GRAIN-SORGHUM EXPERIMENTS IX OKLAHOMA. 
43 
rear the July 1 date made the highest grain yield. The 5-year 
average yields for the different dates arc given in Table 16. The 
highest yielding plat of Dwarf Yellow milo in 1921. the June 15 
seeding, is shown in Plate IV. Figure 2. 
1 N \' T( (\l »5 ' X X fl( i^ nj ' X X J <\l rg "3 ' X x' <Tj r\< ») ' X X l\j (\j "J 'w^H) 'w^ 1 ^ S <\ ^ if X) 
$ s9sze/c /**y uu/ve yJUE-y august September octobe/z bushels fez siceE 
Fig. 11.— Diagram showing (1) at bottom, daily precipitation fin inches) from April 1 to October 31, 1921; 
2 -ntral portion, length of growing (solid bars) and fruiting (open bars) periods of six successive 
seedings of Dwarf Yellow milo: (3) at top. mean temperature (in degrees F.) by 5-day periods from 
April 1 to October 31; (4,) at right, acre yield (in bushels) from each of the six seedings. 
There appears to be a critical period in the development of the 
milo crop, which extends from the time the head is forming in the 
boot until the seeds have formed. Should this stage fall during a 
dry period, the yield will be reduced. To show the relation between 
the dates of seeding, the growing periods, rainfall, and yields, Figures 
Iff/u ve •--•=>j _ . fna. votes 
■ n i l... -■ - ^ 
AUGUST <Se/>r£/<t&Etf OCTO££:# 
Fig. 12.— Diagram showing (1) at bottom, average precipitation (in inches) by 5-day periods from April 
1 to October 31 during the five years from 1917 to 1921, inclusive; (2) central portion, average length 
of growing (solid bars' and fruiting (open bars) periods of six successive seedings of Dwarf Yellow milo 
during this - at top, average mean temperature (in degrees F.) by .5-day periods from 
April 1 to October 31 during the five years from 1917 to 1921, inclusive; (4) at right, average acre yield 
(in bushels > from ea?h cf the six seedings in the 5-year period. 
7 to 11 are presented. The dates of first heading are given instead 
of the full heading dates, as the former show more nearly the begin- 
ning of the supposed critical period in the development of the milo 
plant. Figure 12 shows the average data for the 5 years, the rainfall 
and temperature being given by 5-day and 6-day periods averaged 
