12 CIRCULAR 491, U. S. DEPARTMENT OF AGRICULTURE 



rain falls and weeds are destroyed by tillage. Seedings unduly de- 

 layed in the spring are often damaged by torrential rains and rapid 

 drying of the surface soil. Seeding when the ground is dry, "dust- 

 ing in," has been successful in a few instances, but the chances of 

 total failure are too great to recommend this method. 



Canada wild-rye, bluestem (western wheatgrass), and Texas blue- 

 grass respond to cool weather, and therefore usually thrive best when 

 sown early in the spring or in the fall (fig. 3). Many other grasses 



Figure 3. — Grasses sown in the fall of 1937 at Woodward, Okla. : a, Crested 

 wheatgrass: b. btuestein (western wheatgrass) ; c. Canada wild-rye: d, Virginia 

 wild-rye ; e, blue grama. The last has an excellent stand, but the plants were 

 too small to show well in the illustration. 



less resistant to cold may be sown advantageously in the fall when con- 

 ditions are especially favorable. Seedings made early enough in the 

 fall to survive the winter in good condition usually contain very 

 few weeds the following spring, whereas spring seedings generally 

 become infested with weeds no matter how carefully the land is pre- 

 pared in advance. Fall seeding should likely be protected from 

 blowing by planting a row of Sudan grass every 48 inches, unless 

 the seedbed already contains sufficient wind-resisting stubble. 



Although medium-early spring planting appears to be best for 

 most grasses adapted to the region, preliminary results obtained at 

 Woodward indicate that fall seedings may be successful under cer- 

 tain conditions. Most of the 33 species sown on September 12, 1936. 

 emerged satisfactorily and 16 survived the winter. Fair to excel- 

 lent stands were likewise obtained in 1937 from 32 out of 34 species 

 and strains sown on September 5, 13 out of 14 sown on September 6, 



