16 BULLETIN 760, U. S. DEPARTMENT OF AGRICULTUEE. 
Table X. — DisJdng. 
District. 
Number 
of 
records. 
Per cent 
of total 
records. 
Acres 
disked 
per farm. 
Times 
disked. 
Hours of labor per 
acre. 
I abor 
cost per 
Man. 
Horse. 
acre. 
25 
8 
8 
31 
IS 
20 
63.44 
62. SS 
7S.3S 
1.15 
1.S8 
1.38 
1.1S 
1.25 
1.05 
6.47 
8.28 
7.30 
SO. 89 
O-mnrrl 
1.09 
Salinas 
.95 
Two types of disk were used, the single action and the double 
action. The latter type has two sets of disks, one set in front of the 
other and so adjusted that the front set throws the soil out while 
the rear set throws it in, thus leaving the ground smooth. 
Fig. 7. — A cross-kill roller. The method of cunstruetiun not only permits this imple- 
ment to break clods, but it is also well fitted to firm the loose surface and secure 
the proper texture for a first-class seed bed. 
The width of implements used varied from 8 to 12 feet. Four men 
in the Los Angeles and one each in the Oxnard and Salinas districts 
did this work with a tractor. 
ROLLING. 
BEFORE PLANTING. 
The type of roller employed in preparing the seed bed ranged from 
the smooth-drum roller, either wood or steel, to the clod crusher or 
" cross-kill " (see fig. 7) , as it is commonly called. The cross-kill con- 
sists essentially of a series of narrow, toothed rings, attached to a 
shaft or axle. This implement not only breaks up clods and pul- 
verizes the soil, but also serves to pack loose soil. (See Table XL) 
