Mechanization of Vegetable Soybean Production in Taiwan

Mechanization of Vegetable Soybean Production in
Taiwan
S. Shanmugasundaram, Plant Breeder and Director, Program I, Asian Vegetable Research and
Development Center, P.O. Box 42, Shanhua, Tainan 741, Taiwan, ROC. Email:
sundar@netra.avrdc.org.tw
Miao-Rong Yan, Research Assistant, Legume Unit/ Program I, Asian Vegetable Research and
Development Center, P.O. Box 42, Shanhua, Tainan 741, Taiwan, ROC. Email:
yanmr@netra.avrdc.org.tw
Introduction
Vegetable soybean is a labor-intensive crop. From seeding to harvesting, vegetable soybean
requires 700 person-hours/ha (Hsieh and Su, 1991). As a result, nearly 50% of the production
cost goes to labor. Therefore, as early as 1984, it was proposed that to remain competitive in
international trade, the cost of production of vegetable soybean in Taiwan must be reduced by
mechanizing planting and harvesting operations and optimizing other management inputs (Liu
and Shanmugasundaram, 1984).
In this paper, the history of mechanization of soybean production, from seeding to
harvesting, stripping pods and shelling pods were reviewed and described.
Seeding
Traditionally, vegetable soybeans were planted after the harvest of the rice crop. Without
tillage, vegetable soybeans were planted manually by making a small hole with a trowel near the
rice-stubble when the soil was still moist. Then the field was mulched with rice straw, which was
pressed close to the ground. Planting and mulching alone accounted for 25% of the total cost of
production (Liu and Shanmugasundaram, 1984).
The development of a zone-tillage pneumatic precision seeding machine in 1994 (Hsieh and
Su, 1991) marked the beginning of the highly mechanized systems used today in Taiwan. This
original machine was imported from Japan. It could make the furrow and plant 2 rows at 30 cm
apart on either side of the furrow and cover the seed with soil taken from the furrow in a single
operation. It could be pulled by a 28.5 HP tractor. More seed was required for planting and seeds
were not covered well; therefore germination rate were erratic.
In response, the second machine, a smaller version with 8-10 HP tractor was developed. A
rotavator first made the furrow (Fig. 1a). Then a planter plants 3 rows on the bed between the 2
furrows and covers the seed (Fig. 1b). The wheels of the planter conveniently move in the
furrow. Spacing between rows is 40 cm. The seeds are covered well and therefore, the
germination rates are high.

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Fig. 1a. Ditch maker.
Fig.1b. Three-row sowing machine.
In Chia-Nan area, vegetable soybeans are grown in upland with tillage. Tractor mounted
seeder makes 1-m wide bed and plants 2 rows per bed by vacuum sowing at 40 cm apart. In-row
plant spacing is about 5 cm. With a plant population density of 400,000 plants per ha for a 30
g/100 seeds variety, the seed rate is about 120-150 kg/ha. Depending upon the seed size and
germination percent, the seed rate should be adjusted.
Inter-cultivation
In the past, inter-cultivations such as fertilizing, weeding and spraying chemicals were all
done manually. Currently, tractor-mounted equipments are used for the above operations.
Harvesting
In the 1980s, the middlemen usually gathered the labor from the village around midnight
and took them to the field. The whole plant was harvested manually and the harvested plants
were transported to the village. Then the labor manually strips the pods under shade. The dew
and cool weather during harvesting and the shade during stripping helped to maintain the quality
of the pod.
In 1985, a mower-type bundle harvester was developed to harvest 2 to 4 rows at about 0.9
m/sec (Hsieh and Su, 1991).
A bundle thresher similar to a grain soybean thresher was also developed (Fig. 2). Instead of
a metal spike tooth or rasp bar, a hard rubber tooth is fixed with a keyhole in the center. The
optimum angular velocity for the threshing cylinder is 400 rpm and the damage rate is less than
10% (Hsieh and Su, 1991). The thresher can reach 95% efficiency to reach a capacity of 60
kg/hr. It is 6 to 8 times faster than hand threshing.
Fig. 2. Bundle thresher for vegetable soybean.

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Shanmugasundaram and Yan
At AVRDC, a very simple mechanical device to strip the pods was developed. A triangular
wooden board mounted on a bench is used to pull the plants through a small “\/” shaped slot
(Figs. 3a and b). It strips the pods and leaves (AVRDC 1990). Pods can be easily separated from
leaves by using a fan. A laborer can strip 250 plants/hr compared to traditional hand picking of
30 to 40 plants/hr (AVRDC 1989, 1990).
Fig. 3a. A simple wooden device
mounted on a bench to strip
pods from a stem.
.
Fig. 3b. Simple wooden-board device used to strip the pods.
The labor wage and appreciation of the NT dollar has steadily increased the daily wages
from US$5/day in 1981 to US$20/day in 1992 and to even higher levels today (Benziger and
Shanmugasundaram, 1995). About 120 person-hours are required to harvest one hectare. For
stripping the pods, an additional 360 person-hours are required. The total cost for harvesting and
stripping @US$20/day is US$1,200/ha. In addition, due to industrialization, the labor availability
has also become a problem. Therefore, Taiwan has decided to give priority to mechanization of
harvesting and stripping.
A number of bean harvesters were tested for their suitability to harvest vegetable soybean.
FMC 1647 was introduced from France and demonstrated to the farmers by Provincial
Department of Agriculture and Forestry (PDAF), District Agricultural Improvement Station
(DAIS) and AVRDC in 1994. FMC 1647 with 95 HP tractor could harvest 0.29 ha/hr when the
farm size was 10 ha or more. If the farm size was 0.5 ha or less, the efficiency was 0.22 ha/hr.
The engine speed is 1800 rpm and it runs at a speed of 2.1 km/hr. The loss due to various factors
ranged from 18.4% to 23.8%, which was rather high. To reduce harvest losses, FMC worked
with the farmers’ association and frozen food companies to improve their machine, heading to
the development of FMC 7100. With 190 HP, FMC 7100 operates at 3400 rpm (Fig. 4). The
actual loss was kept around 5% and the damaged pods were around 7% (Table 1). The total cost
of production could be reduced by about 20%.

