CEREAL CULTIVATION WESTERN AREA 399 



plow 8 to 12 inches deep, between March 1 and 15. On 

 the California State Farm at Davis, 40 trials were made 

 of deep and shallow plowing for wheat and barley during 

 3 years, the former referring to depths of 7 inches or 

 over and the latter ranging from 3 to 5 inches : 



TABLE XII. RESULTS OF DEEP AND SHALLOW PLOWING 

 GRAIN. AVERAGE OF 40 TRIALS IN 3 YEARS 



FOR 



In Oregon, the depth of plowing recommended is 7 to 

 10 inches with a mold-board plow, and 10 to 11 inches 

 with a disk plow, which is frequently used in the Western 

 area. Steam disk plows in gangs are often employed on 

 large farms, though both steam power and the disk form 

 of plow are now less commonly used than formerly in 

 some localities (Figs. 126, 127). The Wyoming Experi- 

 ment Station recommends plowing to the depth of at 

 least 8 inches. 



427. Subsequent tillage for spring seeding. The 

 details of cultivation after plowing or disking, whether 

 for immediate seeding or in summer tillage, vary greatly 

 in different districts. 



After spring plowing for seeding the same spring, usually 

 there is no further treatment than 1 or 2 harrowings and 

 drilling the seed. It is in this case that the corrugated 



