Climate and Possibility of Growing Fruit Treesin Papua New Guinea

著者 "TOMINAGA Shigeto, TAURA Satoru, HAYASHIMitsuru"

journal orpublication title

南太平洋海域調査研究報告=Occasional papers

volume 21page range 7-12URL http://hdl.handle.net/10232/16744

Kagoshima Univ. Res. Center S, Pal.,Occasional Papers, No. 21, 7 - 12, 1991

Survey Team I, Report 2. The Progress Report of the 1990 Survey of the Research Project,"Man and the Environment in Papua New Guinea''

CLiMATE AND POSSIBILITY OF GROWING FRUIT TREES

IN PAPUA NEW GUINEA

Shigeto ToMINAGA, Satoru TAURA and Mitsuru HAYASHI

Introduction

The authors investigated the changes of agricultural production and feature the tree

fruit production in Papua New Guinea (PNG). It is clear that agriculture is the main component

of the economy in PNG. However, the agricultural production systems are of smallholding,

except for some plantation crops such as coconut, cacao, coffee and oil palm. Although

production systems of these crops are on large scale which is called estate, culture of other

tree fruits is small and mainly for self consumption or for domestic market.

In this program entitled "Man and the environment in Papua New Guinea" of Kagoshima

University Research Center for the South Pacific, the authors collected some literature on

both the agricultural production and the climate conditions in PNG. The authors carried

out a survey around Port Moresby and Lae. The map of PNG is shown in Fig. 1. Agricultural

Fig.1 Maps of Papua New Guinea.

Provinces, provincial headquarters

and general geographical features.

Source: A time to plant and a time to uproot.

S, ToMINAGA el al.

data used was published by the Department of Agriculture and Livestock of Papua New

Guinea. The climatic data in PNG is shown in the･book entitled `Climate of Papua New

Guinea' written by ∫. R. McALPINE and Gael KEIG.

As a result of the survey, the authors had some comments on the future of the tree

fruit production.

Resuits and Discussion

1. Tree Fruit Production in PNG

Useful data of agricultural products for export was obtained from the reports entitled`Agricultural extension improvement study, Volume 1 Main report'published by the Department

of Agriculture and Livestock of Papua New Guinea, which was fun°ed by the Australian

Govern meれt.

Table 1 shows the acreage of large-　and Small-holding agricultural productions for

export in PNG. In 1990, the production area of coconut was predominant, followed by

cacao, coffee, oil palm and rubber. The estates, which are large farms, were found to

be in rubber, cacao and oil palm growing. On the other hand, small holdings were found

to be growing coffee. The reason was that coffee trees were grown mainly on slopes in

highlands because they prefer cooler climate. Other cash crops for export could be cultivated

under extensive culture condition and in large acreage.

Table 1 Production area and smallholder of crops for export in PNG.

Crop Total Area (ha)　Smallholder (%)　　Estate (%)

Coffee

Cocoa

Coconut

Oil palm

Rubber

Other minor crops

47,000

128,000

263,000

28,000

15,700

2,400

86

57

64

58

52

81

Source : Agricultural extension improvement study, Vol. I Main Report(1990).

Table 2　Net return of various crops for export in PNG.

Net Returns NPV*　at 12%

Crop Kina/man ･ day Kina/ha

Coffee (mature arabica)

Coffee (newly established arabica)

Cocoa (sole planted)

Cocoa (under coconut)

New Cardamon (Malabar with drier)

Mixed Vegetable Production

Chillie

Pyrethrum

I.33

0.75

4.39

2.20

7.43

2.28

3.17

Source : Agicultural extension improvement study, Vol. 1 Main Report(1990).

* : `NPV'- Net present value.

Climate and Possibility of Growing Fruit Trees in PNG

Table 3　Projected production volumes of major crops for export in PNG.

Estimated <一一一一一一一一一一一一一一一一一一一一一一一一一一一一一Projected一一一一一一一一一一一一一一一一一一一一一一一一一一一一一> Growth

p.a･

1987　　　　1988　　　　1989　　　　1990　　　　1995　　　1987-95

C offee

Cocoa

Copra

Coconut oil

Palm oil

Palm kernel

Rubber

Tea

64,740　　　46, 100　　　48,000

35,600　　　37,600　　　40,loo

94,800　　　95,000　　　95,000

42,100　　　41,000　　　41,000

130,000　　135,000　　161,000

18,700　　　20,300　　　24,100

5,300　　　　5,500　　　　5,700

6,500　　　　7,000　　　　7,000

49,900　　　60,700

43,100　　　58,100

95,000　　　95,000

41,000　　　41,000

187,000　　299,000

28,100　　　44,800

5,900　　　　6,900

7,000　　　7,000

-1%

Source : Agricultural extension improvement study, Vol. I Main Report(1990).

