Apr. 16,1917 
Absorption of Nutrients 
83 
It is evident that under the special conditions of these tests the absorp¬ 
tion of phosphorus and nitrogen obey practically the same law. 
EXPERIMENT VII.—RICE WITH ONE-HATE THE ROOTS IN POTASSIUM-FREE 
SOLUTION 
It was thought that the figures for the relative absorption of potas¬ 
sium by plants partially and completely supplied with potassium might 
vary somewhat from the similar figures for nitrogen and phosphorus, 
since, as is well known, sodium can to a small extent replace or supple¬ 
ment a deficiency of potassium in the plant, while a deficiency of nitrogen 
or phosphorus can not be supplemented by other mineral elements. 
In this experiment the complete acid solution and the potassium-free 
solutions shown in Table I were used, while ferric tartrate was the source 
of iron. Eight flasks were taken as a unit and the units duplicated for 
each treatment. The plants were grown for 20 days in 200-c. c. flasks 
and 20 days in 500-c. c. flasks. Solutions were changed 10 times during 
the experiment. Experimental data are shown in Tables XIV and XV. 
Table XIV. —Growth of rice in Experiment VII 
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. 
Potassium-free.... 
Do. 
Potassium-free... 
Complete. 
/ 1-8 
l 9-16 
/17-24 
\25-32 
/33-40 
\41-48 
Gm. 
57*25 
55*86 
281.43 
282.93 
316. 60 
299* 40 
Gm. 
11.02 
10. 25 
41*05 
39* 23 
43* 12 
42.42 
Gm. 
ho. 64 
J-40.14 
}42* 77 
/ 225 
\ 229 
/ 438 
l 437 
/ 501 
l 5i4 
252 
247 
467 
449 
498 
469 
Gm. 
r 1*64 
} 5*47 
} 5*92 
Gm. 
1.84 
5* 70 
5* 5 1 
•327 
.278 
. 267 
Complete. 
.do. 
Table XV. —Potash and soda absorbed by rice in Experiment VII 
Flask No. 
Potash (KsO). 
Soda (Na 2 0 ). 
In dry stalks 
and leaves. 
In dry roots. 
Absorbed by 16 
plants. 
Absorbed per 
gram of roots. 
In dry stalks 
and leaves. 
In dry roots. 
Present in 16 
plants. 
Absorbed per 
gram of roots. 
& 
| 
< 
1 
3 
■3 
A 
I-16 
I 7“32 
33-48 
Per cent. 
0. 45 
3 * 90 . 
5-25 
Per cent. 
0*43 
1. 09 
2. 76 
Per cent. 
0 * 43 
1*35 
2. 76 
Gm. 
Gm. 
Per cent. 
I. 66 
.78 
■ 71 
Per ct. 
I. 24 
I. 48 
.88 
Per ct. 
I. 24 
i *39 
.88 
Gm. 
Gm. 
1.639 
2. 498 
O . 288 
. 219 
0. 4733 
•4043 
O. 0424 
•0354 
Assuming that plants 33 to 48 were normal in growth and composition, 
it can be seen that the partial-potassium plants (17 to 32) had 4 per cent 
greater ratio of roots to tops, absorbed 0.66 of the normal amount of 
