20 BULLETIN 31, PORTO RICO EXPERIMENT STATION 
included in the fertilizer scheme. In the complete fertilizer the 
nitrogen was carried in ammonium sulphate. In the incomplete, 
ammonium sulphate was applied to three plats and sodium nitrate 
to three. Nine plats were given no fertilizer, and some of them 
varied in cultural treatment. 
The nine plats making the best growth by October, 1913, included 
six of the seven receiving ammonium sulphate and only one of the 
three treated with sodium nitrate. The ammonium sulphate plat 
not included received lime in addition to complete fertilizer. The 
nine plats making the poorest growth included two receiving lime, 
one basic slag, and one acid phosphate and potash in combination, but 
no others with mineral fertilizers. The plat receiving lime at the 
heavier rate, 2 pounds per tree each application, was adjacent to that 
treated with complete fertilizer alone at double the basal rate, or 1 
pound per tree. At this time the former averaged 12.9 inches high 
per tree, and the latter 20.7 inches. The measurements of October, 
1913, indicated that nitrogen in the form of ammonium sulphate 
was beneficial, whereas no apparent benefit was had from liming. 
The five plats of tallest trees, as measured in October, 1914, had 
received ammonium sulphate. The plats receiving complete ferti- 
lizer ranked first, fourth, eighth, and ninth, respectively. None of 
the ten poorest plats received any mineral fertilizer other than lime 
or basic slag. The poorest plat was that receiving the heavier appli- 
cations of lime. Trees on this plat averaged only 21 inches high, 
whereas those on the adjacent plat, which received complete fer- 
tilizer, averaged 45.5 inches high. 
Adjacent to the plat receiving ammonium sulphate alone and to 
the two plats receiving ammonium sulphate in combination with 
potash and with acid phosphate, respectively, were three other plats 
which received equivalent quantities of nitrogen in the form of 
sodium nitrate. The average height per tree of plats treated with 
ammonium sulphate was 48.4, 44.6, and 52.9 inches, respectively, per 
plat, whereas that of the correspondingly treated sodium nitrate 
plats was 29.4, 32.3, and 34.6 inches, respectively, per plat. Some of 
the trees produced a few cherries in 1913, but not enough to indicate 
fertilizer effects. The production showed an increase in 1914, but 
was still very small. Of 20 fruiting plats, the 5 leading ones received 
ammonium sulphate. The yields of the 10 best plats ranged in 1915 
from 2,133 to 9,351 cherries, and the yields of the 10 poorest plats 
ranged from nothing to 164 cherries. 
The plats of highest yield, named in the order of their merit, 
received complete fertilizer, ammonium sulphate and potash, com- 
plete fertilizer in double quantity, complete fertilizer and lime, guano 
m double quantity, complete fertilizer and manure, nothing, manure 
in double quantity, ammonium sulphate and acid phosphate, and 
ammonium sulphate alone. These 10 plats included all of the 7 
receiving ammonium sulphate, but none of the 3 receiving sodium 
nitrate. 
The 10 plats of poorest yield, 2 giving nothing, included those 
receiving lime alone, sodium nitrate alone, and sodium nitrate in 
combination with acid phosphate, but no other fertilized plat. 
The yields of the three plats receiving ammonium sulphate for com- 
parison with sodium nitrate were 7,655, 2,133, and 2,140 cherries, 
