Burdock

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Project experiments for 1998 / 1999

• GPPIS (FAO)
• Purdue University, Indiana
• botany.com

Species: Arctium lappa

Family: Compositae

Crop status: New

Fresh burdock is boiled, stir fried and used in soups and stews. A popular Japanese dish is kimpera, which is sliced burdock fried in a sweet soy and sesame sauce. It has become common in mixed vegetable (in liquid) bags, and is also used as a pickle, paste, as a tea (Vinning 1995) and as a soft drink (Larkcom 1991). It is valued for its high fibre, high vitamin B, low calories and tastelessness (hence, used for texture in cooking). Medicinal properties include relief of arthritic pain, high inulin content, diuretic, and it is rumoured to be an aphrodisiac (Vinning 1995).

Varieties

Japanese classify burdock in to several groups, including Takinogawa, Oura, Hagi and Echizen Shiroguki. Takinogawa is the most common, with slender long roots and red petioles. The others have thicker and shorter roots (Nguyen 1998). See Seedquest for a list of seed providers.

Agronomic trials

Agriculture WA is currently conducting an HRDC project looking at variety x location trials and postharvest quality aspects (SC Tan 1998, pers. comm.). Jeff Hastings (SE Queensland) and Agriculture Victoria are also conducting variety x season trials in 1999. Adaptation trials are being conducted at Rockhampton (David Midmore 1999, pers. comm.). NSW Department of Agriculture have previously conducted trails aimed at developing exports to Japan, and processing second grade produce (Murison 1996). Observation trials have been conducted at Myrtleford, Victoria, and at Murwillumbah, NSW. A number of trials have failed because inappropriate soils caused deformed or unharvestable roots (Peter Simmul 1998, Tas; SC Tan 1998, WA). Sandy soils have not yet been trialled in Tas, though the plant is likely to grow well (Peter Simmul 1998, pers. comm.).

Production

Burdock has been grown in NSW, Vic (Lee 1995), Tas and WA. Large scale production is inhibited by the lack of appropriate machinery (Vinning 1995).

Climate: Burdock is a temperate crop that prefers warm, humid climates. It tolerates a wide range of temperatures but prefers 20 - 30ºC. Frosts will kill leaves but not roots, and the plant will shoot again in the following spring (Nguyen 1998).

Season: It can be sown in spring or autumn. Autumn sown plants become dormant over winter, but must be small during the cold period (roots <5 mm) or they will bolt early in spring (Nguyen 1998). Bolting is initiated by low temperature followed by day lengths greater than 12.5 hours (Larkcom 1991). Probably a short season, winter crop in Darwin (Kevin Blackburn 1998, pers. comm.). Plant Sept - Nov at Narranderah, too hot for seeds to germinate in Dec, and harvest late April (Mark Robertson 1998, pers. comm.). Plant in Oct - Nov and harvest Mar-Apr to supply the Japanese market up to June (SC Tan 1998, pers. comm.). Autumn plantings appear to be favoured in Japan (Larkcom 1991).

Soil type: An unchanging soil profile for at least 60 cm is essential. Sandy or sandy loam soils with good drainage (Nguyen 1998). and no compaction (Burgmans 1996) are preferred. Although roots have a better appearance when grown in sandy or sandy loam soils, they tend to lack flavour (Nguyen 1992). Assess soil for burrowing nematodes, as they are a major pest (Nguyen 1998).

pH: Preferred range is 6.5-7.5 but it does not perform well in acid soils (Nguyen 1992).

Rotation: A crop that repels nematodes (oats, rape) can be sown during winter and incorporated into the soil before sowing burdock (Nguyen 1998).

Soil preparation: Soil must be deeply cultivated, up to 90 cm deep to reduce forking. A deep ripper is unlikely to be adequate, and preparation with a trench digger will produce higher quality roots by mixing the soil and fertiliser more evenly. Any change in soil or level of nitrogen fertiliser throughout the soil profile will lead to forking. A low N, high P (120 kg/ha in sandy soils) fertiliser can be worked into the soil during deep cultivation to encourage root growth. Pre-irrigate and spray emerging weeds just before or after sowing (Nguyen 1998). Ridges may be used to increase soil depth and drainage (Larkcom 1991). The Japanese use a specialised PTO driven implement for soil preparation and sowing (see Hamada et al. 1983). Agriculture Western Australia have a small version (2 of the normally 4 furrows) imported from Japan in 1998.

Sowing: Burdock can be planted when soil temperature rises above 10ºC, but establishment will be improved if temperature is above 15ºC (Nguyen 1998). Optimum temperature for germination is 20-25ºC (Larkcom 1991). Summer heat will also prevent seeds from germinating (Mark Robertson 1998, pers. comm.). Direct seed about 1-2 cm deep and keep wet until seedlings are established (Nguyen 1998). Crucial to sow into the rip ruts, to keep a high proportion of straight and unbroken produce (Mark Robertson 1998, pers. comm.). Germination is very slow and uneven, with 10-14 days from sowing to emergence. Seeds have sometimes been dormant until the following season. Germination rate can be greatly improved by using primed seed (Nguyen 1998). Soak in water overnight or scarify (Larkcom 1991). Also better in the light (PFAF 1998).

