Hybrid castor cultivation
Ricinus communis
Ricinus communis generally known as castor bean and
Amanakku in Tamil , establishes itself easily and can be often found on
wasteland .
Castor seed
is the source of castor oil, which has a wide variety of uses. The seeds
contain between 40% and 60% oil that is
rich in triglycerides , mainly ricinolein. India is the largest producer of
castor followed by china .two seed
sizes are reported in india 1164 seeds / kg and 2610 seeds/kg.
Collection
of fruits
Plants
become reproductive in the first season ( within six months) and are capable of
flowering year round in a frost-free environment .
A single
large plant 10.2 feet (8m) diameter was found to produce 1,50,000 seeds ,while
a smaller plant (1m) diameter produces only 1,500 seeds.
Where castor
were merely collected from wild or naturalized plants, their harvesting
involved picking the clusters , knocking them against Some suitable tree or rock and picking up the
released seeds ,or the clusters would be trodden under a horny foot until
shattered. The fruits either by placing in a sack and struck until hulled, laid on the ground and
beaten with a stick.
Alternatively,
clusters are usually stripped by hand , unshelled seed being taken to a central
depot for hulling . In harvesting of the giant type , clusters were often so
high above the ground that it was necessary to climb the tree to pick them .off
the whole cluster
Long handled
harvesting shears and knives could be used to cut or hand reaping could be
carried out most efficiently by means of a reaping jug , or stripping cup.
On an
average castor produces 4-5 sequential order spikes which can conveniently be
harvested in 3-4 pickings starting from
90-120 days at intervals of 25-30 days. premature harvesting leads to reduced
seed weight , oil content and germinability.
Seed
extraction and processing
Extraction
of seeds: seeds not
mechanically hulled were shelled by spreading the capsules 15 cm deep on a
threshing floor under the sun. within 5-6 days most of the capsules will have
shattered. it is desirable to surround the area with corrugated iron sheets ,as
the seeds shoot out with some force when the hulls shatter.
Harvesting
operations are generally spread over a period of five to ten weeks and between
four to six pickings are necessary. highest yields are obtained where the
clusters are harvested at maturity, tied In bundles and hung to dry but normal
practice is to harvest the crop when a few fruits on each spike ripen
Pre-curing and drying : In southern India
the harvested capsule are placed in heaps over which cow –urine water is
sprinkled to soften the husk and assist shelling .this local practice is to
impart a good colour and gloss to be seed. The treated heaps are covered with
straw and weighted to exclude air . In northern india , capsules may be buried
in pits and covered with dung and earth. This is considered to assist ripening
of immature fruits and facilitate milling.
After four
to ten days the capsules are spread in the sun to dry .
Storage
Castor seed
is very hard and does not require much care during storage. No insect or fungus
attacks the seeds. Under ordinary conditions of storage in jute (gunny ) bags.
The oil and free fatty acid Content of the seeds are not affected even after
three years of storage.
It is
recommended that castor seeds be dried to7-8 % moisture content before storing
.artificial low temperature storage also affects the viability .castor seed
stored at 5-6% reduce the germination from 93 to 3% . during bagging the seeds
, handling should be minimized.
On large
scale handling, wooden scoops, shovels and rubber conveyor belts are
recommended. Seeds should be stored at dry place and cooler part of the house.
Germination
Castor bean
is the tropical plant that has a high photo synthetic capacity with high
humidity. Low temperature strongly inhibits photo synthesis and freezing
temperatures kill seedlings. Shade tends to inhibit germination and produce
smaller, slower- growing plants.
Germination
increases with increased seed weight ,lower moisture content of seed at harvest
,earlier planting date .early harvest after first frost .
Initial
germination has been reported to be 92% .seeds stored ambient temperature lose
7 5% of their viability within three months(cisr,1972). Soaking the seeds for
12 hours prior to sowing is
Reported to
improve germination .germination starts 7 to 10 days and is complete in 25 to
45 days (kadambi and dabral 1955)
Distribution
Castor is
native to Africa and introduced in many tropical and subtropical areas of the
world .
Environmental
requirements
Castor is
reported to tolerate annual precipitation of 200 to 4290mm, annual temperature
of 7.0 to 27.8° C and pH of 4.5 to 8.3,
Grows best
where temperatures are rather high throughout the Season, but seed may fail to
set if it is above 38° C for an extended period .
Plant
requires 140 -180 day growing season , It is frost tender species., high
humidity contributes to the development of diseases.
Plants do
best on fertile , well drained soils Which are neither alkaline nor saline;
sandy and clayey loam is best suited.
Establishment
of plantation
Plough two
–three times with country or mould board plough.spread 12.5 FYM or compost
evenly on the main field before last ploughing and incorporate in to soil by working a country plough. Adopt aseed rate
of 10 kg per ha for a normal varieties. And 5 kg per ha for hybrids. Spacing for long duration crop is 90*90 cm and
for short duration is 60*45 cm.
As an
intercrop , raise one row of castor for every six rows of groundnut. In the
case of late receipt of monsoon , black gram +castor at 6:1 ratio is
recommended.
In India
castor is a dry land crop. Castor exhausts the soil quickly .
Apply NPK
fertilizers basally @ 30:15:15 kg per ha. Where phosphorus is deficient, 40-50
kg per ha of p₂o₅ is recommended.
Hoe and hand
weed on 20th day sowing to remove the weeds and repeat the operation on 40th
day of sowing ,if necessary . castor is rotated with ragi ground nuts ,dry land
chillies, tobacco or horsegram.
Growth and yield :
Observe the crop considering the
average duration of the variety .
(i)
One or more
capsules show sign of drying
(ii)
Cut the matured
racemes without damaging the secondaries.
(iii)
Dry the capsule
in the sun without heaping it in the shade
(iv)
Use castor to
separate the seeds or beat the dried capsule with wooden planks , winnow and
collect the seeds
Average seed yield range from 900-1000 kg per
ha under irrigation,300-400 kg per ha without adequate moisture .
Average Indian yields are 560 kg per ha .oil
content of seeds
Varies from 35 to 55%.
Castor was neglected crop till
recently as the oil and cake had few uses. the oil can be used as fuel and cake
as biofertilizer.
If you sow the castor in your land, you will see
the cash in your hand”
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