FERTILIZERS FOR COFFEE IN PORTO RICO 
23 
trogen. The growth of the different groups is shown graphically in 
Figure 14. 
In April, 1915, five noninterested persons who were asked to name, 
in their opinion, the groups showing the darkest leaf coloring un- 
Fig. 14. — Average height of young coffee trees grown in cans. Nitrogen has increased 
growth 
hesitatingly pronounced the four nitrogen-treated groups of darkest 
green color. Counts of the leaves per tree were made June 19, 
1915. Table 10 shows the number of leaves per tree. 
Table 10. — Number of leaves on young coffee trees grown in cans ivith different 
fertilizer treatments 
Number of leaves 
Varia- 
tion from 
check 
Percent- 
Fertilizer'applied 
Tree 
No. 1 
Tree 
No. 2 
Tree 
No. 3 
Total 
age of 
check 
N 
157 
85 
98 
176 
76 
82 
165 
102 
85 
135 
117 
104 
152 
160- 
114 
170 
112 
80 
150 
110 
105 
157 
165 
108 
150 
93 
90 
442 
312 
307 
485 
401 
304 
485 
307 
255 
+135 
+5 

+178 
+94 
-3 
+178 
0) 
-52 
144 
P 
102 
K 
100 
NP _..: 
158 
NK 
131 
PK 
99 
NPK_. 
158 
O 
100 
0' 
83 
i Check. 
All groups receiving nitrogen showed a heavy increase in foliage. 
The lengths of 50 similarly placed leaves on each tree were meas- 
ured to one-eighth inch. Variation between the check and any 
other group was less than 7 per cent, and no correlation could be 
seen between the kind of fertilizer applied and leaf length. At 
