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Senna | Cassia Angustifolia | Cultivation
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Soil & climate | Land Preparation | Nursery Raising &
Planting
Weeding and Manuring | Irrigation| Harvesting & Post
Harvesting
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Soil and
Climate
The crop can thrive on a variety of soils, but is
largely grown on red loams, on alluvial loams. The
texture of the soil which account for the major
hectarage under Senna crop varies from sandy loam to
loam, while the black cotton soils are heavier and
more fertile. The average pH ranges from 7 to 8.5. It
is very sensitive to water logging. Hence, grown only
on well-drained soils.
Senna is a warmth-loving crop and required bright
sunshine for its successful growth. It can be grown in
early summer (February–March) or in winter
(October–November) crop. Whereas under North Indian
conditions like Delhi and Gujarat, where the rainy
season is short, it is reported to be the ideal time
as the plants put on luxuriant growth and give the
maximum growth. Heavy rains and cloudy weather during
growth are harmful to the crop. An average rainfall of
25-40 cm. distributed from June to October is
sufficient to produce good crop.
Land
Preparation
The land is ploughed deep and the soil is exposed to
sun for 110-115 days to dry out roots of perennial
weeds followed by two cross ploughing harrowing and
levelling. Farm-yard-manure (FYM) is incorporated into
the soil at the time of final cross ploughing. Then
the land is laid out into plots of convenient size
with irrigation channels.
Nursery Raising and Planting
Seeds raise the crop. The seeds have hard and tough
seed coat. Soaking seeds for 10-12 hours before sowing
was reported not only to give 100 percent germination.
About 20 kg of seeds are required to cover a hectare
of land.
The seeds are broadcasted or preferably sown at 30 cm
lines to 30 cm apart and 1.5 to 2.5 cm depth in a
well-prepared land. Germination commences on third
days and completed within a fortnight. Before sowing
the seeds, the field should be perfectly levelled
otherwise it hampers the uniform seed germination. It
is found that the seed treatment with Thiram, Captain
or Agroson G.N. at 2.5 g/kg protect the seedlings from
damping off and seedling blight diseases which are
very common.
Weeding and Manuring
The first weeding cum hoeing is done at 25-30 days of
sowing and second at 75-80 days and third at 110 days
to keep the crop free from weeks. Use of Teeflan
herbicide as pre-emergent spray at the rate of 4
kg/hectare has been reported to increase the yield and
Anthraquinone content.
4-5 cart loads (5-10 tones) of well rotten FYM per
hectare is required. In general, where specific soil
nutrient status of the field is not readily found, 80
kg each of P2O5and K2O may be applied per hectare for
the higher production of leaf, pod and total
alkaloids. of these, entire dose of Phosphorus and
Potassium and 50 per cent of Nitrogen has to be
applied at 90 days after sowing.
Irrigation
Senna could be economically grown under rainfed
conditions. In most years, the crop needs no
irrigations except under the conditions of prolonged
drought. However, when it is grown as a semi-irrigated
crop, the yield increased considerably. About 5-8
light irrigations are enough to raise a good crop of
Senna, however, heavy irrigations are injurious to the
crop.
Harvesting
& Post Harvesting
Senna plant produces foliage containing higher
sennosides between 5-90 days age, depending upon the
total plant growth. The picking of leaves is done by
hand so that most of the growing tops are removed at
harvest. This also induces the plants to produce more
of branching which otherwise reduce foliage growth
considerably. A second picking is taken at 90-100 days
and the third picking between 130-150 days when the
entire plants are removed so that the harvested
material includes both leaves and pods together.
The harvested crop should be spread over open field
area in a thin layer to reduce its moisture. Further
drying of produce is done in well-ventilated drying
sheds. It takes 10-12 days to dry completely in
well-ventilated drying sheds. The dried leaves and
pods should have light green to greenish yellow color.
A rapid mechanical drying at 400 C could also be
attempted. The produce is baled under hydraulic
pressure and wrapped in gunny bags, for export or
domestic consumption
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SENNA MAIN
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