I3 6 
Journal of Agricultural Research 
Vol. VIII, No. 4 
The average sugar content for the two crops of each variety is 9.19 
for the upper tier and 9.16 for the lower, showing very .close agreement. 
In every case, except that of the Valencia crop for 1915, the individual 
plots of the lower tier (P, Q, R, S, T) show the same characteristics as 
those of the nitrogen plots in general—that is, 'the fruit from them had a 
lower sugar content, a little more acid, a slightly lower specific gravity and 
percentage of juice, and a higher nitrogen content than that from other 
plots not fertilized. While the data indicate a somewhat richer soil in 
the lower tier of plots, the differences are not sufficiently great to affect 
materially any conclusions that may be drawn from the experiment as a 
whole. 
COMPARISON OF ORANGES FERTILIZED WITH COMMERCIAL FER¬ 
TILIZER AND ORGANIC MATTER 
The plots in the fertilizer experiment have been kept in clean cultiva¬ 
tion throughout the experiment. In adjacent plots on the same type of 
soil are trees of the same age which have received large amounts of stable 
manure, together with rock phosphate and a leguminous cover crop. 
The trees on these plots present a thriftier appearance and bear more 
fruit than the trees in the fertilizer experiment. There is a general im¬ 
pression that the use of a cover crop and organic matter tends to produce 
oranges of coarser texture and poorer quality. Analyses of fruit from 
the cover-cropped plots were made along with those from the fertilizer 
plots. The results obtained do not indicate any great difference, and 
although some variations appear, the closeness of the agreement is rather 
striking, as is shown by Table IX. 
Table; IX .—Composition of oranges fertilized with commercial fertilizer and with 
organic matter 
Crop. 
Fertilized plots. 
Cover-crop plot. 
Spe¬ 
cific 
grav¬ 
ity. 
Juice. 
Sugar, 
Acid. 
Nitro¬ 
gen 
Spe¬ 
cific 
grav¬ 
ity. 
Juice. 
Sugar. 
Add. 
Nitro¬ 
gen. 
Navel : 
Per ct. 
Per ct. 
Per ct. 
Per ct. 
Per ct. 
Per ct. 
Per ct. 
Per ct. 
1914 . 
0. go 
45 - 7 
9 - 13 
I. IO 
O. 087 
O. 89 
45-8 
9 * 15 
I* 05 
0.104 
, * 9*5 .. 
.88 
41.4 
10. 12 
.98 
. 108 
.86 
37-8 
9.96 
•95 
. 129 
Valencia: 
* 9*4 . 
.91 
1 
&31 
•97 
. Ill 
• 9 1 
47-3 
8. S i 
.92 
.128 
* 9*5 . 
•93 
5 2 * 9 
8. 69 
• 70 
. 119 
.91 
30. 0 
8-44 
• 79 
•135 
Two explanations suggest themselves as accounting for the greater 
quantity of nitrogen found in the fruit from plots to which nitrogen has 
been applied. (1) In the presence of a greater quantity of available 
nitrogen in the soil the orange tree is able to absorb this element in 
excess of its needs. (2) The greater quantity of nitrogen was necessary 
for the promotion of more normal growth. It seemed rather improbable 
