SUDAN GRASS AND RELATED PLANTS. 27 



to some money crop, such as corn, and allow the Sudan grass to 

 benefit by the residual effect, which is usually noticeable for two or 

 three years after the manure has been applied. 



DATE OF SEEDING. 



Like other plants of the sorghum family, Sudan grass must not be 

 seeded until the soil is warm. A large number of the failures with 

 this grass can be attributed directly to early planting, especially in 

 the northern part of the Sudan grass region. In South Dakota the 

 spring is usually cold and backward and seedings made by farmers 

 in the early part of May have often been unsuccessful. During the 

 same years, however, good crops have been grown at the experiment 

 station at Redfield, S. Dak., by planting about June 1 (fig. 16). 



Fig. 16. — Sudan grass 4 feet tall and not yet headed at the Redfield (S. Dak.) Field Station, August 10, 



1915. 



Sudan grass has frequently withstood light frosts, but a frost of any 

 severity is likely to injure the young plants materially. A good rule 

 is to sow this grass from two to four weeks after the normal date for 

 planting corn. Experimental data on this subject are presented in 

 Table III. 



Table III shows that in regions from 30° to 35° north latitude 

 the earlier dates are best, but that good yields may be expected from 

 seedings made at any time between April 1 and June 15. The 

 maximum hay yields were obtained from seedings on April 1. 



In the middle section of the United States, approximately between 

 35° and 40° north latitude, it is usually safe to sow at any time be- 

 between May 1 and July 1. There is no decided optimum date, 

 although June 1 gave a slightly higher average yield at the eight 

 stations where tests were made. 



