62 POMOLOGY 



is available together with ample water, and in order to cor- 

 rect the over-vegetative condition any of several cultural 

 practices may be discontinued. The simplest plan might 

 be to seed the orchard down to grass if it is being tilled ; or 

 to discontinue the use of fertilizers and manures; to reduce 

 the number of cultivations; to discontinue the use of cover- 

 crops; or in some other way to reduce the nitrates and mois- 

 ture available to the trees until a better ''balance" is main- 

 tained. 



Under-vegetative and unfruitful trees, on the other hand, 

 require opposite treatment. The probability is that there 

 is a lack of nitrates and perhaps moisture in such cases, a 

 condition which has already been referred to (p. 58). This 

 situation is representative of more unfruitful orchards 

 than the over-vegetative ones cited above. Here also sev- 

 eral treatments may be applied: fertilization with some 

 quickly available nitrogenous materials; tillage; the use of 

 leguminous cover-crops; perhaps the ranging of poultry in 

 the orchard; or in some other way to improve the' mois- 

 ture conditions of the soil and to supply nitrates to the 

 trees. 



Again reverting to the proposal of Kraus and Kraybill, 

 the following outline may be suggestive of means of regu- 

 lating the growth behavior of trees. It illustrates an im- 

 portant point of their work, namely, that there is often a 

 double and apparently opposite effect of some orchard prac- 

 tices. In other words, it is not the method in itself which is 

 most important but rather the relationship of materials it 

 influences under varying circumstances, as indicated in the 

 following outline: 



