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2. DISTRIBUTION OF TROPICAL PEAT


2.1 Extent
2.2 The Main Occurrences
2.3 Application of Research

2.1 Extent

The extent of peat in tropical and subtropical regions, particularly in developing countries, is only known approximately. Estimates of total global resources of peat conflict for several reasons:

i. Repetition of source error - Information is copied from the literature and accepted without checking or referring to the level of accuracy of the data supplied.

ii. Mapping scale errors - Information is taken from small scale soil maps, such as the FAO/UNESCO World Soil Map at 1:5 million scale. Such maps can only show areas with organic soils if they are extensive. Smaller areas are frequently shown in association with Hydromorphic soils or Gleysoils without indication of the percentages of the organic components in the associations. In some cases the existence of an organic component is not distinguished at all.

iii. Classification error - Mapping of organic soils depends on the local classification. Some countries only recognize organic soils if of significant depth or extent, others incorporate shallow mucky and peaty soils with hydromorphic soils.

iv. Nature of source - Organizations mainly dealing with land evaluation for agriculture and organizations whose objective is the assessment of peat deposits for energy purposes, have different interests to serve and their mapping approaches often differ and are incompatible.

As well as these basic sources of error figures are commonly misquoted because acres are confused with hectares (as in Ekono 1981, for the USA). Finally in some cases, where there is insufficient knowledge, rough estimates have been made by those supplying the information. Information from the developing world is frequently updated as is shown by the regular increase in reported extent of organic soils from such countries during recent decades. Table 1 summarizes known information on global resources of organic soils including those in tropical areas. Peats falling within the scope of this Bulletin are estimated in the last column. This data compiled by Bord na Mona (1984) has been checked against information from a variety of sources (Lucas 1982; Ekono 1981; Kivinen and Pakarinen in a report to the 6th Int. Peat Congress at Duluth 1980; Driessen 1977; Andriesse 1974) and in a few cases amended. The information, in particular that for tropical countries is likely to be revised as more reliable data becomes available. Present information indicates that throughout the world organic soils cover 436.2 million hectares of which 35.8 million hectares (8.2 percent) are in the tropics and subtropics.

The area may be much larger. Kivinen and Pakarinen (1980) suggest that total global resources cover 420 million hectares and they believe that it may approach 500 million hectares. The author is inclined to agree with this because the resources of organic soils in the Amazon basin and in the wet equatorial belt of Africa are under-estimated. Table 2 gives estimates of the extent of organic soils in tropical and subtropical regions.

The figures in Tables 1 and 2 for South East Asia are probably over-estimates. In the author’s opinion, based on substantial experience in the region, the figures for Indonesia in particular tend to be exaggerated because they are based on air-photo interpretation. Subsequent mapping has revealed that much of the land interpreted as swamp is occupied by mineral soils.

In Africa, Beadle (1960) indicates that in Uganda alone there are already 6 400 square kilometres of permanent swampland and as much land temporarily inundated in the wet seasons. Part of this land is likely to be peat, but how much can only be guessed.

The study of peat resources in the Amazon basin is only just beginning but early reports indicate vast areas of organic deposits (Suszcynski 1984). There are 270 reported occurrences along the Atlantic coast of Brazil. This leads the author to believe that the total area of peat deposits in the tropical and subtropical belt will in the end prove to cover at least 40 million hectares constituting about 11 percent of the world total.

Table 1 GLOBAL RESOURCES OF ORGANIC SOILS AND THEIR DISTRIBUTION (source Bord na Mona 1984)

Country

Area (ha)

Estimated % in Tropics

Western Europe

Austria

22 000


Belgium

18 000


Denmark

120 000


Finland

10 400 000


France

90 000


FRG

1 110 000


Great Britain

1 580 000


Greece

5 000


Iceland

1 000 000


Ireland

1 180 000


Italy

120 000


Luxembourg

200


Netherlands

280 000


Norway

3 000 000


Spain

6 000


Sweden

7 000 000


Switzerland

55 000



25 986 200



Eastern Europe

Bulgaria

1 000


Czechoslovakia

30 750


GDR

489 000


Hungary

30 000


Poland

1 300 000


Romania

7 000


Soviet Union

150 000 000


Yugoslavia

100 000



151 957 750



Africa

Angola

10 0001

100

Burundi

14 000

100

Congo

290 000

100

Guinea

525 000

100

Ivory Coast

32 000

100

Lesotho

-

-

Liberia

40 000

100

Madagascar

197 000

100

Malawi

91 000

100

Mozambique

10 0001


Rwanda

80 000

100

Senegal

1 500

100

Uganda

1 420 000

100

Zaire

1 000 0001

100

Zambia

1 106 000

100


4 856 500



Asia

Bangladesh

60 000


China

4 200 000

30

Fiji

4 000

100

Indonesia

17 000 000

100

India

32 000

100

Israel

5 000

100

Japan

250 000


Korea (DPR)

