Nov. 29,1915 
Ash Composition of Upland Rice 
363 
On account of the fluctuations in the amount of total ash, it is thought 
that the percentages of the various ash constituents in the dry matter 
are less significant than the composition of the ash, which would be un¬ 
affected by temporary weather conditions. 
The plants were not analyzed at frequent intervals while ripening; 
nevertheless, the preceding work throws some light on the question of 
loss of mineral elements at this time. In Table V are given the absolute 
weights of the ash constituents in one plant at 103 and at 123 days. 
Table V .—Gain or loss of ash constituents by the rice plant aboveground during last 
20 days of growth 
Weight of ash constituents (in grams) in one whole plant aboveground. 
Material analyzed. 
Age of material. 
Carbon-free ash. 
1 
Silica (SiOg). 
i 
•1 
Magnesia (MgO). 
/*s 
1 
/■"s 
s 
I 
] 
Soda (NasO). 
Phosphoric acid 
| (P2O5). 
Sulphuric acid 
(SO3). 
Chlorin CL). 
| Nitrogen (N). 
Whole plant aboveground.. 
Days. 
103 
4.427 
3-245 
0.102 
0.137 
O.OI2 
0*330 
0-337 
0.172 
0.277 
0.130 
0.143 
Do. 
123 
5-306 
3- 896 
.094 
•i 37 
.015 
• 655 
-m 
.235 
. 170 
.297 
.152 
• *54 
It is evident that the aboveground part of the plant lost considerable 
soda between the last two periods. The roots also must have lost con¬ 
siderable soda, as the percentage of soda in the dry matter of the roots 
dropped from 0.36 per cent at 103 days to 0.07 per cent at 123 days, 
, while the absolute weight of roots could have increased but little during 
this interval. The results do not show whether there was any loss of the 
remaining ash constituents. It is only apparent that, as compared with 
103 days, the plant aboveground contained at 123 days the same or a 
slightly greater quantity of all ash constituents except soda. It is, of 
course, possible that between 103 and 123 days there might have been an 
increase followed by a loss of the other ash constituents. The marked loss 
of soda was more than compensated for by a gain in potash. The in¬ 
creases in the other elements were relatively slight, and the apparent losses 
of lime and phosphoric acid are without significance when the probable 
errors of the weights of the plant at the two periods are considered. 
DISCUSSION OF RESULTS 
It is unnecessary to detail all the changes in ash composition that 
occurred during the growth of the plant, as these are evident in the tables. 
In common with similar studies of many other plants the percentages 
of potash, phosphoric acid, and sulphur in the ash and of nitrogen in the 
dry matter decreased with the age of the plant, while the silica increased. 
The results show that while the iron content of the ash of the whole 
plant varied but little with the age of the plant, the percentage of iron in 
