U4 
EFFECT OF DATE OF SEEDING ON CORN. 9 
TABLE 3.—Total height and average daily increase in height of corn at the Arlington Ex- 
perimental Farm, near Washington, D. C., when planted on different dates in 1915, 
1917, 1919, and 1920. 
Height of stalks 
Emer- inches). 
gence 
Date of seeding. a8 Ras i 
verage 
faouay Total. daily. 
. increase. 
IATDPs TO sone ces ES eS ne 63 75.6 1. 20 
WED? 2) Parma See oe BCE Ee = aie eee mea ate | 51 86. 4 1.69 
TIPERD 21 a Sec wisn i RE Oe RE ce a a ee es ie IST 45 88. 8 1.97 
Rese aE ES 4 Dye 5) nme ho ec es geek eee 43 76.8 1.79 
EFFECTS ON DEVELOPMENT. 
The number of days from emergence to first silks decreased as the 
date of seeding was delayed from April to July. The number of 
days from emergence to ripening also decreased except in the case 
of the July seedings. These showed an increase as compared with 
the June seedings. Development to the silking stage was more 
rapid as the date of seeding was delayed. The plants from the 
April seeding required 63 days from emergence to reach the same 
stage of development which those from the July seeding attained 
in 43 days. 
The duration of the pollen-shedding period depended upon the 
degree of inherent variation within the variety, the lack of uni- 
formity in coming up, the amount of suckering, the variation in 
the fertility of the soil, and weather conditions. How these various 
factors might influence the duration of pollen shedding in a variety 
is evident and need not be treated in detail. Except under unusual 
conditions, the experiments indicate that the duration of this period 
is longer in plants from the earlier seedings than in those from the 
later seedings. The average for the plants from the April seedings 
was 22 days; May, 19 days; June, 18 days; and July, 17 days. 
CORRELATION OF EFFECTS. 
It is of interest to know how closely the difference in number of 
days between the dates of seeding corresponds with the differences 
between dates of emergence, dates of first silking, and dates of 
| ripening. The average results from all the experiments are shown 
in Table 4. 
As the date of seeding was delayed the differences in the time of 
emergence, silking, and ripening more nearly approximated those 
in the date of seeding. 
In the comparison of April and May seedings a difference of 32 
days in time of seeding represents a gain of 14 days in time of ripen- 
ing. May 20, however, is later than the usual date of seeding in 