Plant spacing: 10 cm between plants and 50 cm between rows (Nguyen 1998) or 20 cm between plants and 25 cm between rows (Burgmans 1996). High density encourages long, straight roots (Larkcom 1991) and higher densities than these have been recommended (eg; PFAF 1998).

Fertiliser: Approximately 60 kg/ha elemental N and K at the two to three leaf stage, and 100 kg/ha elemental N and K three months after sowing (Nguyen 1998).

Irrigation: Once plants are established, reduce water to force roots to grow deeper (Nguyen 1998).

Weed control: Burdock establishes slowly, giving weeds a head start. Further weeds after sowing can be cultivated or hand chipped out. Full canopy cover is achieved after about 8 weeks, restricting further weed development (Nguyen 1998).

Harvest: Time to harvest is 4-5 months if planted in spring, 7-8 months if planted in autumn. Harvest when roots are 20-35 mm diameter and over 70 cm long. Delaying harvest for too long will cause a decrease in quality (woody, pithy roots). Slash and mulch tops, leaving 10 cm of stalk. Loosen roots with a vibrating ripper and then pull out by hand (Nguyen 1998, NSW Agriculture have one; see Hamada et al. (1984) for a description). Roots are considered to have a better flavour if harvested before flowering. Burdock used for medicinal use is harvested after a year (Burgmans 1996).

Yield: Japanese yields have steadily increased, reaching 19.1 t/ha in 1996 (Figure 3). New Zealand trials have produced yields of up to 39 t/ha (Burgmans 1996).

Postharvest

Handling: Harvest in the morning and keep in the shade until transferred to the packing shed. Wash and remove side shoots and root hairs, then pack into plastic lined 10 kg boxes (Nguyen 1998). Keep cool and moist until stored (Nguyen 1992). The white flesh rapidly dries and oxidises after cutting, so it must be kept entire until just before use. It is usually wrapped in plastic when put in the fridge. The root should be cleaned by scrubbing, rather than peeling (Vinning 1995).

Temperature: Store at 0°C (Nguyen 1992).

Humidity: Store at 90-95% relative humidity. It is susceptible to wilting (Nguyen 1992).

Processing

The Chinese dry burdock by first cutting into 60 x 5 mm strips and then soaking in water, changing the water twice and then drying (Larkcom 1991). There is interest in New Zealand in processing burdock for Japanese niche markets (Burgmans 1996).

Quality assessment

Markets demand a 60 cm long, straight root that is free of soil (Vinning 1995). Japanese regard freshness and good shape as the most important quality requirements (Pan 1995). The Japanese grading system is given in Figure 1. The proportion of harvested burdock in each grade varies throughout the season.

Pests and diseases

There were few observed pests or diseases and no registered chemicals (Nguyen 1998). Plants are very resilient after the 3 leaf stage (Mark Robertson 1998, pers. comm.). See Hawaiian pests & diseases.

Nematodes and aphids are the most serious, with green looper caterpillars and leaf-eating ladybirds less common.

Blackroot (Aphanomyces raphani) is favoured by warm weather, causing dark irregular patches that will eventually cover the entire root. It is controlled by improved irrigation, soil drainage and crop rotation (Nguyen 1992).

Powdery mildew may be a problem in wet, humid conditions, but in most cases the crop will tolerate it without causing losses. Symptoms are similar to powdery mildew on cucurbits, though the agent is different (Nguyen 1998).

Potential viruses are listed at Plant viruses online (Brunt et al. 1996).

Export market

(click here for exchange rates).

The main markets are Japan, Korea, Hong Kong and Taiwan, particularly where there is an expatriate Japanese population (Vinning 1995). Rated a priority Asian vegetable for developing a fresh export market by workshop members reported in Lee (1996). Australia can produce burdock that is suitable for processing, but burdock suitable for the fresh market will take much more development.

Japanese demand has increased with an interest in dietary fibre (JETRO 1994), and with the rapid increase of Japanese style salad mixes that contain burdock (JETRO 1996), but production has waned to 248 000 t in 1996 (Figure 3) due to the highly labour intensive harvesting (JETRO 1994). Consumption is approximately 2.5 kg/person/year (Otsubo 1996). It comprises 4.7% of the Japanese fresh cut vegetable products (Pan 1995). Prices seem to be increasing, though have come down after almost doubling in 1991-92 (Vinning 1995). Prices appear to peak from April to July, toward the end of the Japanese off-season. No statistics are available for Japanese imports, but China provides most shipments (JETRO 1994). Total imports are thought to be about 10 000 t/year for fresh and frozen product (Vinning 1995) and are increasing (JETRO 1996). China is considered a low cost and low quality exporter (Vinning 1995) with inconsistency in volume and quality (SC Tan 1998, pers. comm.). China tarnished its reputation by supplying burdock contaminated with sulphur. AQIS require a declaration that the crop is free of burrowing nematode (Radopholus similis), which is present near banana producing country (Nguyen 1998).

