Nov. 29, 1915 
Ash Composition of Upland Rice 
361 
but it was impossible to wash them white. The analyses show that the 
material which could not be washed off was probably finely divided ferric 
oxid. The percentages of iron found in the ash of the roots ranged from 
5.36 to 8.48. This was obviously due to iron contamination from the soil. 
It was evident, however, that this was a selective contamination chiefly 
of iron particles, as the ratio of F^Og to A 1 2 0 3 to Si 0 2 in the soil was about 
1 to 1.5 to 6. 1 * Thus, a contamination of the soil as such which would 
have increased the iron content 6 per cent would have raised the silica 
36 per cent and the alumina content 9 per cent. As the high iron content 
of the root ash is thought to be due to selective contamination from the 
soil, the results for iron are not reported. The percentages of the other 
constituents, except possibly silica, could not have been materially 
affected by soil contamination. 
Table III .—Ash composition of the roots and of the whole rice plant aboveground 
Percentages in carbon-free ash of— 
Material analyzed. 
Whole plant 
aboveground. 
Do. 
Do. 
Do. 
Do. 
Do. 
Roots. 
Do. 
Do. 
Do. 
Do. 
Do. 
Age of 
mate¬ 
rial. 
Silica 
(SiOa). 
Time 
(CaO). 
Magne¬ 
sia 
(MgO). 
Iron 
(Fe203>. 
Potash 
(KaO). 
Soda 
(NaaO). 
Phos¬ 
phoric 
acid 
(P 2 O 5 ). 
Sulphu¬ 
ric acid 
(SO3). 
Chlorin 
(Cl*). 
Days . 
18 
56. 88 
2. 21 
3. 69 
°* 75 
22. 91 
I. 75 
7- 94 
O. 24 
26 
5 6 - 34 
2. 40 
4.24 
•35 
17. 28 
9.76 
6.65 
5-81 
4-47 
48 
62. 56 
1* 73 
3* i 1 
. 21 
14. 66 
9- 57 
4. 00 
4. 41 
4. IO 
73 
67. 24 
1. 89 
3- 07 
. 28 
i5- 54 
4- 13 
3- 19 
3.6l 
4*90 
103 
73- 29 
2. 30 
3-09 
. 28 
7.46 
7. 60 
3- 87 
2.94 
3. 22 
123 
73-43 
1. 77 
2- 57 
.29 
12. 33 
4- 43 
3. 21 
2.86 
2. 90 
18 
42. 28 
3. 82 
9. 68 
22. 
2. 10 
7. 33 
26 
35- 62 
3 - 73 
8. 42 
ic. 46 
17. 23 
/ 0*3 
8. 11 
C. 48 
48 
46. 06 
3* 01 
4- 36 
21.03 
f 0 
6. 32 
4.98 
8.06 
2. 30 
73 
60. 21 
2. 84 
4* 3° 
15. 24 
3- 74 
3* 02 
6-73 
I. 92 
103 
6i- 57 
2. 76 
3-84 
IO. 83 
4. 42 
2. 46 
6. 67 
•99 
123 
64. 70 
4* 3 1 
3- 05 
12. 47 
1. 19 
2. 63 
6.87 
i* 45 
The percentages of iron in the ash of the whole plant aboveground 
showed but little variation after the sharp drop from the 18- to the 26- 
day-old sample. 
Leaving out of consideration the 123-day-old sample, the composition 
of which was probably influenced appreciably by the leaching of rain, it 
can be seen that during the growth of the plant the percentages of lime 
and magnesia in the ash tended to remain constant, the silica increased, 
the phosphoric acid and sulphuric acid decreased, the potash, somewhat 
irregular, tended to decrease, and the soda was irregular. The variations 
in the percentages of soda are somewhat peculiar, the increase from the 
18- to 26-day-old sample being out of all proportion to changes in other 
constituents. Soda in the ash of the roots, however, increased to an 
1 Iron is much higher in the finer soil separates than in the coarser. (Failyer, G. H., Smith, J. G., and 
Wade, H. R. The mineral composition of soil particles. U. S. Dept. Agr. Bur. Soils Bui. 54, 36 p. 1908.) 
