May 14,1917 
Soil Nitrogen and Nutrition of Citrus Plants 
193 
of the nitrogen added. With the exception of soil B, there is an increase 
in total nitrogen following the addition of the clover, which in soil U 
amounts to 32.54 per cent of the nitrogen added. 
Table V .—Percentage of nitrogen added to soils in dried blood and green manures recov¬ 
ered as ammonia and nitrates after six weeks* incubation; also percentage gain or loss of 
nitrogen added. July 16, 1914 
[Results expressed as milligrams of nitrogen per ioo gm. of soil] 
pwi u 
Materials added. 
Nitrogen 
in ma¬ 
terial 
added. 
Nitro¬ 
gen as 
ammo¬ 
nia re¬ 
covered 
in 6 
weeks. 
Per¬ 
centage 
of nitro¬ 
gen as 
ammo¬ 
nia re¬ 
covered. 
Nitro¬ 
gen as 
nitrate 
recov¬ 
ered in 
6 weeks. 
Per¬ 
centage 
of nitro¬ 
gen as 
nitrate 
recov¬ 
ered. 
Nitro¬ 
gen re¬ 
main- 
ingin 
soil 
after 6 
weeks. 
Gain or 
loss in 
nitrogen. 
Percent¬ 
age of 
of nitro¬ 
gen 
gained 
or lost. 
Dried blood (i per cent). 
Red clover (2 per cent). 
Alfalfa (2 per cent). 
Buckwheat (2 per cent). 
137 * 20 
40.14 
57* 20 
33* 12 
25* 04 
1.96 
2- 24 
1.40 
18. 25 
4.88 
3*92 
4*23 
49.40 
14* 56 
17.64 
8.12 
36.00 
36*27 
30.84 
24.52 
108.60 
53* 20 
75* 60 
35 *oo 
—28.60 
13* 06 
18. 40 
1. 88 
—20.85 
32 .54 
32.17 
5* 68 
PLOT P 
Dried blood (1 per cent). 
137* 20 
33 * 04 
24.08 
44 * 80 
32. 65 
119* 30 
—17.90 
— 13*05 
Red clover (2 per cent). 
40.14 
x. 40 
3*49 
16. 24 
40.46 
50.69 
10. 55 
26. 28 
Alfalfa (2 per cent). 
57.20 
1. 68 
2.94 
19.04 
33 * 29 
70.50 
13 * 30 
23*25 
Buckwheat (2 per cent). 
33*12 
.84 
2. 54 
2. 52 
7.61 
33*90 
.78 
2.36 
PLOT B 
Dried blood (1 per cent). 
X37* 20 
50.68 
36.94 
x.68 
X. 22 
71.40 
-65.80 
—47.96 
Red clover (2 per cent). 
40.14 
2. 24 
5* 59 
12.04 
30. OO 
40.14 
.00 
. 00 
Alfalfa (2 per cent). 
57. 20 
2. 24 
3* 92 
14-00 
24.48 
51.80 
~ 5*40 
— 9*44 
Buckwheat (2 per cent). 
33*12 
X. 68 
. 5*07 
X. 13 
3* 38 
25.22 
— 7.90 
—23* 85 
PLOT H 
Dried blood (1 per cent). 
137* 20 
51.40 
37* 46 
5 * 76 
4. 20 
98. 70 
—38. SO 
—26. 06 
Red clover (2 per cent). 
40.14 
1. 68 
419 
12.88 
32.09 
44.10 
3 * 96 
9 * 87 
Alfalfa (2 per cent). 
57* 20 
2. 24 
3 * 92 
X5* 12 
26.43 
53*90 
— 3*30 
~ 5*77 
Buckwheat (2 per cent). 
33*12 
1.12 
3*38 
1.40 
4 * 23 
23.10 
—10. 02 
—30. 25 
VIRGIN SOIL 
Dried blood (1 per cent). 
137* 20 
52.64 
38*37 
x. 68 
X. 22 
8l. 20 
—56. OO 
—40.8c 
Red clover (2 per cent). 
40.14 
x- 68 
4.19 
xo. 64 
26. 51 
49-00 
8. 86 
22.07 
Alfalfa (2 per cent). 
57. 20 
1.68 
2 .94 
14 * 56 
25. 46 
6l. 60 
4.40 
7* 6g 
Buckwheat (2 per cent). 
33* 13 
x. 12 
3*38 
x. 12 
3.38 
32. 20 
— .92 
— 2. 78 
The addition of 2 per cent of alfalfa caused only a small increase in 
the ammonia content of the soil, but a marked gain in nitric nitrogen, 
from 24.48 to 33.29 per cent of the nitrogen in the alfalfa being converted 
into nitrates. Considerable gains in total nitrogen were secured in soils 
U and F and a small gain in the virgin soil, but soils B and H showed a 
small loss of nitrogen. 
Buckwheat caused a somewhat smaller increase in the ammonia con¬ 
tent of the soil than did red clover or alfalfa. The percentage of nitrogen 
recovered from buckwheat as nitrates is very much smaller than the 
