i9, 4 Reinking and Groff: Siamese Seedless Pummelo 405 
10. The topsoil, which was collected under a tree in the orchard, 
proved to contain 1.006 per cent of salt; the clay subsoil con- 
tained 0.8 per cent of salt; and the canal mud, 2.5 per cent 
of salt. The canal mud was collected from the bottom of a 
canal, the water of which contained 2.11 per cent of salt, as shown 
in Table 10. The soil in orchards at Bang Bakok contained 
only a small amount of salt at the time of the year the samples 
were taken. The topsoil contained only 0.18 per cent of salt 
and the canal mud only 0.33. During June the water used for 
irrigation at Bang Bakok, as shown by analysis, contained 
only an amount of salt normal for river water; consequently 
the orchard soil and the canal mud would not be expected to 
contain a high percentage of salt. These comparative tests 
would seem to indicate that the difference in the salt content 
of soils in Ban Mai and soils in Bang Bakok has some bearing on 
the difference in the quality of the fruit produced in each region. 
As before stated, it has been the general belief that salt has a 
direct relation to the quality of the fruit produced. Tests on 
the salting of trees would seem to confirm this belief. The 
chemical tests of the water and the soil, at least for the month 
of June, give an accurate indication as to the presence of an 
excessive amount of salt in the soil that produces the best-quality 
pummelos, and would indicate that the salt content has some 
relation to the quality of the fruit produced. 
CULTURAL METHODS 
The type of citrus culture used in Nakorn Chaisri is exceed- 
ingly well adapted to the low, wet, mud flats and nipa swamps 
of the region. From the description of the general physical 
aspect of the country it is evident that unique treatment is 
required before any measure of success can be attained. The 
methods followed are very largely those employed by the Chinese 
in the successful planting of fruit in the flood-swept delta regions 
of southern China. This type of fruit culture, almost unknown 
in the West, deserves careful consideration as of possible use 
in the development of many of the otherwise useless swamp 
areas of other parts of the world. 
Nakorn Chaisri is irrigated, drained, and sometimes flooded 
by the waters of Tachin River. Untouched by the hand of 
man, this swamp area is covered with nipa palm, Nipa fruticans 
Wurmb (Plate 1, fig. 1), or other plants adapted especially to 
wet and salty conditions. Much of the foreshore of Tachin 
River is still covered with this wild growth, giving the impres- 
181287 2 
