158 The Commercial Apple Industry 



is too steep to cultivate and where clean cultivation would 

 result in bad washing. The natural vegetative growth 

 supplemented by fertilization in some instances and occa- 

 sional cultivation about trees serves to maintain the fertil- 

 ity of these soils. 



The disadvantages of the sod-mulch system are: (1) 

 reduces yields; (2) reduces vitality and tree growth; (3) 

 provides harbor for mice, insects and diseases; (4) has 

 tendency to encourage general neglect; (5) reduces soil 

 aeration; (6) sheds rain. 



In all cost-production studies, the question of yield 

 appears as the critical factor. It is not the acre cost of 

 operation, but the barrel or box cost of production that 

 determines profit. If the yield can be increased, the cost 

 of production is usually materially decreased. Eecords 

 taken by the writers show that in general yields are re- 

 duced under the sod-mulch system. 



While the sod-mulch may be depended on to return 

 humus to the soil and commercial fertilizer may maintain 

 fertility, the lack of cultivation will undoubtedly be felt, 

 and as a general rule trees in sod-mulch have less vitality 

 and make less growth than those which are cultivated. 



Some growers, notably one very successful grower in 

 western New York and many in southern Ohio, use the 

 sod-mulch system very profitably. It can not be con- 

 demned under all conditions but it unquestionably tends 

 to encourage general neglect of the orchard. The grower 

 with the sod orchard is not brought into such intimate 

 touch with his trees as the one who practices more intensive 

 culture and who is working about among his trees every 

 few days. Furthermore, the sod furnishes a harbor for 

 mice, insects and diseases. 



