertilizer application : First of all, the weeds should be removed
from basins. The mixture of recommended dose of fertilizers should be broadcast
under the canopy of plant leaving about 50 cm from tree trunk in old trees.
The applied fertilizer should be amalgamated well up to the dept of 15
cm soil.
To increase fertilizer use efficiency,
fertilizers should be applied in 25 cm wide and 25-30 cm deep trenches
dug around the tree 2 m away from trunk.
IRRIGATION
Amount and frequency of irrigation
depends upon the type of soil, prevailing climatic conditions, especially
rainfall to be given, and its distribution and age of trees. No irrigation
is required during the monsoon months unless there are long spells of drought.
During the first year when the plants are very young with shallow root
system, they should be watered every 2-3 days in the dry season. Trees
in the age group of 2-5 years should be irrigated at 4-5 days interval.
The irrigation interval could be increased to 10-15 days for 5-8 years
old plants during dry season. When trees are in full bearing stage, generally
2-3 irrigations are given after the fruit set. Profuse irrigation during
2-3 months proceeding the flowering season is not advisable. Irrigation
should be given at 50 per cent field capacity.
Generally, intercrops are
grown during the early years of plantation and hence frequency and method
of irrigation has to be adjusted accordingly. It is advisable to irrigate
the mango plants in basins around them which can be connected in series
or to the irrigation channel in the center of rows. The intercrops need
to be irrigated independently as per their specific requirements. In monocropping
of mango also, basin irrigation is preferable with a view to economise
water use.
INTERCULTURE
Interculture in orchards is
necessary for the proper upkeep of mango plantation. The removal of weeds
not only avoids the competition for essential nutrients but also creates
better physical soil environment for plant growth, particularly root development.
It also helps in water movement in soil and in controlling some of the
insect pests. Moreover, it ensures proper incorporation of the applied
plant nutrients in soil and reduces their loss. Frequency and the time
of interculture operations vary with age of the orchards and existence
of intercrops.
Immediately after planting
the mango, the weed problem may not exist, but it is advisable to break
the crust with hand hoe each time after 10-15 irrigations. However, subsequent
hoeing may be done depending on weed growth in the basin. If the intercrops
are not being raised in the pre-bearing stage due to some reasons, the
area between the basins should be ploughed at least three times a year,
i.e.,
pre-monsoon,
post-monsoon and in the last week of November.
Interculture operations are
equally important for the bearing mango orchards. First ploughing should
be done before the onset of rains. This will help in checking run-off losses
and facilitate maximum retention of water in the soil. Orchard may be ploughed
again after the rainy season is over in order to supress weed growth and
to break capillaries. Third ploughing may be done in the last week of November
or first week of December with a view to checking the population of mango
mealy bugs.
INTERCROPPING
Mango orcharding provides
an opportunity for utilizing the land space to its maximum during initial
years (up to 8-10 years) of establishment. Due to wide spacing and developing
root patterns, the large unutilized interspace can be exploited for growing
inter and mixed crops successfully. The soil fertility can also be maintained
/ enhanced by careful selection of intercrops and adequate management of
the orchard. This enables the orchardists to raise extra income during
the years when the main crop yields no / low returns. However, selection
of intercrops depends on agroclimatic region, marketing facilities, levels
of inputs and other local considerations. It is always advisable to avoid
tall growing exhaustive crops like maize, sugarcane, bajara, etc.
Some fertility restoring crops like legumes and leguminous cover crops
should be included into the intercropping patterns. The partial shade loving
crops like pineapple, ginger, turmeric, etc. can be grown in fully
grown orchards. In addition to field crops, some short duration, less exhaustive
and dwarf type inter-fillers like papaya, guava, peach, plum, etc. can
also be grown till these do not interfere with the main mango crop. These
inter-fillers can be selected depending on region and other considerations.
Leguminous crops of like greengram, blackgram, gram; etc., cereals like
wheat; oilseeds like mustard, sesame and groundnut and vegetables crops
such as cabbage, cauliflower, tomato, potato, brinjal, cucumber, pumpkin,
bittergourd, tinda, lady’s finger, etc. and spices like chillies can be
successfully grown as intercrops. Some of important crop rotations recommended
are as follows :
1.Cowpea-potato, 2.Greengram-wheat,
3.Blackgram-wheat, 4. Greengram-gram, 5.Blackgram-gram, 6.Cowpea-wheat,
7.Cowpea-gram
Maximum monetary return can
be obtained from cowpea-potato rotation.
REJUVENATION
OF MANGO ORCHARD
In general, 40-45 years old
mango trees exhibit decline in fruit yield because of dense and overcrowded
canopy. The trees do not get proper sunlight resulting in decreased production
of shoots. New emerging shoots are weak and are unsuitable for flowering
and fruiting. the population of insects and pests builts up and the incidence
of diseases increases in such orchards. These unproductive trees can be
converted into productive ones by pruning with the technique developed
at the Institute.
Intermingling, diseased and
dead branches are removed. Thereafter undesirable branches of unproductive
trees are marked. At the end of December, these marked branches are beheaded
at 1.5 to 2.0 meter from distal end and the cut portions are pasted with
copper oxychloride solution. During March-April, a number of new shoots
emerge around cut portions of the pruned branches. Only 8 to 10 healthy
and outward growing shoots are retained at proper distance so that a good
frame-work is developed in the following years. These rejuvenated trees
are fertilized with 2.5 kg urea, 3.0 kg single superphosphate and 1.5 kg
muriate of potash per plant. The half dose of fertilizers is applied in
the month of February and the other half at the end of June. the plants
are irrigated at an interval of 15 days especially in the months of April,
May and June for healthy growth of new shoots. In the first week of July
150 kg of compost per tree is also applied. Unwanted emerging new shoots
are regularly removed to maintain the tree canopy and avoiding recrowding
of the branches. It also helps in getting proper rourishment to retained
shoots. After two years of pruning new shoots come into bearing and the
yield of fruit increases gradually. Thus, old and unproductive trees are
convered in to productive ones.
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