Table 2 shows the net return of various crops for export. Net return of smallholder

was best for new cardamon mixed vegetable production, followed by chillie, pyrethrum, cacao

and coffee.

Table 3 shows projected production volumes of major crops for export. The export

of oil palm was the largest, followed by copra and coffee until 1988. The forecast of production

after 1989 by the Government says that the production of only oil palm will increase and

the production of all the other crops will not.

2. C一imatic condition of PNG

The distribution of mean annual rainfall over PNG is shown in Fig. 2. Mean annual

亀.

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≡≡三塁蕊や 劔��=≡≡重職一一≡喜一萱一一上ヾ.'

｡,●o●▼ m●● 劔剩鎚��[9tｨ����=ﾉdﾂ纖�H���

国 劔富崎�|｢ﾘ����ﾆ��耳蒔Cfﾒ�c���.��C����#����

'tS

十一1 ､････.ei. -

Fig.2　Mean annual rainfall in PNG.

Source : Climate of Papua New Guinea(1983).

%

%

%

%

%

%

%

6

　

0

　

0

　

0

　

1

　

3

　

1

=

　

　

　

日

日

10 S. ToMINACA el al.

rainfall varies from under lOOOmm to over 7000mm dependent on the regions. This variation

of rainfall is considered to be caused by the height and the location of each region. The

highest annual rainfall was observed in the area around Purari river.

Fig. 3 shows the seasonal distribution of rainfall. In January, heavy rainfall was observed

mainly in the north and west areas of the country. While言n July heavy rainfall areas

were around the Purari river and the south and east areas of the island. Thus, the wetter

parts of PNG with high rainfall varied seasonally as affected by the direction of wind.

We consider that crop culture would be very hard at the areas with more than 3000mm

of rainfall a year. In drier regions, however, many fruit trees which originated in subtropical

and tropical regions could be grown.

Distribution of mean maximum and minimum temperatures in January and July are

shown in Fig. 4 and Fig. 5, respectively. These figures show only a small seasonal temperature

variation over the whole country, and the changes in mean maximum and minimum

temperatures are mainly dependent on height above sea level. For example, mean maximum

露曇憂国!園 ≡≡三三三三≡三三三三三≡≡三重重量重さ1タ -i---.≡三重≡≡≡重量三三三31● ニー=i一一二==二王ここ===一審ここここ饗場"A

繋誌こ､ヾ 冒.00-3,;mmm-＼､､-"＼＼

ロ<lOOmm＼ヽ

/ ■●一′ 一● -et○I 剖2ﾒ�

重量墓誌oe. ��r�ｻ��- ��

I○○ ��

:ぎー I ����2�

ら 国璽>400mm ��ｸ�H7襄��

巨星100-399mm ��ﾈ�ﾂ�

ロ<100mm

b-

Fig. 3　Seasonal rainfall patterns in PNG.

a-January, b-July

Source : Climate of Papua New Guinea(1983).

し,: I三三三 亦��ﾈ�ｲ�G.含 i C一二三〇

I

--_I.ー )Rl､M()博SIIYーeeL

ち

I ●●一一 ●●●.-i I､9--....,..e●he i:.:i::I-..､.筆 帽��覲����R粫U�靄���ﾆﾂ�

鰭. 鷲 ｢､.

臼30-'C32I酬liM(冊細 田28-30 m2年28 咾｣�モ��+��

ロ15-24

0　<15

b-

Fig.4　Mean maximum temperature in PNG.

a-January, b-July

Source : Climate of Papua New Guinea(1983).

令.全

置 ��葛 ● ��●● ��"�Lae で ､-_⑨㊦ゝ ヽプ

C-=-I-_ ヽ一一.〟- 茜雲 拳重 し一一一 〇一二-,: 〇一〃,一一.一一 Ja0 日 � ��ﾂ�

Moresby Ju一y oc Eil9-

o●

Ⅲ) 14-20　　Ⅲ0 13-19

ロ　6-14　　　ロ　5_13

0　く6　　　　0　く5

Fig. 5　Mean minimum temperature in PNG.

