Soils and Agriculture of the Palau Islands 1 
A. J. Vessel and Roy W. Simonson 2 
Soils of the Palau Islands range from 
deeply weathered Latosols 3 to shallow, rocky 
Lithosols, and include Regosols, Alluvial 
Soils, and Organic Soils. Most extensive in 
the islands are the Latosols, of general interest 
because of their wide distribution in the 
humid tropics. Associated soils are much less 
extensive but are more important to local 
food production. The latter also illustrate 
effects of local factors in soil formation. Data 
on characteristics, distribution, and utilization 
of the soils and a preliminary evaluation of 
their agricultural potentialities are given in 
this paper. More complete descriptions of the 
soils are part of a comprehensive report on 
the geology and soils of the islands now being 
prepared for publication as a professional 
paper of the U. S. Geological Survey. 
GEOGRAPHIC SETTING 
Location and Extent 
Most western group of the Caroline Islands, 
the Palau chain is almost directly south of 
Tokyo and due east of Mindanao. Location 
of the group in the western Pacific Ocean is 
1 A reconnaissance soil survey of the islands was 
made in 1948 as a part of a cooperative program of 
soil and geological mapping of islands in the western 
Pacific Ocean carried out cooperatively by the Corps of 
Engineers, U. S. Army, and U. S. Geological Survey, 
Department of the Interior. Manuscript received June 
12, 1957. 
2 Soil Scientists, Soil Survey, Soil Conservation 
Service, U. S. Department of Agriculture. The authors 
were on assignment to the U. S. Geological Survey and 
the Corps of Engineers for the mapping of the Palau 
Islands. 
3 Latosol is a term proposed within the past few 
years to include zonal soils formerly called Laterites, 
Reddish-Brown Lateritic soils, and Yellowish-Brown 
Lateritic soils (Kellogg, 1949). 
shown in Figure 1. Lying 7° north of the 
equator, the Palaus are in the same latitude as 
Colombia and Venezuela. 
The Palau chain stretches approximately 50 
miles, from Kay angel at the north to Angaur 
at the south. From east to west, the dimen- 
sions of the chain range from 3 to 25 miles, 
as measured to the outer barrier reefs. 
The total land area of the group, which 
consists of some 350 closely spaced islands 
and islets, is 175 square miles. Babelthuap, 
largest island in the group, has an area of al- 
most 140 square miles. The bulk of the re- 
maining land area is distributed among eight 
additional islands. Most of the 350 islands 
and islets of the chain are tiny reefs or bars, 
barely above sea level. 
Physiography and Topography 
The four types of islands in the Palau group 
are reef and atoll islands, platform islands, 
high limestone islands, and volcanic islands 
(Tayama, 1953). The reef and atoll islands, 
by far the most numerous, are flat land sur- 
faces only a few feet above sea level. Ex- 
amples of this type are Kayangel atoll at the 
north end of the chain and the many small 
unnamed reefs and atolls north of Peleliu. 
The platform islands, also mainly flat, are a 
little higher than the reefs and atolls. Angaur 
and Peleliu are chiefly of this type, though 
part of each consists of limestone ridges. The 
high limestone islands rise steeply out of the 
sea and are mostly narrow and elongated in 
shape. A few have the form of mushrooms. 
The principal high limestone islands are 
Urukthapel and Eil Malk; these and the nu- 
merous small ones all lie between Kotor and 
Peleliu, approximately 25 miles apart. Parts of 
281 
SMITHSON irvft 
it r\ \ i 
