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南太平洋海域調査研究報告
OCCASIONAL PAPERS

No.58（2017 年 3 月）
No.58（March 2017）

Production and Distribution of Potatoes
in the Kagoshima Island Areas
SAKAI Norio
Faculty of Agriculture, Kagoshima University

Abstract
Potato production is important in Japan, especially in island areas. Potato production and price haveincreased in the Kagoshima island area. The red soil on the islands allows the production of healthy looking
potatoes. Potatoes grown in island areas are produced during the mainland non-growing season and are soldas fresh potatoes.
Broadly, there are two types of potato collectors in the islands, Japan Agricultural Cooperatives andpurchase brokers, who compete with each other in terms of prices and services. Each collector plays a rolein the potato market.
Keywords: distribution, JA, Nagashima Island, Okinoerabujima Island, potato, purchase broker,
Tanegashima Island, Tokunoshima Island

Introduction
Potato varieties such as sweet potato, potato and taro are important crops in Japanese
agriculture and are grown in remote areas and island areas. Potato farmers face many
challenges in regards to potato cultivation and marketing. However, there are only a few
previous studies on potato production and distribution in island areas (IMURA et al. 2015,SAKAI 2016, SAKAI and NAITOH 2016).
In the current paper, I describe the current state of potato production and distribution in
the island area of Kagoshima Prefecture.

Potato Production and the Preferences of Consumers Pertaining to Potatoes in Japan
Main potato production areas in Japan
Potato production is the highest among vegetable crops in Japan and is important not

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SAKAI Norio

only for Japanese agriculture but also for Japanese consumers. The main prefectures that
produce potatoes are Hokkaido, Nagasaki and Kagoshima (Fig. 1, 2). These prefectures aregeographically distant from the main markets such as Tokyo and Osaka.
Hokkaido Prefecture
Hokkaido Prefecture accounted for 82.5% of potato production in Japan during 2014. In
Hokkaido, 44%, 24%, 14% and 18% of potatoes are grown for starch, food processing, foodapplications and seeds and other uses, respectively. Potatoes for use in food products are
harvested from summer to fall and are sold until April.
Nagasaki and Kagoshima prefectures
Nagasaki and Kagoshima prefectures produce potatoes for food applications and market
an image of fresh produce. Nagasaki Prefecture accounts for 4.4% of potato production inJapan, with potatoes shipped from May to June. Kagoshima Prefecture yields 4.1% of total
potato production, and potatoes are shipped from January to May. Both prefectures ship freshpotatoes during the period in which Hokkaido cannot ship fresh potatoes.
Preferences of consumers for potatoes in Japan
Japanese consumers value esthetically pleasing produce and show preference to potatoes
grown in red soil. Consequently, potatoes grown in red soil are the most expensive of all thepotato varieties.
In addition, different types of potatoes are used for different purposes. The round type of
potato is used for potato salad and croquettes due to its soft texture. The ellipse type potatoes
are used for boiled dishes and soup because this type does not disintegrate during cooking.

Ibaraki
1.7%
Kagoshima
4.1%

Chiba
1.2%

Others6.2%

Hokkaido

Nagasaki
4.4%

Nagasaki

TokyoOsakaKagoshima
Hokkaido
82.5%

Fig. 1. Potato production in Japan.

Fig. 2. Map of Japan.

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Production and Distribution of Potatoes in the Kagoshima Island Areas

Potato Production in the Kagoshima Island Areas
Potato producing area in Kagoshima Prefecture has been increasing since the 1980s(Fig. 3). In Kagoshima Prefecture, potatoes are mainly grown in island areas (Fig. 4, Table 1).
The potatoes produced on islands are generally shipped to the mainland.
ha
5,000
4,500
4,000
3,500
3,000
2,500
2,000
1,500
1,0000

1973
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
2000
01
02
03
04
05
06
07
08
09
10
11
12500

year

Fig. 3. Potato planted area in Kagoshima Prefecture.

Table 1. Potato producing regions in Kagoshima Prefecture.

Fig. 4. Map of potato producing regionsin Kagoshima Prefecture.

Planted area(ha)Yield(t)Harvestingseason

TokunoshimaIsland338

6,820

Feb.-Apr.

Okinoerabujima
Island

1,052

14,780Feb.-Apr.

TanegashimaIsland193

4,063

Feb.-Apr.

South Osumi

253

5,450

Mar.-Apr.

NagashimaIsland1,130

27,100Apr.-May.

Others

1,444

33,487―

Kagoshima
Prefecture

4,410

91,700―

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SAKAI Norio

During summer, it is difficult to grow vegetables in island areas because of strong
typhoons and drought. In addition, the remoteness of island potato production areas poses aneconomic disadvantage because it is expensive and time-consuming to transport products off
the islands. Therefore, farmers grow sugarcane and rear beef cattle in summer.
In winter and spring, it is too cold to grow vegetables and flowers on the mainland inJapan. However, because the island areas remain warm, farmers grow vegetables and flowers
for the mainland. Because the soil type on islands is mainly red derived from coral limestone,
farmers can produce fresh red soil potatoes during winter and spring. Therefore, the price ofpotatoes produced on the islands of Kagoshima Prefecture is more than the average price ofpotatoes in Japan (Table 2). Consequently, potato sales constitute approximately 70% of thevegetable crop sales in the Amami Islands.

