982 
Journal of Agricultural Research 
Vol. XXXI, No. 10 
the stalk. Growth of ash in the seed conforms very well to the 
formula, and this is true also for the several elements of the ash. 
Some interesting comparisons may be made between the growth 
curves of the various constituents of the seed. Phosphorus and 
protein (nitrogen X 6.25) have the same value of K, and protein is 
directly proportional to the phosphorus of 7 days preceding. The 
curves for sulphur and fat also have some similarity, in that t x is 108 
for each, a considerably delayed value as compared with other 
constituents; and also, for each it is necessary to assume that the 
growth process was still in active progress at the last observation. 
The curves for all the data have been worked out to a first approxi¬ 
mation, 13 but there is no need to repeat all of them here. The data 
for dry matter and crude fiber in seed of sunflower and ear of corn 
are given, however, for the purpose of certain further comparisons 
of the two crops on the basis of the growth constants. 
DRY MATTER IN SEED AND EAR 
The percentage water content of plant tissues varies widely with 
maturity of the plant. Thus at the time of the first observation on 
the sunflower seed the water content was 86 per cent and at the last 
Fig. 6. —Growth of dry matter in seed of sunflower per acre. Time (t) is reckoned in days from date o- 
planting. Growth ( x) is expressed as a percentage of 1,450 pounds. Equation to curve: 
^ ii ^" 0 ’ 058 (< - 102) 
observation 15 per cent. There are obvious reasons for dealing with 
the dry matter as a measure of growth. The data for the seed of 
sunflower and ear of corn are presented in Figures 6 and 7, respect¬ 
ively. The course of growth, as measured by dry matter, conforms 
satisfactorily to the theoretical considerations. Considering the 
equations, we find the sunflower with a large value of K (0.058) 
13 Gaines, W. L., and Nevens, W. B. the sunflower as a silage crop, composition and yield at 
DIFFERENT STAGES OF maturity. HI. Agr. Exp. Sta. Bui. 268: 407-455. illus. 1925 
