GRAIN-SORGHUM EXPERIMENT.- IX OKLAHOMA. 
39 
three more varieties of grain sorghums were added that year to the 
date-of-seeding experiments — Dawn kalir C. I. Xo. 340), feterita 
C. I. No. 182), and Blackhull kaoliang (/. I. Xo. 310). In 1921 
Reed karir (C, T. Xo. 628) was added, to obtain data on its behavior 
as compared with the other sorghums when sown on different dates. 
The block of land used for date-of-seeding experiments is all pre- 
pared before seeding the earliest plats. The plats to be sown on each 
date are worked down before seeding, usually with a spring-tooth 
harrow, and the seed is drilled deep enough to reach moist soil. 
Land for the later dates is kept free from 'weeds by working with a 
spring-tooth or disk harrow when necessary. The date-of-seeding 
plats have varied in size from G to 10 rows'. 44 inches apart and 132 
feet long, one row equaling 0.0111 I one-ninetieth) acre. When any 
border effect between plats is apparent the outside rows of the 
adjoining plats are discarded. 
The agronomic data for the date-of-seeding experiments are pre- 
sented in Tables 16 to 20. Table 21 is a summary of the yields of 
all varieties included in the date-of-seeding experiments. 
DWARF YELLOW MILO. 
Table 16 shows the agronomic data for Dwarf Yellow milo in the 
date-of-seeding experiments. This table shows that the stands ob- 
tained from the mid- 
dle of April and first 
of May seedings have 
been thinner than 
those obtained from 
the sowings made on 
the later dates. 
These poor stands 
have been due to the 
cool, moist condition 
of the soil, which 
causes the seed to de- 
cay rather than ger- 
minate, a fact which 
should be considered 
in early seeding. The 
other dates have 
been fairly compar- 
able in any year and 
between the different years. In most years the thin stands of the 
earlier dates have been compensated by suckering, so that in general 
the differences in stands are not a limiting factor of yield. Figure 5 
shows the relation of the date of seeding to the percentage of suckers 
produced. 
The total growing period has been longest from the mid-April seed- 
ing in each of the 5 years. The extremes in the length of total 
growing period were 169 days for the middle of April seeding in 1917 
and 97 days for the mid-June seeding in 1919. The average number 
of days in the total growing periods for the six dat<-- of seeding is 
shown graphically in Figure 6. It is apparent that the number of 
days required from seeding to maturity decreases as the date of 
seeding advances from the middle of April to the middle of June, 
^/oo 
§ so 
N fiPR/L /5 MfiY/ MftY/5 JUNE f JUNE/ 5 JULY/ 
Fig. 6.— Diagram showing average number of days from seeding to 
ripening for Dwarf Yellow milo sown on different dates in The 
date-cf-seeding experiment during the 5-year period from 1917 to 
1921, inclusive. 
