66 INTENSIVE FARMING 



expenditure of energy required to cultivate level 

 land. The same arrangement that lightens the 

 burden of cultivation helps at spraying time 

 and at harvest time. 



The indicator which may be relied upon to 

 decide whether or not the trees are receiving 

 an adequate supply of food is the length of the 

 annual growth. If this growth is six inches or 

 less the tree is on short rations. If it is eight 

 inches or more the tre is well nourished, and if 

 it is twelve inches or more on trees in full bear- 

 ing the growth is excessive, and the system of 

 cultivation should be modified to suit the re- 

 quirements of the case. Too little growth is 

 as much to be avoided as too much; both result 

 in crop failure. 



In the Eastern United States too little 

 growth may be expected on poor soils long in 

 sod. In the Northwest this condition arises 

 from clean culture and an exhaustion of the 

 limited nitrogen supply. Many of the areas 

 devoted to orcharding in Oregon and Wash- 

 ington are of volcanic origin. The soils have 

 an abundant supply of potash and phosphoric 

 acid, but a limited supply of nftrogen. The trees 

 make a fair growth during their early life and 

 come into bearing early. As fruit production 

 increases the growth of the plant decreases 



