May 14,1917 
Soil Nitrogen and Nutrition of Citrus Plants 
209 
instances little or no increase is found. The light application of nitrog¬ 
enous fertilizer has apparently increased the nitrate content of the soil 
very little over the unfertilized plots. This, of course, does not neces¬ 
sarily mean that the application of the nitrogenous fertilizers to these 
plots has not resulted in an increased nitrate supply, but rather that the 
nitrate has been assimilated almost as rapidly as formed. The character 
of the trees on these plots shows that the light application of nitrogenous 
fertilizer has resulted in the development of a larger and more thrifty tree 
than those produced by the control plots. The trees on the lightly 
fertilized plots have also produced more and better fruit. 
Table XIII :—Seasonal variation in nitrates in furrow-irrigated soils receiving no nitrog¬ 
enous fertilizers. September, 1914, to August , 1915, inclusive 
[Results expressed as milligrams of nitrogen per 100 gm. of soil] 
Period. 
Plot B. 
Plot D. 
Plot I. 
Depth.inches.. 
1914. 
September. 
October. 
November. 
December. 
1915* 
January. 
February.. 
March. 
April. 
May. 
June. 
July. 
August. 
1914. 
September. 
October. 
November. 
December. 
1915- 
January... 
February. 
March. 
April. 
May. 
June. 
July. 
August. 
0-6 
6-18 
18-30 
30-42 
Cr~6 
6 -l8 
18-3O 
0-6 
6-18 
18-30 
30-42 
o. 94 
.92 
.76 
.88 
o. 46 
.18 
•15 
•25 
• 25 
• 15 
• 15 
.08 
•34 
•13 
. xr 
.04 
o. 46 
•32 
. II 
.18 
. II 
•25 
.08 
. II 
.04 
. 08 
. II 
.08 
1.00 
I. 20 
•95 
.88 
0.32 
•32 
•15 
•32 
•25 
. 11 
.18 
.18 
•29 
.04 
.18 
•15 
o. 18 
•32 
.18 
. 11 
.29 
•25 
.18 
.08 
•04 
. 11 
. 08 
0.74 
.88 
.62 
.62 
•57 
. 11 
.17 
•32 
. 08 
. 11 
•53 
1.48 
o- 46 
■32 
• 25 
•36 
.18 
. 22 
. 08 
. 11 
.29 
•03 
. 11 
.04 
o. 18 
.32 
.18 
•25 
.18 
.18 
. 11 
. 11 
. 08 
• 32 
. 11 
.04 
o. 04 
.18 
• 03 
• 25 
. IX 
.01 
Plot J. 
Plot M. 
Plot R. 
o. 74 
1.02 
•95 
.69 
•53 
•15 
.18 
•39 
. 08 
•53 
.88 
.64 
o. 46 
.46 
.18 
•59 
.18 
•32 
•25 
.46 
. 29 
.04 
•39 
• 15 
o. 46 
.46 
.18 
.18 
. 11 
• 25 
.18 
•32 
. 08 
.04 
. 11 
. 08 
1.02 
.88 
. 60 
.66 
o. 60 
.46 
•50 
•25 
.25 
•25 
.08 
•32 
•32 
. 11 
.18 
.04 
o. 46 
.18 
. II 
. x8 
. 11 
.18 
•15 
.46 
. 22 
.04 
.18 
.04 
Lost. 
. 11 
• 17 
. 11 
. 11 
.08 
1.02 
1.02 
.90 
. 81 
o. 46 
.46 
.38 
•39 
.18 
•44 
. 11 
•39 
•30 
. 10 
•15 
. 11 
0.32 
•74 
.18 
. II 
. II 
. 22 
•25 
•36 
.09 
. 20 
. 11 
. II 
0.18 
• 25 
. 11 
.08 
.14 
.08 
Period. 
Plot T. 
Depth.inches 
1914. 
September. 
October.. 
November.;.. 
December. 
_ 1915- 
January. 
February.. 
March. 
April. 
May. 
June. 
juiy. 
August. 
0-6 
6~i 8 
18-30 
I. 02 
0.74 
0.46 
I. 02 
.46 
.46 
I. IO 
•32 
•i 5 
I. 09 
•25 
. 11 
.88 
•25 
• i 5 
• 32 
.24 
• 25 
. 61 
•52 
. 22 
. 60 
•53 
•30 
. II 
■36 
. 18 
• 32 
.04 
.04 
• 71 
•25 
.18 
• 25 
.08 
.08 
30-42 
