FERTILIZERS FOR COFFEE IN PORTO RICO 25 
averaged 200 grams per tree, and 9 of the 12 trees exceeded this 
weight. The weight of leaves from nonnitrogen treated trees aver- 
aged 81 grams, and only 1 of 15 exceeded 100 grams. 
On November 30, 1915, the trees were cut at the surface of the 
ground and the trunk and branches were weighed. The weight of 
the trees receiving nitupgen averaged 259 grams, whereas that of 
trees receiving no nitrogen averaged 150 grams. 
The roots were carefully washed and air-dried for several day- 
prior to weighing. Because of the heavy soil, it was impossible not 
to lose some fine roots. The weight for all trees receiving nitrogen 
averaged 93 grams, whereas for the others it averaged 65 grams. 
In this test it was very evident that nitrogen exerted a marked 
influence in stimulating the development of the young trees as was 
shown in their greatly increased number of leaves, amount of woody 
growth above ground, and root growth. 
COMPARISON OF AMMONIUM SULPHATE, SODIUM NITRATE, LIME, AND SULPHUR 
In the West Field plat tests the favorable effect of ammonium sul- 
phate was very marked, but this was not true of sodium nitrate or of 
lime. The sulphur was therefore further studied in pot tests. 
The bottom of 5-gallon cans was lined with coarse pebbles to 
permit of drainage, and the containers were filled with red clay 
soil which was removed to a spade's depth from a hillside and thor- 
oughly mixed. In a test it was found that 0.992 gram of hydra ted 
lime was required to neutralize 1 kilogram of soil. The seedlings, 
from the seed of a single tree, planted May 26, 1915, were each set 
in cans on September 13, 1915. The treatment was given in tripli- 
cate. Group 1 received ammonium sulphate (8 grams per can per 
application) ; Groups 2 to 6, inclusive, sodium nitrate (4. 8, 10, 12, 
and 16 grams, respectively) ; Groups 7 to 12, inclusive, hydrated lime 
(at the rates of 1,000, 2,000, 4,000, 8,000, 16,000, and 32,000 pounds, 
respectively, per acre) ; and Group 13 was left untreated (check). 
The lime was applied 5 days prior to transplanting the seedlings, 
and was twice worked through the upper layer of soil. Over 4 
inches of rain fell before the trees were set. On account of the 
injurious effect of liming it was necessary, within the first month, 
to replace 3 dead trees of Group 12, and to replace a second time 
two of the same group, and two badly wilted trees of Group 11. 
At a little less than 4 months, tree 1 of Group 10 was in so poor a 
condition that it also was replaced. 
The nitrogen was given in three applications six months apart, be- 
ginning two weeks after the seedlings were set. Quarterly measure- 
ments of height were made, starting two months after setting, and 
notes were taken for two years. Figure 15 graphically gives the 
measurements. At the second and third measuring the two groups 
receiving the lightest applications of lime led. The fertilizer 
showed its effect on the plants in leaf color before any effect appeared 
in height, the dark green of the fertilized trees contrasting strongly 
with the yellowish hue of the limed and check trees, the contrast being 
less pronounced in Group 2. Early in the second year the nitrogen- 
fertilized trees began to grow more rapidly than the lime-treated 
group. At the sixth measuring each group of fertilized trees sur- 
passed the check in height with one exception, which equaled it, 
