358 
Journal of Agricultural Research 
Vol. V, No. 9 
The plants were watered only a few times, during an occasional dry 
spell, and made an excellent growth. The growing period was from 
June 15 to October 16, during which time the weather conditions were 
fairly uniform, with high temperature and humidity. The average 
monthly mean temperature ranged from 77.2 0 in June to 79 0 F. in 
October. The monthly precipitations from June to September were, 
respectively, 10.90, 11.98, 11.67, and 8 22 inches. There were, however, 
some dry spells of a week or 10 days that apparently affected the plants; 
note of this is made below. 
At 18 days the plants were thinned from 40 to 29 in each cylinder, at 
which number they were kept during growth. The 11 plants removed 
from each cylinder at this time served for the 18-day-old sample, while 
for the 26-day-old sample 6 cylinders were cut; for the 48-day-old sam¬ 
ple, 5 cylinders; and for the succeeding samples, 4 cylinders each. As it 
was impossible to remove the roots completely from the heavy clay soil, 
the weight of the roots is not recorded. The roots were removed, how¬ 
ever, as completely as possible for analysis. 
In preparing the samples for analysis each leaf and stalk was washed 
individually immediately after cutting to guard against loss of mineral 
matter by leaching. Under such conditions there was probably a cer¬ 
tain loss of mineral matter from withered leaves, but no appreciable loss 
from the green leaves. However, this is practically of little importance, 
as the conditions of washing, while thorough, were no more severe than 
those to which the plant would be subjected by rainfall. Even digesting 
the leaves in cold water for 15 minutes extracted little mineral matter 
from green leaves. Forty-five gm. of green rice leaves previously washed 
on the plant were stirred up with 1 liter of distilled water. The water on 
evaporation yielded a residue of 0.008 gm. of mineral matter, part of 
which was due to minute leaf hairs broken off in the stirring; 9 gm. of 
withered leaves soaked for 15 minutes in 500 c. c. of water left a residue 
of 0.057 g m * of mineral matter. 
The analytical methods employed were essentially those of the Asso¬ 
ciation of Official Agricultural Chemists, 1 with a few exceptions. Prepa¬ 
ration of the ash was by the optional method, igniting over a very low 
flame without calcium acetate and leaching when necessary. Iron was 
determined colorimetrically with potassium thiocyanate, this method 
being preferable to titration with potassium permanganate for the small 
amounts present. 
ANALYTICAL- RESULTS 
In Table I are given the data on the weight and composition of a single 
plant with respect to withered leaves, etc., at each period of sampling. 
The weights of the plants were, of course, accurately determined, the 
probable error of the weights and percentages of dry matter merely show- 
1 Wiley, H. W., et al. Official and provisional methods of analysis, Association of Official Agricultural 
Chemists. U. S. Dept. Agr. Bur. Chem. Bui. 107 (rev.), 272 p. t 13 fig. 1908. 
