302 
Journal of Agricultural Research 
Vol. XIV, No. 8 
Table HI.—Chemical composition of soil used 
Plant nutrient. 
Percentage 
composi¬ 
tion of 
oven-dried 
soil. 
Quantity 
per acre 
of 2.000,000 
pounds of 
soil. 
Nitrogen. 
0.032 
.026 
.094 
.041 
•154 
.082 
Pounds. 
640 
520 
1,880 
820 
3,080 
1,640 
Phosphoric acid. 
Potash... 
Lime. 
Magnesia. 
Table IV .—Petrographic analysis of soil 
Percentage of 
minerals not 
quartz in— 
Abundant 
minerals not 
quartz in— 
Less abundant minerals not quartz in— 
Remarks. 
Sand. 
Silt. 
Sand. 
Silt. 
Sand. 
Silt. 
2-4 
None.. 
None,. 
Orthoclase (residues), 
microcline, epidote, 
tourmaline, magne¬ 
tite, hornblende. 
Epidote, tourmaline, 
zircon, rutile, mag¬ 
netite, sillimanite, 
hornblende, musco¬ 
vite, biotite, garnet. 
Soil characterized by 
low content of min¬ 
erals other than 
quartz. Only trace of 
mica present. Min¬ 
erals existing are of a 
refractory nature. 
CONDITIONS OF PLANT GROWTH 
The equivalent of 40 pounds of oven-dried soil was carefully weighed 
out, the various plant nutrients were added in the amounts given in 
Table V and were mixed thoroughly by rolling over and over on canvas 
cloth. This was transferred to 4-gallon glazed earthenware pots. 
Sufficient drainage was obtained through small openings on the lower 
side of each pot. 
Nitrogen and phosphoric acid were added to all pots two weeks before 
seeding each crop. Potash and lime were added only at the beginning 
of the experiment. 
The rates of application were made on the basis of 200 and 400 pounds 
of potash per acre. For convenience of expressing the data obtained, 
in Tables V to X the treatments are referred to as the mineral which 
carries potash in weights of 200 pounds per acre. The figure “ 2 * before 
the name of the potash carrier indicates that this plant nutrient has 
been applied at the rate of 400 pounds per acre. 
This work was conducted out of doors in a cage of X-^h-mesh poultry 
wire. Excessive heat is prevented in summer by a lattice-work cover 
similar to those used in covering ginseng beds. During spring and 
summer the pots were placed on benches 2 feet above the surface of the 
ground. In winter they were buried in a mixture of sawdust and soil 
sufficiently deep to prevent freezing. 
