78 
Journal of Agricultural Research 
Vol, IX, No. 3 
Table VII .—Nitrogen and phosphoric acid absorbed by rice in Experiment III 
Flask No. 
Nitrogen 
(N) in dry 
stalks and 
leaves. 
Nitrogen (N) in dry 
roots. 
Nitrogen 
(N) ab¬ 
sorbed by 
16 plants. 
Nitrogen 
(N) ab¬ 
sorbed per 
gram of 
roots. 
Phospho¬ 
ric acid 
(P2O6) in 
dry stalks 
and 
leaves. 
A-flasks. 
B-flasks. 
Per cent. 
Per cent. 
Per cent. 
Gm. 
Gm. 
Per cent. 
1-16 
I. 03 
93 
93 
17-32 
4*35 
1. 38 
2.41 
O. 6124 
0. 306 
I. 50 
33-48 
4. 49 
1.47 
2. 60 
■ 6344 
*341 
i* 55 
49-64 
4 * 55 
2*35 
2*35 
.8277 
. 211 
1. 63 
65-80 
4 * 5 2 
2*35 
2-35 
■9093 
. 208 
1. 60 
A comparison of plants 49 to 64 with 65 to 80 shows that, when all the 
roots of the plants were in the complete solution, doubling the nitrogen 
in the solution had no effect on the ratio of roots to tops, the nitrogen 
. content of the plants, nor the amount of nitrogen absorbed per gram of 
roots. The slight increase in the weight of tops for 65 to 80 and the 
consequent increase in the total amount of nitrogen absorbed is of doubt¬ 
ful significance, as this increase is no greater than the variation between 
duplicates of the same lot. 
A comparison of plants 17 to 32 with 33 to 48 shows that doubling 
the nitrogen in the solution, when the plants had only half their roots in 
the solution, had no effect on the growth of tops, but lowered the ratio 
of roots to tops, very slightly increased the total amount of nitrogen 
absorbed, and noticeably increased the amount of nitrogen absorbed 
per gram of roots. It is evident from these comparisons that, with the 
ordinary complete solution, the absolute amount of nitrogen supplied 
was sufficient for all the plants, and the previous results obtained were 
not due to a scarcity of nitrogen. 
It follows from the preceding comparisons that doubling the nitrogen 
in the solution did not enable the partial-nitrogen plants to approach 
appreciably nearer the maximum nitrogen absorption (the amount of 
nitrogen absorbed by plants with all roots in the complete solution), 
although it did enable them to absorb more nitrogen per gram of roots. 
These facts are more evident from the following calculations: Plants 17 
to 32 absorbed 0.74 as much nitrogen as 49 to 64, had 22 per cent greater 
ratio of roots to tops, and absorbed 1.45 times as much nitrogen per gram 
of roots, while plants 33 to 48 absorbed 0.77 as much nitrogen as 49 to 
64, had 13 per cent greater ratio of roots to tops, and absorbed 1.62 
times as much nitrogen per gram of roots. 
EXPERIMENT IV.—RICE WITH THREE-FOURTHS THE ROOTS IN NITROGEN- 
FREE SOLUTION 
It was important to see whether the rate at which the roots absorbed 
nitrogen could be still further increased by decreasing the number of 
roots in the complete nutrient solution. Accordingly in this experiment 
one lot of plants was grown with approximately three-fourths of its 