Burdock is generally less successful as has been hoped, but it still appears to have significant market potential (Lee 1998). Higher prices might be obtained from organically grown (Nguyen 1998) or high quality produce (Vinning 1995). Western Australia Department of Agriculture has received strong interest from a Japanese importer, and they conducted a market study for burdock in Japan (SC Tan 1998, pers. comm.).

Burdock is available year round in Korea, where it is eaten boiled or as deep fried chips. Market value is increasing, reaching 4 billion Won in 1992 (Vinning 1995). The Korean market appears to have significant market potential for Australian exporters (Lee 1998).

The Taiwanese market experienced a surge in price in 1992, followed by a surge in supply in 1993, causing prices to fall back to the previous level of NT$30/kg. Prices are highest in January (Vinning 1995).

Related projects

SC Tan (Duration?). Developing new export vegetables with emphasis on burdock, daikon and globe artichoke. HRDC Project Number VG97042.

References

Anonymous (1996). Annual report of fresh fruit and vegetables. Tokyo Fresh Fruit and Vegetable Information Centre (In Japanese).

Brunt, A.A., Crabtree, K., Dallwitz, M.J., Gibbs, A.J., Watson, L. and Zurcher, E.J. (eds.) (1996 onwards). `Plant Viruses Online: Descriptions and Lists from the VIDE Database. Version: 16th January 1997.'

Burgmans, J. (1996). Crop Facts: Burdock - an Asian/European herb. The New Zealand Institute for Crop and Food Research Ltd., Christchurch. (URL: http://www.crop.cri.nz/home/index.jsp).

Hamada, Y., Aoki, H., Yamaguchi, Y. and Miyashita, H.. (1983). Studies on the mechanization of edible burdock (Arctium lappa L.) culture. I. Mechanical sowing of edible burdock. [Japanese]. Research Bulletin of the Aichi-Ken Agricultural Research Center No(15): 178-186.

Hamada, Y., Aoki, H., Miyashita, H., Yamaguchi, Y. and Tanabe, H. (1984). Studies on the mechanization of the culture of edible burdock (Arctium lappa L.). II. Measurement of pulling resistance for harvesting and a field trial of a test digger. [Japanese]. Research Bulletin of the Aichi-Ken Agricultural Research Center No(16): 138-146.

JETRO (1994). Frozen Vegetable. Japan External Trade Organisation, Market Report

JETRO (1996). Frozen Vegetables: Access to Japan's Import Market-1996. Japan External Trade Organisation, Market Report

Larkcom, J. (1991). Oriental vegetables: the complete guide for garden and kitchen. London, John Murray 232 pp.

Lee, B. (1995). Audit of the Australian Asian vegetables industry. RIRDC Research Paper No. 95/13. Canberra, Rural Industries Research and Development Corporation 97 pp.

Lee , B. (1996). Assessment of economic benefits for Asian vegetables. RIRDC project CON-4A review meeting 14 November 1996.

Lee, B. (1998). Assessment of economic benefits for selected Asian vegetables. Access to Asian Foods (3): 2. (URL: http://www.nre.vic.gov.au/trade/asiaveg/nlaf-03a.htm).

MAFF (1999). Abstract of statistics on agriculture, forestry and fisheries. Statistics and Information Department, The Ministry of Agriculture, Forestry and Fisheries of Japan.

Murison, J. (1996). Asian vegetable research in New South Wales. The Australian New Crops Newsletter 5. (URL: http://www.uq.edu.au/~gagkrego/newslett/ncnl5-8.htm).

Nguyen, V. Q. (1992). Growing Asian vegetables. Agfact, NSW Agriculture H8.1.37.

Nguyen, V. Q. (1998). Burdock. The New Rural Industries. Ed.: K. W. Hyde. Canberra, Rural Industries Research and Development Corporation: 155-162.

Otsubo, M. (1996). Asian vegetables into Japan: export potential, opportunities and myths. In: Proceedings of an Asian Food Industry Conference (Ed; Lee, B. and Prinsley, R.). RIRDC Research Paper No. 96/9: 22-28.

Pan, C. (1995). Market opportunities for fresh and processed Asian vegetables. RIRDC Research Paper No. 95/14. Canberra, Rural Industries Research and Development Corporation 117 pp.

Vinning, G. (1995). Market Compendium of Asian Vegetables. RIRDC Research Paper No. 95/12. Canberra, Rural Industries Research and Development Corporation 386 pp.