340 The Commercial Apple Industry 



When trees of good yielding varieties are brought to 

 bearing age, careful record should be kept of annual yields, 

 particularly acre yields. One hundred barrels of commer- 

 cial fruit to the acre is a good average although trees well 

 cared for can often be made to average 200 barrels under 

 normal growing conditions. If an orchard is only 

 averaging from 50 to 100 barrels to the acre (many do not 

 average 50 barrels to the acre), care should be taken to 

 find out the limiting factor. Light yields may be due to 

 a lack of nitrogen or other element in the soil, to lack 

 of pollination, or to poor orchard management. Improper 

 pruning, thinning, spraying or soil management are as 

 often the cause of low yields as the variety of the trees, 

 the season or natural fertility of the soil. Many theories 

 are advanced relative to the development of fruit-buds 

 and fruiting wood, but it is difficult to generalize on this 

 subject. 



Good orchard management is for the purpose of secur- 

 ing heavy yields and no study as to the cause of high or 

 low yields would be complete without a consideration of 

 practically every orchard operation. In analyzing the 

 cause of low yields, one should consider first soil fertility. 

 The growing of leguminous cover-crops or the application 

 of such fertilizers as nitrate of soda may be necessary to 

 maintain healthy normal growth of the trees. Thinning 

 will tend to stimulate annual bearing as well as greatly to 

 increase the amount of market quality fruit of any year. 



Pruning should be considered in relation to its effect 

 on yields. Many advocate summer pruning for fruit. 

 Under certain conditions it probably stimulates fruit pro- 

 duction, but it has not met with wide favor generally. 

 Moderate annual pruning in the dormant season is the 



