82 
Journal of Agricultural Research 
Vol. IX, No. 3 
Table XII. —Growth of rice in Experiment VI 
Nutrient solution. 
Flask 
No. 
Weight of stalks 
and leaves. 
Number of 
roots. 
Average oven- 
dry weight 
of roots. 
Ratio 
of 
roots 
to 
tops. 
A-flasks. 
B-flasks. 
Green. 
Oven- 
dry. 
Av¬ 
erage 
oven- 
dry. 
A- 
flasks. 
B- 
flasks- 
A- 
flasks. 
B- 
flasks. 
Phosphorus-free... 
Do. 
Phosphorus-free.. 
Complete. 
/ 1-8 
l 9-16 
/1 7-24 
\25-33 
/33-40 
I41-48 
Gm. 
5 - 53 
5 - 94 
279 - 07 
269. 01 
281. 28 
284.12 
Gm. 
1.67 
i- 75 
39-58 
39 - 94 
38. 22 
38- 50 
Gm. 
} i- 7 i 
f 39 - 76 
[38.36 
f 128 
l 132 
/ 595 
\ 647 
/ 550 
l 534 
144 
i 35 
263 
275 
301 
285 
Gm. 
} 0. 70 
} 7-98 
} 6.26 
Gm. 
0. 78 
3-86 
3-28 
I 
-865 
. 298 
• 249 
Complete. 
.do. 
Table XIII. —Phosphoric acid and nitrogen absorbed by rice in Experiment VI 
Flask No. 
Phosphoric acid (P2O5). 
Nitrogen (N) 
in dry stalks 
and leaves. 
In dry 
leaves and 
stalks. 
Absorbed 
by 16 
plants. 
Absorbed 
per gram 
of roots. 
I-16 
17-32 
33“48 
Per cent. 
Gm. 
Gm. 
Per cent. 
I. 49 
3-«s 
3 - 9 2 
O. 87 
i- 39 
o- 3459 
• 5332 
0.0896 
■ 0559 
If we assume that plants 33 to 48 were normal, 17 to 32, with one-third 
their roots in the complete solution, made a normal growth, had a 20 
per cent higher ratio of roots to tops, absorbed 0.65 of the normal amount 
of phosphorus, and absorbed 1.60 times the normal amount of phosphorus 
per gram of roots. 
Decreasing the number of roots in the complete solution had about the 
same effect on phosphorus absorption that it did on nitrogen absorption— 
that is, it decreased the total amount of phosphorus absorbed and in¬ 
creased the phosphorus absorbed per gram of roots. The fractions of 
the normal amount of phosphorus absorbed by the plants with one-half 
and one-third their roots in the complete solution were, respectively, 0.76 
and 0.65. These figures are in good agreement with similar factors of 
0.76 and 0.55 for nitrogen absorption by plants with one-half and one- 
fourth of their roots in the complete solution. Per gram of roots, how¬ 
ever, the partial-phosphorus plants increased their phosphorus absorp¬ 
tion less than the partial-nitrogen plants increased their nitrogen absorp¬ 
tion. This was due to the fact that growths made by the partial- and 
complete-phosphorus plants were about equal, while the partial-nitrogen 
plants made less growth than the complete-nitrogen plants. 
The fact that plants with only part of their roots in the complete 
solution made about the same growth as the normal plants, although 
they contained considerably less phosphoric acid, shows that the normal 
plants absorbed considerably more phosphorus than they needed. 
