16 BULLETIN 1175, U. S. DEPARTMENT OF AGRICULTURE. 
low yield of all grain sorghums, with the lowest yields of kafirs 
obtained during the 8-year period. 
The seasonal distribution of rainfall in 1917 was very unfavorable 
for normal development of crops. The rainfall for April, May, 
June, and July was much below normal, while that of August was 
more than double that month's average. Evaporation for June and 
July was the highest recorded at this station for these two months. 
These conditions caused the sorghums to make a second growth in 
August and September, which prolonged the growing period until 
frost. Frost occurred two weeks earlier than the average date. In 
spite of poor distribution of moisture during the earlier part of the 
summer, average yields of grain were obtained from the milos, and 
high yields were obtained from the kafirs. 
The season of 1918 was dry. The rainfall of each month from 
April to September was below the average, with the exception of 
May, which was slightly above the average. The rainfall in June, 
July, and August w r as not sufficient to produce crops, and hot winds 
in these months were very detrimental to plant growth. As a con- 
sequence, low yields of ail grain sorghums and the lowest yields of 
the milos in the 8-year period w T ere produced. 
The 1919 season is an excellent example of a season with a com- 
paratively low rainfall during the months of June, July, August, and 
September, distributed in such a manner as to maintain crop growth 
and return high yields of grain sorghums. The seasonal precipita- 
tion, April to September, w r as 2 inches below the 8-year average, yet 
high yields of practically all grain sorghums were obtained. 
The seasonal precipitation of 1920 was 2 inches above the average 
and was fairly well distributed. One droughty period from July 10 
to August 10, during which no effective rains occurred, cut the yields 
of milos that were heading at that time. The yields of grain sorghums 
in general were high, and 1920 was an excellent season in the sorghum 
belt. 
The season of 1921 was very favorable for crop production. The 
seasonal precipitation was 3.5 inches above the average and was well 
distributed. Though the rainfall in April and May was below the 
average, that of the months of June, July, August, and September 
was above normal. There were droughty periods during the latter 
part of both July and August, but rains came before serious damage 
was done. The results were high yields of the important varieties 
of grain sorghum. 
VARIETAL EXPERIMENTS. 
The objects of the varietal experiments were to determine the 
adaptation and value of the different groups and of the more impor- 
tant varieties in each group. The varietal studies with grain sorghums 
were started in 1914, and the results for eight years are reported. 
The varieties and strains with which the work was started were 
obtained from the Amarillo Cereal Field Station, Amarillo, Tex., and 
were those which experiments at that station had shown to be best 
adapted to the sorghum belt, varieties of all groups of grain sorghums 
being included. The policy since these experiments were begun has 
been to discard those varieties and strains which prove to be of no 
economic value for this district and to add any new or promising 
variety or strain about which information is desired. In certain 
