BEEEDING MILLET AND SOBGO FOE DBOUGHT ADAPTATION. 3 



tion may be practiced and the largest possible quantity of water stored 

 in the 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 15 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 REQUHtEMENT. 



A low water requirement x 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 



i "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, H, . L. The 

 water requirement of plants. 1.— Investigations in the Great Plains in 1910 and 1911. U. S. Dept. Agr. ; 

 Bur. Plant Indus. Bui. 284, p. 7, 1913. 



