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Planting and management of plantation
Plant seedlings, air layers or softwood grafts in pits of size 50 x 50 cm during
June-July.
Planting may be done at a spacing of 7.5 m for poor and 10 m for rich and deep soils
and sandy coastal area. On very sloppy lands, the rows may be spaced 10-15 m apart
with a spacing of 6-8 m between trees in a row.
Depending upon the weed growth, weeding operation may be done during August-September.
Mulch the plant base with dry leaves to reduce sun-scorch to tender plants.
Herbicides can be used for controlling weeds. Apply glyphosate 0.8 kg/ha, once in
June-July.
Initial training / shape pruning
The sprouts coming from the rootstock portion of the graft that is from the portion
below the graft joint should be removed frequently during the first year of planting.
Initial training and pruning of young cashew plants during the first 3-4 years is
essential for providing proper shape. Thereafter, little or no pruning is necessary.
The plants should be allowed to grow by maintaining a single stem up to 0.75-1.00
m from ground level. This can be achieved by removing the side shoots or side branches
gradually as the plants start growing from the second year of planting. Weak and
criss-cross branches can also be removed. Branches growing unwieldy may also be
cut off. Proper staking of the plants is required to avoid lodging due to wind during
the initial years of planting. Initial training and pruning of cashew plants facilitate
easy cultural operations such as terrace making, weeding, fertilizer application,
nut collection and plant protection. The flower panicles emerging from the grafts
during the first and second year of planting should also be removed (deblossoming)
in order to allow the plant to put up good vegetative growth. The plants are allowed
to flower and fruit only from the third year onwards.
General pruning
In older cashew plantations, removal of dried or dead wood, criss-cross branches,
water shoots etc. should be attended to at least once in 2-3 years. This allows
proper growth of the canopy and receipt of adequate sunlight on all the branches.
Pruning of cashew plants should be done during May / June.
Manuring
A fertilizer dose of 750 g N, 325 g P2O5 and 750 g K2O
per plant is recommended for cashew. Apply 1/5th dose after the completion
of first year, 2/5th dose during second year and thus reaching full dose
from 5th year onwards. Broadcast the fertilizer within an area of 0.5
to 3.0 m (15 cm deep) around the tree and incorporate by light raking.
Intercropping
Pineapple is the most profitable intercrop in cashew plantation in the early stages
of growth. It can be planted between two rows of cashew in trenches opened across
the slope. Paired row of pineapple suckers can be planted in each trench at 60 cm
between rows and 40 cm between two suckers with in the row. These trenches can be
opened at 1 m between two rows of cashew. Ginger, lemongrass and tapioca are also
suitable as intercrops.
High density planting
High density planting is a recent technique recommended for enhancing the productivity
of cashew plantations. This technique involves planting more number of grafts per
unit area and thinning at later stages. Instead of the normal planting density of
64 to 177 plants per hectare (spacing ranging from 7.5 to 10 m in the square system
of planting) or 74 to 204 plants (spacing ranging from 7.5 to 10 m in the triangular
system of planting), 312 to 625 grafts will be planted per hectare, initially. During
later years, as the canopy develops, plant population is to be regulated by selective
felling to minimize competition.
While adopting a high density planting technique, grafts may be planted initially
at a spacing of 4 x 4 or 8 x 4 m so that there will be 625 or 312 plants respectively.
This population can be retained for a period of seven to nine or ten years depending
upon the canopy expansion rate. If the soil is very rich the canopy development
rate will be faster. High density planting would be more useful in poor soils where
the rate of canopy expansion is slow. Considering the fertility status of the soil,
the level of management in terms of fertilization, irrigation etc. the initial plant
population is to be decided carefully for every agro-climatic condition. Later,
after monitoring the canopy pressure between adjacent plants, the alternate plants
are to be removed. Finally, when the plants attain full growth, the spacing between
the plants will be 8 x 8 m.
If uniform management practices are adopted, during early years of yield, the per
tree nut yield will be more or less the same with all the trees, in both the conventional
system of planting and in high density planting. But the per hectare yield will
be more from high-density plantations (due to higher plant populations) compared
to the normal density plantations. During later years, when the plant population
is equalized to that of normal density plantation, the productivity of both the
plantations would be more or less the same. The bonus yield obtained during the
early years of yield would be substantial in high-density plantations.
In addition to obtaining higher yields, substantial quantities of firewood can be
obtained during thinning, which may fetch additional revenue to the farmer. The
weed growth in the interspace can be effectively checked to a greater extent.
Top working
Top working is a technique evolved to rejuvenate unproductive and senile cashew
trees. Top working can successfully rejuvenate poor yielders in the age group of
5-20 years. The unproductive trees are to be beheaded at a height of 0.75 to 1.00
m from ground level. The stem should be cut with a saw to avoid stump splitting.
The best season for beheading trees is May-September. Soon after beheading, the
stumps and cut portions should be given a swabbing with copper oxychloride and carbaryl
50 WP (50 g each per litre of water). Sprouts emerge 30-45 days after beheading.
Sprouting will be profuse in young trees. New, 20-25 days old shoots should be grafted
with scions of high yielding varieties using softwood grafting technique. To ensure
at least six or seven successful grafts, 10-15 grafting are to be done on the new
shoots of every tree. The best season for grafting is July-November. Thinning of
the extra shoots arising from the stumps should be done to obtain better growth
of the grafts. Removal of sprouts below the graft joint and removal of polythene
strip from the graft joint should be done. Top working is simple and can be done
by farmers after getting proper training.
The top worked trees start yielding right from the second year after top working.
Thus precocity can be considered as one of the best advantages of this technique.
The major disadvantage associated with top working is the huge casualty of trees
due to stem borer attack. Intensive care and management to ward off stem borer is
essential. As such, adoption of top working on a larger scale would be difficult.
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