Zingiber officinale (Ross)
Halia, halia pedas, alia, halia bara, halia padi, halia hudang, halia nasi, halia cina.
Jahe, aliah, jae, lia, sunti.
|A fully grown clump of ’halia’|
‘Halia’ (Zingiber officinale) which has long been a mainstay in Asian and western cooking, is a very important spice in the global market. ‘Halia’ originated from Southeast Asia and is widely grown throughout the world. India, China, Nigeria, Australia and Thailand are among the countries producing ‘halia’. In Malaysia, ginger is grown on small scale as single crop or sometimes alternated with pineapple, rubber and oil palm.
‘Halia’ is a herbaceous, perennial plant and normally grows to a height of 30-100 cm. The stem extends above ground with long, narrow, ribbed, green leaves, and purple to brownish flowers. The rhizome is branched and arranged laterally under the soil surface. The flesh is rough and hard. The fibre content, yield and pungency depend on the varieties. The rhizome of ‘halia bentong’ is bigger with dull whitish colour and less fibrous compared to ‘halia tanjung sepat’ which has yellowish, fibrous and slender rhizome.
|The growth habit of ‘halia’|
Medicinal Properties and Usage
‘Halia’ is used as spice for flavouring food and as ingredient of herbal medicines. The plant is categorised as traditional Malay herbs. ‘Halia’ helps to digest food, strengthens the sex desire, increases the semen quantity, and as carminative, stimulant and antibacterial agents. Herbal medicine from ‘halia’ also assists in controlling fever, cough, migraine, toothache, rheumatism, stomach cramps, chest pain and insect bites. Active ingredients in the ‘halia’ are gingerols and oleoresin. ‘Halia’ oil can be used as flavour in fruit cordial, confectionery, cosmetic and medicines. In herbal medicine, ‘halia’ is taken as a drink, dried ‘halia’ boil and ‘halia’ extract. In cooking, fresh, dried and candied ‘halia’ are used.
Soil Suitability and Climatic Requirement
‘Halia’ is adapted to tropical environment and is suitable for growing in many locations in Malaysia. The plant thrives well at 1,500 m above the sea level. The main growing area of ‘halia’ is at Bukit Tinggi, Bentong. The area is about 600-700 m above the sea level with minimum and maximum temperature of 16oC and 28oC, respectively. The total annual rainfall of 2,000-3,000 mm is required for good growth. ‘Halia’ can be planted on various soil types from peat to heavy clay soil. Soil with good drainage is favoured to avoid bacterial wilt disease. ‘Halia’ is very susceptible to waterlogged condition.
Good land preparation is a prerequisite to ensure successful production. For mineral soil, the land has to be ploughed and rotovated 1-2 times. The newly-developed peat soil with pH of 3.6 has to be limed with Ground Magnesium Limestone (GML) at the rate of 7.5 t/ha. On mineral soil normally no lime is required unless the pH is less than 5. Bed is prepared after soil preparation especially for soil with poor drainage. The bed is normally 60-120 cm wide and 25-30 cm high. The distance between each bed is 30-80 cm.
Production of Planting Materials
‘Halia’ is propagated using clean, mature rhizomes of more than 9 months in the field. About 1,500-2,000 kg of fresh rhizomes is required for one hectare of land. Rhizomes have to be kept at cool, wet place to encourage bud formation which takes place 2-3 weeks at storage. Rhizomes are then split cut 5 cm long with 2 buds. About 25-30 cuttings are obtained from 1 kg of rhizomes. The cut rhizome has to be treated with Bordeaux mixture (2 kg copper sulphate, 2 kg lime and 250 litres water) or 1% formalin solution for 5 minutes. The cuttings are dried before planting.
|Germinated rhizome cuttings ready for field planting|
Planting should be done at the onset of rain. The planting distance is 25 cm within a row and 45 cm between rows with 2-3 rows in one bed. The cut rhizome is sown 10 cm deep with the bud upright. Mulching using dried coconut leaves or rice straw should be done 2-4 weeks after planting when newly-developed leaves just appear. This is done until three months to avoid leaf scorch which could lead to leaf spot disease. 
|Field planting of ‘halia’ on peat soil|
‘Halia’ need considerably high nutrient supply. High organic and inorganic fertilisers are needed to ensure good growth. Inorganic compound fertiliser NPK (12:12:17:2+TE) is applied in split of 4-5 times per growing season and the fertiliser is divided equally. Organic fertiliser using chicken manure is applied 3-5 days before planting.
Weed control is done once in 2-3 months. The next weeding is normally done together with hilling. Hilling is actually raising up the soil at the plant base to cover the rhizome from being exposed to sunlight and to encourage growth. Mulching using rice straw or dried coconut leaves helps to control weeds, avoids bed slacken off, controls nutrient loss and maintains soil moisture.
A sufficient water supply is needed for ‘halia’ cultivation. Irrigation is needed during the early growth stage unless it rains.
Pest and Disease Control
Stem borer (Udapes falus) is the main pest of ‘halia’. The borer makes holes in the stem and subsequently leaves will turn yellowish and dried. Stem borer can be controlled using insecticide such as permethrin, acephate or methamidophos. Bacterial wilt is the major disease that could lead to great loss in ‘halia’ production. The disease is caused by Pseudomonas solanacearum, which can remain in the soil for years. The symptom is the yellowing of lower leaves and spreads to the upper leaves. The leaves subsequently become brown, wet, soft and easily detached from the stem. Planting using treated planting materials and alternating the area with other crops can reduce this disease problem.
Harvesting is done for green ‘halia’ or mature ‘halia’ at 4-5 months and 8-9 months respectively, after planting. The best time of harvest is when the plant is at 7-8 months of age. Rhizome harvested after 9 months is fibrous and this lowers the quality. Harvesting is done when the stem becomes brownish. ‘Halia’ has to be harvested carefully using a hoe to avoid bruising the rhizome. The cleaned rhizome has to be kept away from full sunlight to avoid moisture loss and change of colour. The yield of mature ‘halia’ and green ‘halia’ are 15-22 t/ha and 8-12 t/ha respectively.
Rhizome has to be cleaned from dried leaves, stems and soils. The ‘halia’ is placed in bamboo or plastic basket for washing under running water. Care is needed to avoid bruising ‘halia’ during cleaning. To control fungus, rhizome is soaked in Bordeaux mixture (500 ppm) for 15 minutes and left to dry. The cleaned rhizome is kept at room temperature for 4-5 days to allow a protection layer to be formed outside the rhizome.
|Curing of matured ‘halia’ under shade at room temperature|
The estimated cost of production per hectare of ‘halia’ is RM24,720. Based on 15-22 t/ha rhizome yield, the production cost is estimated to be RM1.12-RM1.65/kg. The production cost was estimated based on the cost of current inputs during writing of this article.