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Advice on Publications Available.Contribution from John Bonnardeaux
Agriculture Western Australia
Kununurra, WA 6743.
Further details are given in Miscellaneous Paper 5/94 entitled 'The prospect for an asparagus industry in northern Western Australia' by John Bonnardeaux published by the Department of Agriculture, Western Australia in July 1994.
Asparagus is traditionally grown as a temperate crop but this article and the following article clearly show that it has considerable potential for tropical areas. John Bonnardeaux, of Agriculture Western Australia describes the results of research conducted in the semi-arid tropics of the Ord River Irrigation Area in northern Western Australia. In contrast, Bill Bussell and Mark Bonin describe the results of research conducted at the University of the South Pacific in the humid tropics of Western Samoa. All three authors are enthusiastic about the potential of asparagus as a new vegetable crop for tropical areas.
The bulk of fresh asparagus production in Australia is produced on 2 000 ha south of latitude 25°C between the end of August and December.
Virtually no fresh asparagus is produced in Australia during May, June and July and local demand is met by imports from the USA and Thailand. These annual imports are currently about 100 tonnes of fresh asparagus, having a market value of about $1 million.
The Australian consumption of fresh asparagus is only 0.8 kg/person/year which is small, compared with the consumption of other vegetables, such as cucumbers (1.5 kg/year), celery (2.8 kg/year), carrots (8.8 kg/year) and tomatoes (21 kg/year). Consequently, much of the Australian production of fresh asparagus is exported, with 90% of exports going to Japan.
On the Australian market, prices for asparagus range from $2.00 to $4.00 per kg during the main period of supply, and from $8.00 to $20.00 per kg between May and July, which is the period of the year most favourable for asparagus production in the sub-tropical and tropical areas of northern Australia.
Research conducted by Agriculture Western Australia at Kununurra in the Ord River Irrigation Area (ORIA) has not only demonstrated that asparagus can be produced in the tropics during May, June and July but that it has the potential to be a profitable commercial enterprise.
Growers in tropical and sub-tropical areas of Australia could aim to replace imports during May to June and aim to supply both the Australian and export markets during July to August when temperate areas in the northern hemisphere cease production.
Asparagus is a fairly labour intensive crop but is well suited to small holdings, up to eight hectares, with sandy or levee soils, and access to irrigation.
In temperate environments, it is normal practice to wait three years after planting the crowns to allow accumulation of carbohydrates in the storage roots (rhizomes) before starting to cut spears. During the autumn, the above-ground ferns die off but the crown and root system survive underground and resume growth in the spring.
In a tropical environment, such as the ORIA, the ferns remain green and the development and growth of new buds and storage roots is a continuous process. In the tropics, asparagus plants can be expected to produce their first harvest one year after seeding and remain productive for 9 to 12 consecutive years.
During the first year, the harvest period in a tropical environment can be expected to be about one week and the yield about 0.5 t/ha. Each year, the harvest period and the yield can be expected to double, up to year four, when the harvest period will be about two months and the yields 4-5 t/ha.
Following the harvest period, the practice is for the spears to be allowed to continue their natural development into ferns until the next season. It is important to apply fertilisers and adequate water during the summer months, in order to promote fern growth.
Asparagus can be established from seeds, seedlings or crowns but seed is the recommended method in the ORIA. The current recommended cultivar is UC 157 F1 sown to give a final population of 22 000 plants/ha with plants 30 cm apart in a single row on a 1.5 m bed.
The crop grows best in well aerated sandy and sandy loams but has performed well on the clay loams and clay soils of the ORIA. The depth of the crown affects the diameter of the spears and 150 to 200 mm is considered about optimum.
The level of fertiliser application will depend on the soil type and the cropping history of the land. However, as a guide the following application rates have been found adequate in trials at the ORIA: a basal application of 30 kg/ha P and 30 kg/ha K is applied prior to sowing and 20 kg/ha N is applied about a month later, when three or four ferns have opened.
Once established, fertiliser applications need to match crop growth and annual applications of 60 to 150 kg/ha N and 20 to 40 kg/ha K have been found to be satisfactory. Because growth is continuous, efforts have been made to apply the fertiliser in small split applications applied fortnightly during the harvest season and monthly thereafter, using a trickle irrigation system.
Few problems have been experienced with disease amongst asparagus crops in the ORIA. Crops have been free of the major diseases experienced in temperate areas. The cluster caterpillar, Spodoptera litura, and grasshoppers have been the major pests attacking the crop.
Weed control is difficult and costly in established crops, so effective control of weeds in the establishment phase is important. One of the current priority areas for research is to find a post-emergence herbicide that does not harm asparagus plants in a tropical environment.
Winter production of asparagus in Australia is currently limited to only about 25 ha but tropical areas, such as the ORIA, are seen as offering potential for expansion.
Any claims made by authors in the Australian New Crops Newsletter are presented by the Editors in good faith. Readers would be wise to critically examine the circumstances associated with any claims to determine the applicability of such claims to their specific set of circumstances. This material can be reproduced, with the provision that the source and the author (or editors, if applicable) are acknowledged and the use is for information or educational purposes. Contact with the original author is probably wise since the material may require updating or amendment if used in other publications. Material sourced from the Australian New Crops Newsletter cannot be used out of context or for commercial purposes not related to its original purpose in the newsletter
Contact: Dr Rob Fletcher, School of Land and Food, The University of Queensland Gatton College, 4345; Telephone: 07 5460 1311 or 07 5460 1301; Facsimile: 07 5460 1112; International facsimile: 61 7 5460 1112; Email:
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