26 



BULLETIN 614, U. S. DEPARTMENT OF AGRICULTURE. 



plowed every year, 8 every other year, 5 every three years, and 1 

 every four years. Of the 43 who practiced clean cultivation, the 

 usual practice of 15 was to begin the annual cultivation with the 

 plow, 7 with the disk harrow, 11 with the spring-tooth harrow, 4 

 with the spike-tooth harrow, 4 with a cultivator, and 2 with mis- 

 cellaneous implements. Of the 15 who plowed annually, 13 plowed 

 in the spring and 2 in the fall. 



Fig. 5. — Cultivating by means of the spring-tooth harrow on one of the larger valley ranches. 



Table XVII. — Average time and cost per acre for various cultural operations in 75 

 orchards under clean-cultural management in Yakima Valley. 



Implement . . 



Crew. 



Acres 

 in 10 

 hours. 



Cost 



Man. 



Horse. 



acre. 



Plow 





2 

 2 

 2 

 2 

 2 

 2 



1.58 



5.18 



7.30 



• 9.26 



7.75 

 8.55 



S3. 487 





1.062 





.754 



Spfke-tooth harrow 



.594 

 .710 



Float 



.644 











The making of the deep dust mulch not only aids in the conservation 

 of moisture but makes it possible for irrigation water readily to pass 

 through the soil. As soon as the soil becomes packed and cracks 

 open from improper care, irrigation water will not be taken up so 

 readily. As_soon as soil conditions permit, cultivations are made 

 after each irrigation, usually until the middle of the summer or until 

 the weight of the fruit bears the limbs down so as to interfere with 



