GRAIN-SORGHUM EXPERIMENTS IX OKLAHOMA. 15 
the total number of heads produced, the quotient being multiplied 
by 100 to express the result as a percentage. 
The total growing period as given in this bulletin is the number 
of days from seeding to maturity. The vegetative period is the 
time from seeding until the heads have appeared. The date of 
heading is figured as the average between the date of the first head- 
ing (when most of the heads are showing through the boot or when 
earlier heads are fully exserted) and the date of full heading (when 
the heads of the main stalks are fully exserted). The fruiting period 
is the time from the date of heading until the kernels are ripe. The 
height of the plants is the average of measurements taken at several 
points (usually 10) in the plats. 
The plats are harvested with a corn binder, leaving a stubble 
about 6 inches high. The bundles are shocked on the plat and are 
left to cure for one or two months before threshing. When ready 
to thresh, the bundles are hauled to the scales and weighed. Before 
threshing, the heads are cut from the bundles by means of a large 
knife mounted on a frame. Threshing is done with a small separator. 
In threshing the sorghums, it was found necessary to remove all 
but one concave and slow down the cylinder to prevent too much 
cracking of the grain. The grain as it comes from the separator 
contains varying quantities of trash and is fanned before grain 
yields and bushel weights are determined. The yields are figured 
on the basis of 60 pounds to the bushel for the kafirs and 58 pounds 
for other varieties. 
ENVIRONING CONDITIONS. 
A brief summary of the seasonal conditions for each of the eight 
years 1914 to 1921, inclusive, is given to help interpret the results 
obtained in these experiments. 
The 1914 season was unfavorable for high yields. A rain of 1.96 
inches on May 1, together with 13 light showers distributed through 
the remainder of the month, brought the rainfall for May up to the 
average. The seed germinated and the crops started well in this 
month. June was unfavorable for crop growth, a rain of 0.61 inch 
on the 15th being the only precipitation in the month, which was 
marked also by high evaporation. On July 6 a good rain fell, fol- 
lowed by a dry period of about a month. The rainfall for August 
was below normal, and half of the rain came after the principal 
varieties were ripe. The rainfall for September was but 0.56 inch 
divided in six light showers. Yields of grain sorghums were low. 
The season of 1915 was wet for the sorghum belt. The rainfall 
for the months from April to September, inclusive, was 26.8 inches, 
and this was well distributed. At no time in the growing season 
did the crops lack moisture, so that high yields of most of the grain 
sorghums resulted. 
Conditions very unfavorable for high yields prevailed during the 
1916 season. While the seasonal precipitation was slightly above 
normal, this was due entirely to heavy rains during one month, June. 
The rainfall for the other five of the growing months was below the 
average, no precipitation whatever occurring in July. The six weeks 
of drought following the rainy June was responsible for the low yields. 
Evaporation for the season was the highest on record at this station. 
The sorghums headed and fruited during the drought, and the rain- 
fall of August was not enough to help production. The result was a 
