10 BULLETIN 1014, U. S. DEPARTMENT OF AGRICULTURE. 
the vicinity of Washington, and this gain in time of maturity does 
not represent the gain of early over normal seedings. In this con- 
nection, some comparisons of early seedings made in April with 
seedings made at more nearly the normal date of seeding ey 1 to 
15) will be of interest. 
TaBLE 4.—Dvufferences in the dates of seeding and the resulting differences in the dates 
of emergence, silking, and ripening of corn in experiments conducted at the Arlington 
Experimental Farm, near Washington, D. C., during the 6-year period from 1915 to 
1920, inclusive. 
| ; | Number of days difference in— 
Average dates | Seedings com- Y f dat 
of seeding. pared. SES OI Appear- 
| Seedings. eater ance of Ripening. 
Bence.” | first silks. 
oy ace 27 |MApril and May..| 1915,1916,1917, and 1920. . 32 “25 14 14 
Maye). Se =: 5s May and June...| 1915,1917,and 1920......,.| 38 - 30 22 23 
SaaS SSG \yune and July...| 1915,1917,1918, and 1920... 28 | 27 96;| G15 16 
Data from such comparisons made in 1917, 1919, and 1920 are 
shown in Table 5. In 1917 the experimental plats were located on 
fairly uniform upland. The seeding made on April 12 was on land 
that had been cropped to soy beans the previous year, followed by 
rye that had been plowed under preparatory to seeding corn. The 
plat seeded on May 14 was on land that had been in sod the previous 
year. The two plats, however, were sufficiently similar to permit 
reliable comparisons in respect to the characters dealt with in Table 
5. In 1919 and 1920 all the seedings were made in adjacent or 
neighboring plats on uniform reclaimed river land that had been 
previously cropped to corn. 
The results presented in Table 5 show that in the season of 1917 
plants from seedings made a month earlier than normal were about a 
week earlier in silking than plants from normal seedings. In 1919 
the gain in earliness was less than a week. In 1920 a difference of 17 
days between seedings resulted in a gain of 7 to 9 days in the time of 
silking: The differences in the time of silking correspond fairly 
closely with the differences in the time of ripening and can be deter- 
mined more readily and with a greater degree of accuracy. The data — 
available indicate that the differences at the time of ripening are 
slightly less than at the time of silking. 
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