16 



BULLETIN 614, U. S. DEPARTMENT OF AGRICULTURE. 



Table IX. — Average yield per acre, 1910-1914, inclusive, for 120 orchards in Yakima 



Valley. 





North Yakima dis- 

 trict. 



Zillah district. 



North Yakima and 

 Zillah districts com- 

 bined. 



Year. 



Number Av< 3rage 

 of i yield in 



records packed 

 recoias. boxes _ 





Number 



of 

 records. 



Average 

 yield in 

 packed 

 boxes. 



1910 



20 

 30 

 51 

 62 

 64 



617. 1 

 277.9 

 617. 3 

 354.6 

 590.5 



24 464. 7 



44 

 63 

 99 

 116 

 120 



534.0 



1911 



33 

 48 

 54 

 56 



216.8 

 591.3 

 328.6 

 452.3 



246.0 



1912 



604.7 



1913 



1914 



342.5 

 526.0 







There is a difference in the number of estimates considered in 

 different years, yet the figures presented reflect the tendency to 

 alternate bearing, as well as the effects of weather conditions. 



The age of the trees has a marked bearing on the yield for these 

 districts. Some varieties of apples in the Yakima Valley bear a few 

 apples at the age of 5 years. However, in arriving at the average yield 

 for the valley only the yields from orchards aged 7 years and over are 

 considered. The majority of orchards from which records were taken 

 were between the ages of 9 and 15 years at the time of this study. 

 Each orchard is given the same weight and the acre is used as a basis 

 of comparison. All yields were taken from orchards representitive 

 of the district, so as to make the data comparable. There is a gradual 

 increase in the yields of trees from the time they are 6 years of age. 

 (See Table X.) 



It will be noted that the yield per tree increases rapidly with the age 

 until the tree reaches 9 years of age and that thenceforward the in- 

 crease is more gradual. 



There were not enough records of orchards over 12 years of age to 

 furnish reliable figures. 



Table X. — Yield per acre from trees of different ages in the Yakima Valley. 



Number of estimates. 



Average from total . 



Age of 

 trees. 



Yield in 

 packed 

 boxes. 



175 

 311 

 350 

 453 

 454 

 469 

 505 



Trees per 

 acre. 



75. 66 

 73.50 

 73.82 

 73.71 

 74.32 

 72.12 

 73.97 

 73.81 



Boxes per 

 tree. 



2.32 

 4.23 

 4.74 

 6.14 

 6.10 

 6.51 

 6.83 



The size of the orchard appears to have considerable influence on 

 the yield throughout the districts. (See Table XI.) Small orchards 

 have more trees per acre than the larger ones, and as a rule the ranch 



