8 



MISC. PUBLICATION 99 2, U.S. DEPT. OF AGRICULTURE 



\4 M 



/vi \ 



mm 





4! 



10 



Figure 3. — Pelleted (upper) and nonpelleted (lower) seeds of crested wheat- 

 grass (left and center) and intermediate wheatgrass (right). The pellets 

 at left are coated with clay; those at center and right have a plastic -feldspar 

 coating. 



Effects of pelleting 



Seed damage by the coating process is low. Tisdale and Piatt 

 (1951) found only 8 percent of broken seeds in coated pellets of crested 

 wheatgrass. 



Germination of coated seeds is similar to that of nonpelleted seeds. 

 Tisdale and Piatt (1951) found a germination of 77 percent in the 

 laboratory and 83 percent in the greenhouse as compared to 85 percent 

 for nonpelleted seed. Gatherum (1951) listed 49 types of seed coat- 

 ings. Emergence as compared to nonpelleted seed was as follows: 

 10, lower; 1, higher; 38, not significantly different. Hull (1959) 

 compared the percentage of germination of two types of coated crested 

 wheatgrass seed and one type of coated intermediate wheatgrass 

 seed with nonpelleted seed from the same lots in a germinator and in a 

 greenhouse. Pelleting had no significant effect on germination. 

 Moomaw et at. (1954) found little difference in germination between 

 coated seed pellets and nonpelleted seed of five species of range 

 grasses. 



Pellet behavior 



Although coated pellets are less affected by wind than nonpelleted 

 seed, they are inferior to compressed pellets for airplane distribution. 

 The coated pellets fall slowly; and when they strike the earth, they 



