Nov. 15, 1925 
Growth-Equation Constants in Crop Studies 
983 
and the corn with a small value of K (0.038), this agreeing in ^a 
general way with the hint offered by the second growth cycle 'of 
the stalk as the data were treated in Figures 4 and 5. Another 
difference in the curves is notable: In treating the growth in dry 
matter of the ear by the method used it is necessary to assume that 
growth had not reached its natural limit at the last observation. 
Such an assumption is not necessary for the sunflower data. This 
again is consistent with the treatment of the corresponding data o 
Figures 4 and 5. 
Fig. 7.—Growth of dry matter in ear of corn per acre. Time (t) is reckoned in days from date of plant 
ing. Growth (x) is expressed as a percentage of 6,000 pounds. Equation to curve: 
log eo^i"" 0,038 
CRUDE FIBER IN SEED AND EAR 
The course of development of crude fiber in the seed of sunflower 
(fig. 8) is practically identical with that of dry matter. This is 
partly a consequence of the fact that crude fiber constitutes a high 
and fairly constant proportion of the dry matter of the seed through¬ 
out the growth cycle. The per cent of crude fiber based on dry mat¬ 
ter lies within the range 31 to 39. 
The course of crude-fiber development in the ear of corn (fig. 9), 
however, presents a contrast to that of dry matter. The crude fiber 
of the ear is largely in the cob (about 85 per cent at maturity). 
Figure 9 may be presumed, therefore, to represent approximately 
the growth of the cob. On the basis of interpretation by the equa¬ 
tion, the crude-fiber growth cycle is completed, whereas it is not 
completed in case of dry matter. The apparent completion of the 
growth cycle of the cob contrasts also with the incomplete second 
cycle of Figure 5, taken to represent growth of husk and shank, 
if one were to speculate he might infer that the inherent growth 
limitations of the cob are a limiting factor in the maximum growth 
Obhary 
CESE/C INVESTIGATIONS. 
