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. 
Fic. 5.—Cultivating by means of the spring-tooth harrow on one of the larger valley ranches. 
TaBLeE XVII.—Average time and cost per acre for various cultural operations in 75 
orchards under clean-cultural management in Yakima Valley. 
! 
Crew. | 
| Acres | Cost 
Implement. in10 | per 
Mee dee hours. | acre. 
; 
PAG Wise A a ae re a a ee ee Ee en 1} 2} 1.58] $3.487 
Dist: Vir oOw sete foes Aare ee A Se cee ee ee eee ee 1 | 2 5.18 | 1.062 
Sprine-toobmharrow = 2-2 ee oe a ee ee ee 1 | 2 | 7.30 | . 754 
Spike-tooiintarrows 2 fb 20 a SSE 2 PPS ee Ee Oe Ee eee 1 2} 9726) 2554 
6-(oot Cultivator: 22522 8 oe ee ee Ne eae oe 1 | 2 t= eto . 710 
Pl Oates a5 2: 2S Se ee onic a ee eee ee ee ee eee 1 2 | 8.55 | . 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 soul. 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 