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Shanmugasundaram and Yan
Fig. 4. FMC 7100 vegetable soybean combine harvester.
Table 1. Percent loss due to various factors in harvesting with FMC 1647 and FMC 7100
harvesters.
Item/Model
FMC 1647
FMC 7100
Pods left on the plant
3
2
Pod dropped in the field
4
2
Pods with soil, leaves, etc.
4
1
Mechanical damage to pods
11
7
At present, Taiwan has two FMC 1647 and 23 FMC 7100 harvesters. They are currently
owned by either the middlemen, the farmers’ association, and/or the frozen food factories.
Sorting and Shelling Machines
In the past, pods were sorted manually. Today, a mechanical sieve with a vibrating
frequency of 400 rpm is used to separate the pods (Fig. 5) with two or more seeds with sizes
acceptable to the market (> 1.4cm width and > 4.5cm long). It has an efficiency of 94.3% (Hsieh
and Su, 1991).
In the past, shelling was done manually. It was time consuming and also not good for
fingernails. Therefore, AVRDC developed a simple pod splitting tool (AVRDC 1990). A nail
placed on one end of the wooden stick is used to split the pods (Fig. 6).
A mechanical device has been developed to shell the beans (Fig. 7). It has a shaker with 1/4
HP engine to move the pods towards a rubber coated metal roller and a corrugated roller that
squeezes the pods to shell the beans. A 1/2 HP motor rotates the rollers. The machine can shell
500 kg pods/hr. A water hose with holes is connected to the length of the rubber rollers and water
runs over the rollers so that the green pods do not stick to the rollers and get crushed by the
rollers.

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Fig. 6. Simple tool to split the pods.
Fig. 5. Mechanical sieve to sort graded pods.
Fig. 7. Mechanical shelling machine for
vegetable soybeans.
Conclusion
Vegetable soybean is a labor-intensive crop. Between 1980 and 1990, when the labor cost
was low and labor was available, most production operations were conducted manually. With
increasing labor cost, decreasing labor availability and appreciation of the NT dollar, Taiwan has
gradually mechanized planting, intercultural operations, harvesting, threshing, sorting and
shelling of vegetable soybeans. Mechanization has reduced the cost of production by about 40%
and the vegetable soybean production remains competitive with other countries. Due to the
experience of farmers, the quality of vegetable soybean produced in Taiwan is better than those
from other countries and it helps to sustain the industry.
References
AVRDC. 1989. Progress report summaries 1988. Shanhua, Tainan, Taiwan. p. 25.
AVRDC 1990. 1988. Progress report. AVRDC, Shanhua, Tainan, Taiwan. p. 102.
Benziger, Vincent and S. Shanmugasundaram. 1995. Taiwan’s frozen vegetable soybean industry.
Techno. Bull. 22. AVRDC, Tainan, Taiwan. 15 p.

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Shanmugasundaram and Yan
Hsieh, Chin-Cheng and Chung-Sheng Su. 1991. Management inputs and mechanical harvesting
of vegetable soybean in Taiwan. In: S. Shanmugasundaram (Ed). Vegetable Soybean – Research
Needs for Production and Quality Improvement. AVRDC, Tainan, Taiwan. p. 61-64.
Liu, C.P. and S. Shanmugasundaram. 1984. Frozen vegetable soybean industry in Taiwan. In:
Ali, M.M. and E.S. Lion (Eds.). Vegetables and Ornamental in the Tropics. Proc. of the
Symposium on Vegetables and Ornamentals in the Tropics. UPM, Selangor, Malaysia. p. 199-
212.
Shanmugasundaram, S., Shi-Tzao Cheng, Ming-Te Huang and Miao-Rong Yan. 1991. Varietal
improvement of vegetable soybean in Taiwan. In: S. Shanmugasundaram (Ed). Vegetable
Soybean – Research Needs for Production and Quality Improvement. AVRDC, Tainan, Taiwan.
p. 30-42.
Acknowledgement
The authors gratefully acknowledge the generous financial support provided by the Council
of Agriculture (COA), Taiwan and continued encouragement by Dr. Shui-Ho Cheng of COA,
Taiwan.

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