136 000


Malaysia

2 500 000

100

Papua New Guinea

500 0001

100

Philippines

6 000

100

Sri Lanka

2 500

100

Thailand

68 000

100

Vietnam

183 000

100


24 886 500



Central America

British Honduras

68 000

100

Costa Rica

37 000

100

Cuba

767 000

100

El Salvador

9 000

100

Honduras

453 000

100

Jamaica

21 000

100

Nicaragua

371 000

100

Panama

787 000

100

Puerto Rico

10 000

100

Trinidad and Tobago

1 000

100


2 524 000



South America

Argentina

45 000


Bolivia

900

100

Brazil

1 500 000

100

Chile

1 047 000

10

Colombia

339 000

100

Falkland/Malvinas Is.

1 151 000


French Guyana

162 000

100

Guyana

813 880

100

Surinam

113 000

100

Uruguay

3 000

100

Venezuela

1 000 000

100


6 173 000



North America

Canada

150 000 000


USA-Alaska

49 400 000


USA-S of 49° N

10 240 000

25


209 640 000



The Pacific

Australia (Queensland)

15 000

100

New Zealand

150 000

30


165 000


1 Author’s estimate
Table 2 RELATIVE IMPORTANCE AND REGIONAL DISTRIBUTION OF TROPICAL ORGANIC SOILS

Location

Estimated extent

Million hectares

Global %

Tropical %

All tropical and subtropical regions

35.80

8.21

100

S.E. Asia (including Papua)

20.26

4.65

56.6

Caribbean

5.67

1.30

15.8

Amazonia

1.50

0.34

4.19

African Continent (not subdivided)

4.86

1.11

13.58

South China

1.40

0.32

3.9

Other regions

2.11

0.49

5.9

2.2 The Main Occurrences

The South East Asian region comprising areas surrounding the South China Sea and areas in Papua-New Guinea contain the largest expanse of peat deposits, together forming 57 percent of all known tropical peat resources. The South China Sea is a large geosynclinal basin, around the littoral of which peat has accumulated in a similar way to former geological times, when eventually coal and lignite resources were formed. The second most important area is the Amazon basin and the basins bordering the Gulf of Mexico and the Caribbean (Venezuela, Guyanas, Florida).

In the wet equatorial belt of Africa a distinction can be made between the areas flanking the Gulf of Guinea, another large depressional area, and those in Central Africa where peat formation has followed recent geological uplift, rift formation and volcanism. Some of the peat areas in Central Africa are at high altitude where conditions are more like those found in temperate regions. The full extent of the areas bordering the Gulf of Guinea is not known but, because conditions are similar to those found in South East Asia, it is surmised that they are probably extensive in Gabon, Congo and Zaire.

2.3 Application of Research

Peats of tropical areas when compared with those found in temperate regions are insufficiently studied. Those in Florida which are of subtropical nature, have perhaps been studied most extensively, in particular their agronomic aspects (Phillips 1985). The results of these studies are of considerable importance to tropical peats at large.

Preliminary basic studies on properties of tropical peats and their agricultural potential in Indonesia are described by Polak (1941). Studies were discontinued during the Second World War and it was not until the nineteen fifties that agronomic studies restarted on tropical peats in South East Asia, mainly in Malaysia (Coulter 1957). Peat research stations were opened at Klang in Peninsular Malaysia, and at Stapok in Sarawak. Results of some 20 years of agronomic research carried out in these stations are now available to serve the region (Kanapathy and Keat 1970; Kanapathy 1976 and 1978; Kueh 1972; Tie and Kueh 1979).

Investigations into the more fundamental characteristics of tropical peat swamps, abandoned during the Second World War were taken up again in the early nineteen sixties, in Malaysia by Anderson (1964), and in Indonesia in the nineteen seventies (Subagyo and Driessen 1972; Driessen and Rochimah 1977). The latter studies were prematurely terminated and have not restarted. In most other tropical countries peat research is little developed, or non-existent. The behaviour of organic soils and peatswamps upon reclamation has received very little attention, even in Malaysia where research efforts were mainly concentrated on agronomic aspects.

The research conducted at Klang and Stapok and that mentioned earlier in the Florida Everglades has valuable applications for other tropical regions. Once it has been established through careful classification which peat and peatswamps are comparable, it will be possible to extrapolate and apply the information elsewhere. For this reason the peat materials and their environment must be adequately characterized, defined and classified first. Much of this Bulletin is devoted to such topics in Chapters 3 and 5.


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