8 02 
Journal of Agricultural Research 
Vol. XXIV, No. 9 
A 4-inch hole was cut in the center of each lid to accommodate the 
tree. About midway between this center hole and the lid margin, four 
equally spaced holes were cut, through which solutions could 
be poured. These holes were corked when not in use. The inside 
surface of the can was given a heavy coat of asphalt paint. 
The sand used in the cans upon mechanical analysis showed the 
following percentage composition: 
Size by screen (meshes per inch): 
Larger than 20 mesh. 
20 to 40. 
40 to 60. 
60 to 80. 
80 to 100. 
Smaller than 100. 
Per cent. 
o. 33 
7 . 8S 
54 - II 
21. 63 
16. 08 
Chemical analysis of the sand showed 99 per cent silica, 0.2 per cent 
volatile matter, and 0.8 per cent total water-soluble solids (other than 
silica or volatile matter), much of which was iron. 
A I-inch pipe, inserted through the lid and extending to the base of 
the can, provided a means for removing drainage water. About it and 
to a depth of 4 to 6 inches was placed a well-compacted layer of pure 
quartz rock crushed to about one-fourth to one-half inch in diameter, 
to prevent the sand from blocking the drainage system. The sand was 
added gradually and thoroughly moistened and settled before further 
additions, care being taken to avoid the use of excessive amounts of 
water. When the can was filled with sand to within about 2 inches 
from the top, the excess of water used in filling the can was at once 
removed through the outlet pipe. 
The drainage water was removed by means of powerful air-suction (7) 
(Gardner-Rix vacuum pump run by one-half horsepower motor, with a 
capacity of 9 cubic feet per minute), six to eight cans being usually drained 
in one operation. 
A slender iron tube (PI. i, B) was inserted through the drainage pipe 
to the bottom of the can whenever it was necessary to remove drainage 
water. As a means of excluding sand the lower end of the drainage 
tube was covered with a piece of fine tin screen. Excellent results over 
a period of years are readily obtained if the drainage water is removed 
as rapidly as it enters the drainage pipe. Plate i, B, shows one of the 
drainage bottles removed from its wooden rack and raised so as to show 
the general scheme used in removing the drainage water. 
The air outlet from each drainage bottle is provided with a gas cock 
by means of which the rate of flow into each bottle can be regulated. 
A 2-year-old Valencia orange tree was planted in each can after the 
soil was thoroughly removed from the roots by repeated washing. The 
root system was pruned until only a small part remained. The upper 
portion of the tree was also pruned (PI. i, A); the lateral shoots and the 
leaves were removed and the cut surfaces covered with asphalt paint. 
Where it was not desired to exclude calcium from the culture, the trees 
were given a coat of whitewash. Where whitewash was not applied, a 
cylinder of wire netting was placed about the tree and the east and south 
sides were protected with cheesecloth attached to the wire. When the 
trunk was shaded by new shoots, the cloth protector was removed, 
preferably during cloudy or foggy weather. After the tree was planted 
in the sand and the lid was placed on the can a piece of white oilcloth, 
with a hole in the center, was slipped down over the tree trunk and was 
fastened to the lid with asphalt paint. A thin wad of cotton was placed 
