You. VIII Washington, D. C., January 22, 1917 No. 4 
EFFECT OF FERTILIZERS ON THE COMPOSITION AND 
QUALITY OF ORANGES 1 
By H. D. Young, 
Assistant in Agricultural Chemistry , Agricultural Experiment Station of the University 
of California 
INTRODUCTION 
Of the great amount of work which has been done with fertilizers, only 
a relatively small proportion deals with their effects on the quality of the 
crop. This is especially true of fruits, partly because of the length of 
time required and partly because of the conflicting factors which enter 
into a long-time experiment. 
The material presented in this paper has to do with oranges (Citrus 
aurantium). The quality of this crop may offer an easier subject for 
study than most fruits, as the factors affecting it, such as the percentages 
of sugar and acid, the texture of the fruit as a whole (its specific gravity), 
and the proportions of juice and rind, can be accurately measured. 
HISTORICAL REVIEW 
There have been a number of theories and expressions of opinions put 
forth as to the effect of the usual fertilizers on the composition of oranges. 
Webber (7), basing his conclusions largely on the experience of intelli¬ 
gent orange growers in Florida, wrote: 
(1) By a proper combination of the various elements used in fertilization one can 
undoubtedly largely govern the quality and flavor of the fruit. 
(2) To obtain a fruit with thin rind, use nitrogen from inorganic sources in moderate 
quantities, with considerable potash and lime. 
(3) To sweeten the fruit, use sulphate of ammonia in considerable abundance, de¬ 
creasing the amount of potash. 
(4) To render the fruit more acid, increase the amount of potash and use nitrogen 
from organic sources. 
(5) If it is desired to increase the size of the fruit, as is sometimes the case, apply a 
comparatively heavy dressing of nitrogen in some organic form and slightly decrease 
the other elements. In the case of the tangerine and mandarin, where a larger size is 
usually desired, a heavy dressing of nitrogen fertilizers would favor this end, and is 
not objectionable unless carried to excess. 
1 Paper No. 32, Citrus Experiment Station, College of Agriculture, University of California, Riverside, 
Cal. 
(127) 
Journal of Agricultural Research, 
Washington, D. C. 
gw 
Vol. VIII, No. 4 
Jan. 22, 1917 
Key No. Cal.—8 
