SUDAN GRASS AND RELATED PLANTS. 93 
maps show that the successful production of Sudan grass 1s correlated 
with high temperatures during the growing season and to a less 
extent with rainfall. 
USE AS A CATCH CROP. 
Sudan grass will be widely grown as an emergency hay crop in 
much the same manner as millet. As a means of overcoming a 
threatened shortage in the supply of hay required to carry the 
farmer’s live stock through the winter, Sudan grass is fully as good 
as millet. (Fig. 15.) The growing season js short, the quality of 
the hay is very good, and the yields of Sudan grass are usually 
higher than millet yields. Millet in the North and sorgo (sweet 
20004. 496: 
WTF wef LL. 
60, 
Y 7g 
eee 
3 mee) i 
LF Axe 
69. 
Fic. 14.—Outline map, showing by States and other indicated geographic divisions (1) the average length 
(in days) of the growing season or frost-free period, (2) the mean temperature (in degrees F.) of the grow- 
ing season, (3) the normal annual rainfall (in inches), and (4) the percentage of success with Sudan grass 
grown in different sections, as reported by several thousand farmers who received trial packages of seed 
from the United States Department of Agriculture in 1915 and 1916. Frost is likely to occur any month 
of the year in the western section of Wyoming (marked with an asterisk). 
sorghum) in the South have been the most popular catch crops. 
A comparison of these two crops with Sudan grass is presented in 
Table IT. 
Table II shows that millet is equal or superior to Sudan grass in 
the northern Great Plains and that it yields about the same in the 
timothy and clover belt if only one cutting is considered in the yield 
of both crops. In the southern Great Plains Sudan grass yields 
much more than millet. Sweet sorghum grown in cultivated rows 
or in drilled or broadcasted seedings outyields both Sudan grass and 
millet, but the hay is coarse and unsuitable to handle with a fork. 
The aftermath or second growth of sorghum is not as safe to pasture 
as that of Sudan grass, and none of the millets make sufficient second 
