250 SORGHUMS 



regions, as intense sunshine, dry air, and hot winds. Certain varie- 

 ties, especially the sweet sorghums, flourish in regions of heavy rain- 

 fall, but even these are quite drought resistant. The Kafirs and 

 Durras, however, probably reach their best development under only 

 moderate rainfall (ten to twelve inches for the growing season) and 

 are very resistant to dry, hot climates. 



How Sorghums Resist Drought. Actual test has shown 

 sorghums to require less water than many other crops. This is de- 

 termined by growing plants in large cans and keeping a record of 

 the water used. The water used is generally expressed in the num- 

 ber of pounds required to produce one pound of dry weight. With 

 some of the common crops, the following data have been secured by 

 Briggs and Shantz at Akron, Colorado. (Bureau of Plant Industry 

 Bulletin 284.) 



Water Requirements of Grains 



Pounds of water to Percentage 



produce one pound compared 



Crop of dry weight with wheat 



Oats 614 122 



Barley 539 106 



Wheat 507 100 



Corn 369 73 



Sorghum 306 60 



Millet . 275 54 



While sorghum requires less water than the small grains, it is 

 not very different from corn. Yet sorghum is more drought re- 

 sistant than corn, which leads to the conclusion that it must also 

 have other qualities to consider. It appears to be helped by its 

 ability to remain alive, but without growing, through long periods of 

 drought, apparently without injury, and at once recover and grow 

 rapidly when rains come. If sorghum, at any stage of growth, is 

 subjected to long, severe drought, the outer leaves roll up about the 

 plant, protecting the younger leaves and growing top. It may re- 

 main in this state for weeks, with little or no growth, and quickly 

 recover and continue growth when rains come. On the other hand, 

 corn, if submitted to such a drought, would in a short time be killed 

 or, at least, be severely injured. In fact, it is said that any check 

 to the corn plant during its growth will cause permanent injury. 

 This is generally true of all crops, but sorghums suffer least of all. 



