138 POMOLOGY 



of the country, this type of soil constitutes a serious handi- 

 cap to fruit-growing as well as to the production of other 

 crops. Fruit plants vary considerably in their suscepti- 

 bility to alkali conditions. Loughbridge ^ has made a care- 

 ful study of this problem as shown in the table on page 137. 



"The (apple) tree is quite sensitive to alkali salts, and 

 their effects on the foliage of the tree were veiy marked. The 

 Jonathan seems to be more sensitive than the Duchess." 



The other fruits observed showed that when the trees 

 are affected by alkali soil conditions, the newer Hmbs are 

 more or less bare except for a tuft of leaves on the terminal, 

 the leaves are small, yellowish or blackish in appearance, 

 and the trees are barren of fruit. 



Observations and data cited show that "the suscepti- 

 bility of the wine (grape) varies according to variety, and 

 that while some are tolerant of very large amounts of car- 

 bonate of soda and common salt, others succumb to the 

 effect of far less of each." 



Hilgard ^ says, in discussing deciduous orchard trees, 

 "Of these, strangely enough, the almond seems to resist 

 best. The peach is more sensitive, the apricot does fairly 

 well. Plum trees are nearly as resistant as peaches, but 

 sometimes suddenly begin to fail when beginning to bear; 

 the fruit appears normal on the outside for a time, but the 

 pit fails to form, being sometimes flattened out like a piece 

 of pasteboard; and the fruit fails to mature. Apples are 

 rather sensitive; pears considerably less so, doing well even 

 when the outside bark around the root crown is blackened 

 by alkali. The olive is quite resistant, the fig less so." 



121. Drainage. — As stated in paragraph 114, the natural 

 drainage of the orchard land is of the greatest importance 

 in maintaining a healthy and long-lived tree. If the soil is 



1 Loughbridge, R. H. Calif. Agr. Exp. Sta. Bull. 133. 1901. 



2 Calif. Agr. Exp. Sta. Bull. 128. 1900. 



