BKEEDIFG MILLET AND SOEGO FOE DBOUGHT ADAPTATION. 3 
tion may be practiced and the largest possible quantity of water stored 
in tbe soil for the use of the following crop. The strain of millet 
(Dakota Kursk) described in this bulletin may be cut for hay in from 
70 to 75 days after planting and will mature seed in 90 days. The 
early strain of sorgo (Dakota Amber) described here matures seed in 
a period of 95 to 100 days from the date of planting and is sufficiently 
mature for forage in 1 5 days less time. 
DROUGHT ENDURANCE. 
The most important adaptation to drought presented by sorgo is 
its ability to revive quickly after a period of drought. The crop may 
cease growth for a considerable time during a dry period, but if a 
heavy rain occurs it will then revive and make a rapid growth. This 
was the case at Akron, Colo., in 1910, when a dry period during June 
and July allowed only a limited growth of the crop and caused the 
plants to produce seed heads earlier than usual. A rain of 2.8 inches 
on August 4, however, caused a vigorous secondary growth, so that 
the plants produced additional seed heads, which were fully two 
weeks later in maturing than the seed first formed. 
Millet shows much less drought endurance than sorgo, but it com- 
pares favorably with the small grains and corn. 
LOW WATER REQUIREMENT. 
Alow water requirement 1 is an important factor in the adaptation 
of plants to conditions of drought. In this respect millet and sorgo 
are preeminent among drought-resistant crops. At the Belle Fourche 
(S. Dak.) station in 1912 millet had a water requirement of 240, as 
compared with 460 for wheat and 735 for alfalfa; that is, the quan- 
tity of water which was required to produce 1 ton of dry matter 
(hay and grain) in a mature millet crop would produce only 1,043 
pounds of dry matter (hay and grain) in the form of a mature wheat 
crop and only 654 pounds of dry matter in the form of alfalfa hay. 
In experiments conducted at Akron, Colo., Briggs and Shantz found 
that the water requirement of sorgo is only slightly higher than that 
of millet. The water requirement of millet and sorgo is further 
discussed elsewhere in this bulletin. 
CLIMATIC CONDITIONS. 
Crop production in the Great Plains is largely dependent upon the 
amount of rainfall which occurs during the growing season of the 
crop. By means of summer fallowing a part of the precipitation of 
one season may be stored in the soil for the benefit of the following 
* "The term 'water requirement' is used ... to indicate the ratio of the weight of water absorbed by 
a plant during its growth to the weight of dry matter produced." (Briggs, L. J., and Shantz, U . L. The 
water requirement of plants. 1.— Investigations in the Great Plains in 1910 and 1911. U. S. Dept. Agr. ; 
Bur. Plant Indus. BuL 284, p. 7, 1913. 
