58 POMOLOGY 



It also means that it is essential to study the ways in which 

 various cultural practices affect these materials. That 

 abundant storage of carbohydrates is associated with non- 

 fruitfulness as truly as under-storage, is here brought out 

 in contradistinction to the opinions of some other workers. 

 An interesting example of lack of balance of these materials 

 and the results obtained when such balance is restored is 

 noted in the case of an experimental orchard in Oregon.^ 

 The apphcation of quickly available nitrogenous fertilizers 

 gave almost immediate and conspicuous results in an or- 

 chard which was unfruitful and making very little growth 

 extension. The suggested interpretation of these results 

 was to the effect that there was probably a condition of 

 large amount of carbohydrates in the trees and a low supply 

 of nitrate in the soil, and when this latter was increased the 

 carbohydrates could be utilized in the production and devel- 

 opment of fruit. This is an interesting explanation of a 

 very common experience in orchard fertilizer experiments. 

 The theory, that the addition of sufficient nitrates and mois- 

 ture to balance an accumulation of starch and other stor- 

 age materials within the tissues of the plant, serves as a nec- 

 essary accompaniment of growth and bud formation, can 

 find ready acceptance with those who have seen such or- 

 chard experiments. Fruitf ulness would be decreased if plants 

 were reduced from III to II but in the case cited they were 

 shifted from IV to III with consequent fruitfulness. 



It has been suggested also that top- as well as root-prun- 

 ing of trees upsets the balance of the carbohydrate-nitro- 

 gen-moisture combination, which appears to influence so 

 markedly the formation of fruit-buds. The reserve mate- 

 rials of the tree are reduced by top-pruning (see discussion 

 in Chapter V), resulting in their limitation relative to the 



^ Lewis, C. I., and G. G. Brown. Rept. Hood River Branch Exp. Sta. 

 (Ore.). 1916. 



