Nov. 15, 1925 
Growth-Equation Constants in. Crop Studies 
985 
growth capacity, the constant being 2.7 times that of corn. Com¬ 
paring dry matter in seed and ear, corn has much the greater capacity, 
the constant being 6.3 times that of the sunflower. Or we may com- 
K 3 the ratio of dry matter in seed or ear to crude fiber in stalk and 
that the ratio for corn is 17 times the ratio for the sunflower. 
As a cultivated crop, corn is evidently much better adapted to the 
production of maximum yields of valuable food or feed stuffs than is 
the sunflower. Breeding and selection may serve to improve the 
sunflower, but with its apparent inherent handicap of high vegetative 
and low reproductive development, it has little prospect of ever being 
a competitor of corn under conditions which permit the growing of 
corn. 
log 35<p^“°.047 (*“95) 
SUMMARY 
Data on the growth of the sunflower 11 and of com from Bulletin 
175, Indiana Agricultural Experiment Station are analyzed (following 
x 
Robertson 15 ) by application of the formula log = K (t — tt) , in 
Ji x 
which x represents growth accomplished at any time, t. The 
constants A, K, and A/K of this equation are regarded as of definite 
significance in connection with crop studies. The constants serve to 
give numerical expression to the course of growth changes in the crop 
and should be of value in supplementing the usual data of final crop 
yield. As between the sunflower and corn crop data studied, pro¬ 
nounced difference is shown, particularly with reference to the vegeta¬ 
tive and reproductive growth cycles. 
14 Gaines, W. L., and Nevens, W. B. the sunflower as a silage crop, composition and yield at 
different stages OF maturity. Ill. Agr. Exp. Sta. Bui. 268: 407-455, illus. 1925. 
m Jones, W. J., and Huston, H A. composition of maize at various stages of its growth. Ind. 
Agr. Exp. Sta. Bui. 175: 599-630, illus. 1914. 
Robertson, T. B. the chemical basis of growth and senescence. 389 p., illus. Philadelphia and 
London. 1923. 
