2G 



BULLETIN 500, U. S. DEPARTMENT OF AGRICULTURE. 



per acre than on sod. This slight difference may be due to the fact 

 that, In general, less care is taken in irrigating orchards in mulch 

 crop, although to keep the mulch crop from clogging the furrows 

 often entails extra work. 



In Table XIV is given a cost summary for all irrigations. 



THINNING. 



Thinning the fruit from the trees is a practice followed by the 

 majority of growers. This operation is usually done in June or July, 

 most growers thinning during the latter part of June. Thinning 

 increases the size and color of the' remaining fruit, and if practiced 

 systematically eliminates in large measure the cull or poor fruit, thus 

 saving harvest labor. This operation is done by hand, either by 

 picking the apples or clipping them off with a thinning shears. The 

 low-headed trees are most frequently thinned. It is not customary 

 to thin branches which can not be reached from a stepladder. Apples 

 are left from 3 to 6 inches apart. Some growers thin the clusters 

 so that no two apples are borne on the same fruit spur. 



Condition of crop and variety of apple are the most important 

 factors influencing thinning. Some varieties, like Winesap, require 

 so much more thinning than others, such as the Arkansas Black, that 

 a general average of time required per acre for thinning is of little 

 practical significance in itself. Estimates were obtained from each 

 grower as to the number of trees a man would thin per 10-hour day, 

 and as to the percentage of his trees thinned. These estimates were 

 checked up with his estimate of the average time spent thinning 

 his orchard per year. The averages derived from these estimates 

 are shown in Table XV. 



Table XV. — Thinning practices and costs {125 ranches, western Colorado). 



County. 



Number 



of 

 records. 



Num- 

 ber of 

 records 

 of 

 thin- 

 ning. 



Per 

 cent 

 prac- 

 ticing 

 thin- 

 ning. 



Num- 

 ber of 

 trees 

 per 

 acre. 



Aver- 

 age 

 size of 



or- 

 chard 

 (acres). 



Trees 

 thinned 



in 10 

 hours. 



Per cent 



of 



trees 



thinned. 



Dis- 

 trib- 

 uted 

 hours 

 per 

 acre. 



Cost 

 per 

 acre. 



Mesa 



49 

 61 

 15 



41 

 45 

 6 



83.7 

 73.8 

 40.0 



70 

 78 

 71 



8.22 

 12.19 

 13.66 



10.89 

 16.45 

 13.85 



45.3 

 44.1 

 26.0 



24.36 

 15.42 

 5.35 



$6.09 



Delta 



3.86 





1.34 









125 



92 



73.6 



74 



10.81 



13.96 



43.45 



17.71 



4.43 







It will be seen from these figures that the more general the farm 

 the less tliinning is practiced. There is a decided drop in Montrose 

 County, where orchards as compared to those of Mesa are not given 

 a great deal of care. It is significant that the greatest proportion 

 of cull apples is found in Montrose. It will also be seen that the 

 larger the orchard the less time is spent thinning per acre, which 



