Taro corms packed in a 10kg box for sale.
Taro (Colocasia esculenta L) is a fast-growing crop that takes between 6 and 12 months to mature. The leaf, stalk and corm can be eaten; however, the main part marketed is the corm. Large-corm cultivars are grown for the fresh food market in Australia.
Taro is a resilient crop, but radiation, temperature and water availability affect the total yield and the time taken to reach maturity. The following information on taro production is based on field observations, local growers' experience and literature as there has been little taro research in Queensland.
Taro is grown in a range of climatic conditions but appears to do better in wetter regions. The climate of the North Queensland wet tropics suits taro cultivation, as long as adequate irrigation and nutrition are provided. Taro is generally grown as an upland crop in North Queensland. Taro is also grown in southern Queensland, northern New South Wales and the Northern Territory.
Taro can tolerate waterlogged conditions because of its ability to transport oxygen from the leaves to the root. It can be cultivated as an upland crop, or under flooded wetland, as may be found along stream banks.
Taro crops reportedly yield well if the annual average rainfall is at least 1500 mm and is evenly distributed throughout the growing season. For example, much of the upland taro grown in Hawaii is not irrigated, as crops depend on the regular rainfall. Optimum yields are obtained in areas with rainfall exceeding 2500 mm.
Being adapted to high temperatures and humidity, taro performs well between temperatures of 21 °C and 27 °C.
Taro will grow on a wide range of soil types from heavy clay loams to light volcanic soils. However, taro will only yield well when planted in fertile, friable soil that has a high water holding capacity and is rich in organic matter. A slightly acid soil (pH 5.5 to 6.5) with moderate clay content is ideal.
Permanently moist soils appear to be most desirable to maximise growth and yield. Moisture stress can be detrimental to growth and supplementary irrigation may be necessary during dry periods.
Establishing and maintaining taro crops
Land preparation and propagation
Land preparation includes weed removal and cultivation to ensure a friable soil texture. Deep rip to improve root penetration if the soil is compacted. Mounding is recommended on the wet tropical coast of North Queensland and in areas where waterlogging or ponding may occur.
As flowering and seed production rarely occurs, taro is propagated vegetatively by setts, which consist of the lower 30-40 cm of the leaf stalk together with the top 1-3 cm of sucker corms or full corms. Healthy and vigorous medium to large setts from the mother plant generally yield higher than small setts. The larger setts also appear to grow faster and hence give better weed control. Setts should be clean, not discoloured or blackened, and free from mould and soft spots.
Planting and harvesting can occur at any time of year in response to consumer demand; however, with a defined alternation of dry and wet seasons, planting is generally done at or shortly before the beginning of the wet season.
Taro may be planted in twin rows, single rows or in plots. Planting holes should be larger than the size of the corm, usually 10-20 cm depending on the size of the sett. Other options are to prepare ridges or furrows, or practise flat planting. Shallow planting will result in corms developing above the ground surface and these exposed corms are more likely to be damaged by insect pests and rodents. Water crops soon after planting to remove air pockets.
Growers generally plant one to three plants per square metre, a planting density of around 10,000 to 45,000 plants per hectare. Higher density produces more, but smaller, corms (anywhere from about 1500 g down to 400 g) and average yield per plant or per hill is reduced. Single row spacings may vary from 60 cm between rows and 50 cm between plants to 160 cm between rows and 60 cm between plants. Twin rows may vary from 80 cm between rows (centre to centre) with 30 cm between the twin row and 20 cm between plants to 2.6 m between rows (centre to centre) with 60 cm between the twin rows and 50 cm between plants. Single row spacing of 90 cm x 60 cm is common, a slightly wider spacing may be used where cloud cover is frequent and growing conditions not optimum. Very wide spacing is not recommended as it provides opportunity for weed growth.
Taro is one of a few crop species that can adapt to a range of moisture regimes. Overwatering is not harmful to its growth, but supplementary irrigation is essential during the dry season. Growth will be restricted and suckering and/or reduced quality may occur if plants are water stressed.
Water can be applied to taro by sprinkler, furrow or drip irrigation, however the ideal amounts are not known for North Queensland.
Fertilised taro has performed and yielded better than unfertilised plots, showing improved corm size and number. Experiments in Hawaii have shown responses to regular applications of nitrogen (N), phosphorus (P) and potassium (K) fertilisers.
Nitrogen appears to be the main requirement. Taro also has a high requirement for potassium, which is essential for starch formation. Liming may be necessary in acid soils. Applications of fertiliser, especially nitrogen, made after the full canopy has formed may affect the eating quality and palatability of the corm.
Mulching is beneficial, provided the soil is not too high in organic matter already. As mulch breaks down, it improves growth rates by providing nutrients and improving soil structure and moisture.
Harvesting and marketing taro
Taro is harvested when the corm reaches the desired size. Crop duration for the varieties grown in North Queensland ranges from 7 to 12 months depending on its management. At maturity, the leaves begin to turn yellow and the new petioles are shorter. The main corms begin to push out of the soil surface, which usually indicates that the crop should be harvested soon.
Harvesting is laborious, the main corms and secondary suckers are broken and loosened from the soil manually. The corms are then pulled out by hand, washed to remove roots and soil and placed in bins for grading and packing. The skin is resistant to mechanical damage during handling.
Yields vary from 4 to 30 t/ha. Yields up to 70 t/ha have been recorded in Hawaii with heavy fertilisation. Commonly yields of 10 – 25 t/ha are achieved.
Grading and storage
Corms are graded according to size or weight, depending on the market. The preferred corm weight is 1 to 1.5 kg, depending on the variety. The cut flesh should look and smell fresh and juicy, only pack quality corms with no rot or other blemishes. Buyers look for firm corms.
Taro does not store well under ambient temperature and should be consumed within two weeks. Refrigeration appears to extend storage life. Shelf life may be extended by marketing the corms with 5 cm green top.
In Australia, taro is sold mainly through specialty agents in Sydney, Melbourne and Brisbane with some direct sales to retailers. Taro prices on the wholesale market are generally around $3 to $4 per kilogram. Corm weights of around 1 to 1.5 kg are desirable, although there appears to be an increasing preference for smaller taro.
There is a potential small corm (Jap taro) market in Japan; however, this market is yet to be tested. Due to insufficient production data and a firm idea of market prices, the economics for taro production is not established.
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- Carmichael, A. et al (2008) TaroPest - An illustrated guide to pests and diseases of taro in the South Pacific. ACIAR monograph # 132
- Daniells, J.W., Hughes, M., Traynor, M., Vawdrey, L. and Astridge, D. (2008) Taro Industry Development: The First Step. RIRDC Publication no 09/066.
- Daniells, J. W., Petiniaud, P. and Salleras, P. (2004) Taro. In 'The new crop industries handbook' eds. S. Salvin, M. Bourke and T. Byrne. RIRDC Publication No 04/125. pp 90-97.
- Hughes, M.J., Daniells, J.W., Vawdrey, L.L., Astridge, D.A. and Traynor, M. (2008) Australian taro industry: benchmark survey. Queensland DPI&F PR08-3392. 57pp.
- Lambert, M (ed.) 1982, Taro cultivation in the South Pacific, South Pacific Commission, Noumea, New Caledonia.
- Purseglove, JW 1972, Tropical crops. Monocotyledons 1, Longman Group Limited.