Source : Climate of Papua New Guinea(1983).

Q

E璽;ン`●

.3.-a-.-上

一6ヽ一〇

2.lSAMIeJStJ

｡喜.`●〟'- ~一一〇 i

e ii 亦�336 -a 30▲oe●○〟3′▲ 930

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･&.

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om'田圃suJL'ooL-,.a"叫､e

巨訓藍d棚M,酉-d　田圃…d　｡..…ON,.〟.

田.?,･,,,藍C,酉年-･3　回-id　田柄'i:"00m

間

Fig.6　Climate classification for PNG based on altitude and mean annual rainfall.

Source : Climate of Papua New Guinea(1983).

temperatures in the lowland range around 28-32℃, and mean minimum of 20-24℃　at night

with coastal locations having slightly lower mean maximum and higher mean minimum than

interior lowland. While, in the highland, mean maximum temperature ranges around 15-

24℃　during day time and minimum of 5-14℃　at night.

These large variability in maximum and minimum, as affected by the height above

sea level, suggestes that many fruit species could be grown in PNG,

Fig. 6 shows the climate classification for PNG based on altitude and mean annual rainfall,

The climatic condition of PNG is divided into ll categories from dry subhumid to perhumid

in each: lowland, premontane, lower montane and upper montane. As described above,

many fruit trees prefer the subhumid to humid conditions in premontane and lower montane.

12 S. ToMINAGA et al.

From the above, we consider that many fruit trees, which orlginated in tropical 20me

and therefore do not have chilling requirement for breaking dormancy and/or flower initiation,

Could grow better in the areas of interior lowland and lower montane. On the other hand,

Some subtropical fruit trees such as oranges could grow in the areas of highland and

premontane.

3. Tree Fruits ObseNed in PNG

As a result of a survey in some locations, we observed several agricultural systems.

Besides, We could find many fruit tree species, although almost all of them were planted

alone or as a grove of a few trees. Largeholding cultivations, which are called estate

and are managed extensively with little hand labor, were found with coconut, oil palm,

cacao and rubber. More intensive agriculture systems were found in cultures of coffee

plant･ In coffee culture, We could see improvements in culture systems such as propagation

by grafting, cutback of primary scaffold branch -and establishment of drainage canal.

Forthermore, we observed very small scale culture of some fruit trees in home gardens.

These were banana, papaya, mango, pineapple and coconut for self consumption. In particular,

many banana varieties were present. There were many other subtropical and tropical fruit

trees found in some areas in PNG. We saw passion fruit, papaya, cashew, mango, sugar

apple, soursop, common custard apple, coffee, cacao, oil palm, Tahiti chestnut, Java almond,

avocado and jack fruit etc., although they were all grown as a few trees.

Comments

Because the climate in PNG is warm and wet, the authors suggest the following : warm

and wet climate will be suited to the cultivation of many kinds of tropical and subtropical

fruit trees･ But the climate will also permit the attack of many disease and insects to

the trees. The excess moisture on high water table soils will cause erosion and leaching

of nutrients. Thus, construction of drainage canals and soil fertilization to soil were

recommended for successfull fruit tree production. Also, Control of diseases and insects

are needed to grow fruit trees introduced to PNG from foreign countries.

Reference

DENOON,D and SNOWDEN,C.. A time to plant and a time to uproot. 17-32. Institute of

Papua New Guinea Studies, Papua New Guinea.

DENSLEY, D.R.∫..　Agriculture in the economy, Marketed fruit and vegetables. 2-56.

Department of Primary Industry, Papua New Guinea.

Department of Agriculture and Livestock of Papua New Guinea 1990. Agricultural extension

improvement study, Vol. I Main report. 2,2-2,13. Department of Agriculture and Livestock

of Papua New Guinea, Papua New Guinea.

HAYASHI, M., NEDACHI, M., NAmNO, K. and MIYAWAKI, K. 1990. Kagoshima Univ. Res. Center

S.Pac., Occas. Paps,, 20: 8-12.

KISHIMOTO, 0･, HAYASHI, M., MATSUZAWA, Y. and HIGASHI, T. 1985. Japan ∫. Trop. Agr. 29(1) :

1-8.

McALPINE, ∫. R, and KEIG, G. 1983. Climate of Papua New Guinea. 61-101. Australian National

University Press, Canberra.