19, 4 Reinking and Groff: Siamese Seedless Pummelo 407 
of the bed, down the middle of which at least one row of citrus 
trees is eventually planted (Plate 2, fig. 3). 
Some idea of the layout of one of these Nakorn Chaisrji pum- 
melo orchards can best be had from a study of Plate 16, which 
represents an actual locality at Ban Mai along Tachin River. 
All stages of the various cultural methods are shown. In the 
lower left-hand corner is an area of virgin nipa palm and grass 
swamp in which canals have been dug from Tachin River for 
irrigation and drainage. After the canals have been dug, this 
land is prepared with ditches, as shown in the plot in the lower 
right-hand corner. The land here is set off in beds and ditches 
and has been planted to bananas, sugar cane, corn, beans, and 
peanuts. These or similar crops are grown for about five years, 
at the end of which time the beds have settled and the entire 
piece of ground is ready for the pummelo plantation. The per- 
manent pummelo plantation, with its raised beds, trees, ditches, 
and irrigation canals, is clearly shown in the upper left-hand 
corner of the sketch. All these orchards and plantings are 
drained and irrigated by ditches within each plot that lead to 
canals running to Tachin River, 
When first laid out, the interior beds are usually 5 to 5.5 
meters wide. After all natural growth has been cleared and 
burned and tree stumps have been removed, shallow ditches are 
dug (Plate 3, fig. 1). All this work is done by hand, the sticky 
soil being cut in blocks by means of a special instrument devised 
for the purpose. These blocks are then tossed upon the surface 
of the beds (Plate 3, fig. 2). The plots will not be ready for 
the planting of the citrus trees for from three to five years, as 
sufficient shade has not been provided and the soil is not in good 
tilth. At first the trenches are made very narrow and shallow; 
and the beds are often first planted to sugar cane or, sometimes, 
to peanuts, as the soil becomes quite mellow after it has been 
properly drained (Plate 3, fig. 3). Bananas are sometimes 
planted as the first crop (Plate 4, fig. 1), as these provide ideal 
shade for the young pummelo or other citrus trees which may 
be planted later. 
IRRIGATION 
It will be seen at a glance that this system of canals, dikes, 
raised beds, and ditches provides not only for the drainage of 
the area, but also for its irrigation; as the water gates (Plate 4, 
fig. 2), constructed under the dikes at regular intervals, carry 
the high-tide waters of the dry season from the canals to the 
