128 
Journal of Agricultural Research 
Vol. VIII, No. 4 
These conclusions were accepted by Rolfs (6, p. 19). 1 Hart (4, p. 565) 
states: 
Closely connected with the subject of soil is that of fertilizers, by the understanding 
use of which almost any kind of orange may be, as it were, manufactured to order. 
Free use of potash thickens and toughens the rind, giving the firmness and durability 
requisite to bear transportation and rough‘handling, but at the expense of saccharine 
qualities. The latter may be increased and acidulous qualities modified by the use 
of more phosphoric acid. Highly nitrogenous applications give fruit surcharged with 
insipid juice, and cause a lush growth of wood that never properly ripens, inviting 
attacks of insects and fungi. Composts from the barnyard, or those containing much 
decomposing animal matter, must be used sparingly, if at all. The most wholesome 
growth and finest-flavored fruit comes from judicious employment of the best high- 
grade commercial fertilizers. 
The first conclusions based on experimental work in Florida are 
apparently those of Collison (2). In the valuable report presented he 
has tabulated a large number of analyses of oranges from trees receiv¬ 
ing high- and low-potash fertilizers and high- and low-phosphoric-acid 
fertilizers. He finds that a high-potash fertilizer does not make a 
sweeter fruit than the low-potash, “contrary to the very general opinion,” 
but that much potash does increase the amount of acid, an opinion pre¬ 
viously reported by Webber. Collison found further that phosphoric 
acid “probably had no material influence on the variation in the sugar 
and acid content of the fruit.” Unfortunately, he was unable to obtain 
satisfactory samples from which to draw conclusions in regard to the 
effect of nitrogen. 
The figures on which this paper was based have since been published 
in full (3). 
Colby (1) has made a large number of analyses of oranges grown com¬ 
mercially. In discussing the results obtained, Hilgard (5, p. 181), after 
discussing the unsatisfactory nature of the experiment (due to poor 
sampling, conflicting factors, and the short period of time), concluded.as 
follows: 
The oranges not fertilized (No. 2), those fertilized with potash and nitrogen (No. 8), 
and with nitrate of soda (No. 3) are all about alike, though No. 8 was a little sweeter 
than No. 2. The latter is a pleasant orange, though somewhat lacking in character 
(i. e., sprightliness and tartness). 
In character the oranges from the “Complete fertilizer 5 ’ (No. 10) are above those 
fertilized with nitrate of soda alone (No. 4), and while high in flavor, are not equal to 
those from the superphosphate group (No. 4). 
The highest citrus qualities are possessed by the oranges fertilized with superphos¬ 
phate alone (No. 4), and next by those from the “Complete fertilizer” (No. 10), and 
both rank high in flavor. 
In sweetness the .oranges fertilized with potash and nitrogen (No. 8) and with nitrate 
of soda are above those not fertilized. 
The oranges from the nitrogen and phosphoric acid lot (No. 6) are not as good as 
those from the superphosphate alone (No. 4), and have less character than those not 
fertilized (No. 2). Those from the potash and phosphoric acid lot (No. 9) are not of 
as good quality and are more variable than the above. 
1 Reference is made by number to “ Literature cited,” p. 138. 
