362 
Journal of Agricultural Research 
Vol. V, No. 9 
equally great extent from the 18- to 26-day-old sample. Variations in the 
percentages of potash in the ash of the plant aboveground were for the 
most part accompanied by similar variations in the ash of the roots. The 
percentages of soda in the ash seem, as a rule, to fluctuate inversely as 
the percentages of potash. This is in accord with results showing that 
soda can to a small extent replace or exercise part of the functions of 
potash. 1 
In the ash of the roots lime, magnesia, phosphoric acid, and chlorin all 
decreased fairly regularly with the age of the sample. 
In Table IV are given the percentages of the ash constituents present 
in the dry matter of the roots and of the whole plant aboveground. 
Tabee IV .—Ash constituents in dry substance of the roots and the whole rice plant above¬ 
ground 
Material analyzed. 
Whole plant above¬ 
ground . 
Do. 
Do. 
Do. 
Do. 
Do. 
Roots. 
Do. 
Do. 
Do. 
Do. 
Do. 
fc <£> 
> 
to 
1 
If 
i 
111 
8*1 
O 
& 
< 
PlH 
Days. 
18 
18.7 
26 
20. 2 
48 
14. 6 
73 
20. 9 
*°3 
25.8 
123 
36*2 
18 
26 
48 
73 
103 
123 
Percentages of ash constituents in dry substance of plant. 
Carbon-free ash. 
Silica (SiOs). 
/*\ 
0 
3 
1 
Magnesia (MgO). 
CO 
1 
ft 
Potash (K2O). 
/N 
s 
GJ 
5 
Phosphoric acid 
(P2O5). 
S u 1 p h uric acid 
(SOs). 
ys 
N 
s 
1 
6 
Nitrogen (N). 
17-75 
10.10 
0-39 
0.65 
0 .133 
4.07 
0.28 
1.41 
1.64 
14.97 
8.43 
.36 
•63 
• 052 
2. 59 
i- 47 
1.00 
.87 
0. 67 
4.02 
22. 21 
13.89 
•38 
.69 
. 048 
3- 26 
2.13 
.89 
.98 
.91 
1.89 
17. 96 
12.07 
•34 
•55 
• 051 
2. 79 
• 74 
•56 
•65 
.88 
1.87 
14.99 
10.99 
•35 
.46 
.041 
1.12 
1.14 
• 58 
•44 
.48 
•94 
14. 96 
10.99 
. 26 
.38 
.044 
1. 85 
.66 
.48 
•43 
•43 
• 84 
II. 71 
4-95 
•45 
I -13 
2. 64 
. 86 
%. 28 
. 80 
1.47 
• 77 
• 5 2 
1.48 
7. 82 
3.60 
.24 
•34 
1. 64 
•49 
•39 
.63 
.18 
•95 
8.32 
5- 01 
.24 
•36 
1.27 
• 3 i 
•25 
• 5<5 
. 16 
1.09 
8.09 
4.98 
. 22 
• 3 i 
.88 
•36 
. 20 
•54 
.08 
• 75 
5 - 53 
3-58 
.24 
■ 17 
.69 
.07 
•15 
.38 
.08 
.66 
In the first four samples the percentages of ash in the dry matter of 
the plant aboveground varied inversely as the percentages of dry matter 
in the green plant, and, as noted above, the percentages of dry matter 
seemed to be lower during the periods of greater precipitation. Thus, 
with dry weather preceding the sample, the percentage of dry matter in 
the green plant was high and the percentage of ash low. 3 An average 
of several crops of rice grown at different times to eliminate the effect of 
temporary weather conditions would doubtless show gradually increasing 
percentages of dry matter in the green plant and gradually decreasing 
percentages of total ash in the dry matter. 
1 Wagner, Paul. Forschungen auf dem Gebiete der Pflanzenernahrung. I. Theil: Die Stickstoffdungung 
der Landwirthschaftlichen Kulturpflanzen. p. 231, Berlin, 1892. 
Hartwell, B. L., and Pember, F. R. Sodium as a partial substitute for potassium. In R. I. Agr. Exp. 
Sta. 21st Ann. Rpt., 1907-1908, p. 243-247. 1908. 
2 This is probably owing to the fact that during wet weather the growth of new leaves and tissues is 
especially active, while in dry weather organic matter is formed more rapidly than mineral matter is 
absorbed. 