Table 2. The price of potatoes in Tokyo Central Market.
Japan
Shipment
quantity (t)Produced in Kagoshima
Price(JPY/kg)

Shipment
quantity (t)Price(JPY/kg)

2008

37,95098

10,312

141

2009
2010
2011
2012
2013
2014
2015

41,66242,01444,27645,75048,88948,82949,797

119
140
168
169
112
109
124

8,629
9,941
12,58914,424
14,281
15,055
11,339

160
205
233
157
110
144
211

Potato Distribution in the Kagoshima Island Areas
Potato distribution in the island areas is complex. Broadly, there are two types of potato
collectors in the island areas: Japan Agricultural Cooperatives (JAs) and purchase brokers,
who compete intensively with each other to collect potatoes.
JAs
JAs are large agricultural cooperatives, and almost every farmer in Japan is a member ofa JA. JA branches are widely distributed throughout Japan. In the island areas, JAs collectalmost half of the potatoes produced. Because every island contains a JA automatic potato
sorting facility, the potatoes collected by JAs are shipped to the mainland after being sorted on

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Production and Distribution of Potatoes in the Kagoshima Island Areas

each island. JAs do not buy potatoes from farmers; they instead send the potatoes to market
and receive sales commission from farmers.
So as to avoid competition among the islands, JAs coordinate the varieties of potatoes
and shipping destinations. For example, on Tokunoshima Island, farmers mainly produce theround type of potatoes that are shipped to Nagoya, whereas Okinoerabujima Island produces
the non-round type of potatoes, which are shipped to the south of Osaka.
Because JAs collectively constitute a large organization, they are responsible for a stablesupply of potatoes to the wholesale markets. Therefore, JAs ships potatoes to markets as soon
as they are received. However, continuous rain can delay the shipping of potatoes to themainland. Because red soil is a hard clay type soil, farmers cannot harvest potatoes for a few
days after a rainfall event. The option of JAs constructing a potato storage facility on themainland is uneconomical because the facility would need to be huge and would only be usedduring monsoon.
Purchase brokers
There are approximately 5–20 brokers on each island. The brokers buy potatoes fromfarmers, which are then transported to the mainland. Brokers generally deal with relatively
small numbers of potatoes. Because brokers have no sorting facilities on the islands, they sortthe potatoes on the mainland. After sorting, brokers sell the potatoes to wholesalers orretailers.
Brokers engage in price competition while buying potatoes from farmers. If one broker
buys at a high price, others have to raise their prices. However, there is no competition
between JAs and brokers regarding price, whereas they do compete with each other to provide
services to the farmers. Because JAs do not buy potatoes, competition with brokers relates toservices such as potato collecting, supplying harvesting labor, speedy payment to farmers andtechnical advice.
As mentioned above, because the business scale of brokers is relatively small compared
to JAs and that they are a private business, they can react rapidly to situations and behave
opportunistically. If the market price is too low, some brokers refuse to buy potatoes fromfarmers, which consequently place farmers in a difficult situation. Other brokers adopt astrategy of buying potatoes at a low price and storing them in mainland facilities.
Subsequently, during periods of continuous rain when JAs cannot supply potatoes, the brokers
sell the stored potatoes to the markets at a high price. For wholesalers and retailers, brokers
are useful when there is a shortage of potatoes. However, the behavior of brokers cansometimes lead to price volatility.

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SAKAI Norio

Future Problems
In the island areas of Kagoshima Prefecture, potato production and price haveexperienced continual increases. However, some problems that require solutions exist within
potato production. First, there is a shortage of potato harvesting labor on the islands; therefore,securing laborers or the development of harvesting technology is an important issue for thecontinuation of potato production.
Second, potato consumption in Japan has been declining because of the decreasing andaging population and the greater participation of women in the workforce. The price ofpotatoes will decrease in future. To prevent price decline, efforts will be required todifferentiate the products and increase their added value.

Acknowledgement
This work was supported by JSPS KAKENHI Grant Number JP25450326.

References
IMURA, T., NAITOH, S., SUGIMURA, Y. and SAKAI, N. 2015. Shipment Action and the Choiceof Distributor of Potato Farmers in Okinoerabu Island. Agricultural Marketing Journal ofJapan, 24(1): 61–67 (in Japanese with English Summary).
SAKAI, N. 2016. Farming in South Kyushu and the Nansei Island: The Roles and Prospects ofSweet Potato for Starch and Sugarcane. Japanese Journal of Food, Agricultural andResource Economics, 67(1): 11–20 (in Japanese with English Summary).
SAKAI, N. and NAITOH, S. 2016. The Characteristics of Taro Production and Shipment
Behavior of Farmers in Subtropical Small Island. Agricultural Marketing Journal ofJapan, 24(4): 39–45 (in Japanese with English Summary).