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Alpinia calcarata (galangal) is also known as rasna in Sanskrit,
kulainjan in Hindi and chittaratha in Malayalam. It is a perennial
herb with non-tuberous pungent rootstock. It grows to a height of 1.5 m and produces
around 24 suckers per clump per year. The economic part is rhizome, which is a major
constituent of many formulations of indigenous system of medicine for relieving
throat inflammation, stimulating digestion, purifying blood, improving voice and
marinating youthful vigour.
Climate and soil
Alpinia comes up well in tropical climate. It grows on a wide range of
climate and soil. Well-drained hilly areas and places up to 1400 m altitude are
good for its cultivation. Fertile red loams to forests soils are suitable.
Propagation
It is propagated vegetatively by rhizomes and by tissue culture methods.
Varieties
At present, only local types are available for cultivation.
Season
Rainfed crop is planted with the onset of monsoon in May-June. Irrigated crop can
be planted at any time.
Land preparation
Plough the field to good tilth. Remove all pebbles and stones. Incorporate FYM or
organic manure at 10-15 t/ha. Prepare raised beds of convenient length and breadth
to facilitate drainage.
Seed rate
Fresh healthy disease-free rhizome bits with at least one shoot is the planting
material, which is required @ 1000-1500 kg/ha.
Planting
Take small pits on the seedbed and plant 5 cm long rhizome bits. Cover rhizome with
FYM and mulch the seedbed with leaves or straw. The optimum spacing is 30 x 20 cm
under poor fertility and 40 x 30 cm under good fertility conditions.
Fertilizer application
Apply fertilizers @ 100:50:50 N:P2O5:K2O kg/ha
per year in two or three split doses. Application of biofertilizer Azospirillum
@ 10 kg/ha and in situ green manuring with cowpea are beneficial for the crop.
Aftercultivation
Carry out gap filling, if required, within one month; remove weeds two months after
planting followed by topdressing, earthing up and mulching. Thereafter no weeding
is required as the crop smothers the weeds.
Plant protection
Usually pests and diseases are not serious enough to take up any control measures.
Occasionally shoot borers and leaf eating caterpillars are observed. Blight disease
can be controlled by spraying 1% Bordeaux mixture.
Harvesting and yield
Though the crop can be harvested after 18 months, the optimum stage of harvest for
obtaining maximum rhizome and oil yield is 36-42 months after planting. Cut and
remove the shoot portion and carefully dig out the rhizomes and roots. Harvesting
is very arduous due to strong and extensive root ramification. Separate the roots,
clean the rhizomes and cut into 5 cm long pieces, which are dried in the sun for
3-5 days to 10% moisture for marketing. The average yield of rhizomes is about 23
t/ha, which on drying gives 25% recovery.
Processing
The fresh rhizomes on steam distillation for 3-5 hours give 0.22% essential oil.
The oil recovery on dry weight basis is 0.93%. Root is also a significant contributor
of essential oil.
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