Rural Industries Research & Development Corporation

Welcome to the EDAMAME (VEGETABLE GREEN SOYBEAN) chapter of RIRDC's major new publication (contents page here) on nearly 100 new rural industries.

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Introduction

The cultural practices for green soybean are identical with ordinary soybean except that the green pods are harvested at the mature green stage when the pods are almost filled.

It is evident from recent studies that green soybean can be grown in New South Wales and Victoria for the January to April markets. November and December are the ideal times to grow green soybean for the highest pod yield which is comparable to the average yield of 8 t/ha in Japan. Green pods from November and December plantings could also be marketed in January, February and March, which would coincide with the most favourable period for export to Japan. However, since Japanese quarantine restrictions prohibit entry of fresh green soybean from mainland Australia, green soybean targeted for Japan must be in the processed form. Only fresh-market green soybean produced in Tasmania, is allowed to be exported to Japan.

Markets and marketing issues

1. Imported fresh-market green soybean: Imported fresh-market green soybean mainly came from Taiwan. China, Thailand and the Philippines also supplied freshmarket green soybean to Japan but occupied a very low proportion (only 10%) of the whole import market. In 1993, Japan imported 5,617 t of fresh-market green soybean. Of this, 850 t was sent to the Tokyo markets. Monthly imported volumes and landed prices are shown in Table 2 (not available in this html version).

The landed prices varied monthly but the peak occurred in March and was ¥648/kg. However, average prices for the five-year period 1990-1994 showed that January, February and March are the best times for green soybean with February being the time for highest prices in the Tokyo market (Table 3- not available in this version).

2. Imported frozen green soybean: In 1993, Japan imported 51,250 t of frozen green soybean of which 75% or 38,229 t came from Taiwan and 22% or 11,088 t came from China. The remaining 3% came from Thailand (1,805 t), USA (107 t) and South Korea (21 t). Average landed prices from these sources were:

Taiwan ¥210/kg

China ¥174/kg

Thailand ¥185/kg

USA ¥196/kg

South Korea ¥190/kg

Most of these imports were sold to the food service section at an average landed price of ¥201/kg. (Table 5 - not available in this html version). In Japanese supermarkets, frozen green soybean imported from China is sold at ¥228/400 g (or ¥570/kg.) while the Taiwanese product generally commanded a higher price of ¥300/400 g (or ¥750/kg).

The price difference is due to poorer quality product from China. Recently, the Chinese product has improved in quality as Taiwanese companies have transferred their processing technology to China, resulting in a larger volume of frozen green soybean being shipped to Japan in 1995 (Table 5 - not available in this html version).

3. Imported seed of vegetable green soybean: There is a small market for import of seed of green soybean into Japan. Hokkaido, the major seed production area for the Japanese green soybean market, has decreased in area from 476 ha in 1987 to 422 ha in 1992, resulting in short supply of approximately 200 t of seed. In Australia, seed of green soybean would be produced in the southern coastal areas of New South Wales and on the east coast of Victoria. Pod shattering when ripening is the major problem for production in hot, dry inland areas.

Production requirements

Varieties

The planting time is from November to early January for the January to April markets. Sowing from mid-January is not recommended due to the risk of unfilled pods caused by cool weather in April. The tested cultivars which were used in this study were unsuitable in the Murrumbidgee Irrigation Area of New South Wales. Seed samples are available at the Gosford Horticultural Research and Advisory Station (Phone: (043) 481900; Fax: (043) 481910).

Agronomy

Fertilisation of green soybean in early growth of plants should be focused to form good plant height and to produce maximum pod numbers. The combination of N:P:K at the rate of 78 kg. N:104 kg. P:64 kg. K per ha should be applied as a basal dressing. However, to maximise the marketable pod yield, one side dressing of potassium nitrate at the rate of 100 kg. per ha (13N:46K) would be necessary at flowering. Lack of nutrition at reproduction stage could lead to an increase in number of unfilled and/or one-seed pods.

Irrigation—Green soybean requires a large amount of water for growing, particularly at the vegetative stage, for flower bud formation and for pod development. Insufficient water during flowering to pod growth stage reduces flower numbers and causes pods to drop.

Pest and disease control

Diseases and insects—The most common diseases and insects that were found on the Central Coast of New South Wales were Sclerotium crown rot (fungus Sclerotium rolfsii) and caterpillars of budworms (Helicoverpa armigera) and cutworms (Agrotis spp.). Warm and moist weather favours these diseases and insects.

Harvesting, packaging and postharvest handling

Pod yield of cultivars growing on the New South Wales Central Coast achieved a high yield of 9 t/ha in the December plantings.

Mechanical harvesting—The fresh bean harvester does a very good job in harvesting green soybean, removing approximately 76% of beans and separating foliage and stalks. Harvest time, using the single row machine, is approximately a quarter hectare per hour. Approximately 7% of beans harvested by machine were bruised.

There are three types of vegetable green soybeans sold in Asian markets which are:

Attached type: (pod-bearing plant), marketed in bundle form which is the most desirable in fresh markets as Japanese customers believe this type keeps pod quality longer, ie. flavour and taste. The top leaves and small damaged pods are removed while whole plants with leaves, pods, stems and roots are packed in bundles or in 5 kg. wooden boxes or cartons.

Detached type: (pod only) is marketed in plastic net bags. Only marketable pods (two- and three-seed pods) are selected and packed in these bags.

Attached types usually obtain higher prices than the detached types because of better pod quality and these high prices meet the costs of transport.

Harvesting, de-podding and packaging are labour intensive and need to be carried out in as short a time as possible to retain the freshness of green pods.

Fresh bean: (bean only) in which beans are shelled and marketed as fresh beans.

The first two types are the most popular form in Japan while the fresh, shelled beans are most popular in the Chinese markets such as Taiwan, Hong Kong and Singapore.

Frozen green soybean, which is the major type of green soybean imported by the Japanese markets, is the detached type which is frozen by using Individual Quick Frozen (IQF) technology.

Specific processing requirements

• Blanching at 95°C constant for two minutes could easily produce `popped' frozen green soybean.

• After blanching and cooling, it is desirable that the temperature of the bean should be less than 16°C.

• Freezing immediately after blanching is recommended to avoid build up of bean tem-perature which would cause a high percentage of undesirably dark and bruised pods.

The Taiwanese processing flow chart is shown in Figure 1 (not available in this html version).

Future outlook

A previous study has shown that many tested cultivars which are high in yield and pod quality can be promoted by the Tasmanian vegetable industry, thus providing opportunities to target peak periods for demand of fresh markets in Japan during January, February and March.

For frozen green soybean, investigation of Japanese markets has shown that average wholesale prices have reduced annually since 1990 from ¥323/kg. to ¥163/kg. in 1995 (Table 4 - not available in this html version). The price reductions may be due to an increase of Chinese and SE Asian supplies. If the quality of Chinese supply improves, as mentioned above, wholesale prices could drop as low as ¥150/kg because of low labour costs in China and SE Asia. The value of Japanese Yen, which has recently decreased to ¥88/our Australian dollar (June, 1997) is an important factor for consideration. The break-even price for Australian frozen green soybean is A$1.55/kg. (Table 6 - not available in this html version).

Organic green soybeans in both fresh and frozen forms are also required by Japanese trade houses.

Key contacts

*About the author

Born in Vietnam, he studied in Japan and received his PhD from the University of Tokyo, Japan in 1977. He is currently involved in research into the development of Asian vegetables for domestic consumption and export to Asian markets.