THE AVOCADO 37 



tion are as large at four years of age as non-irrigated trees. at 

 six years. Their larger size enables them to yield commercial 

 crops earlier than non-irrigated trees. 



In California it is the general practice to irrigate avocados 

 in the same manner as citrus fruits. The amount of water 

 necessary for maximum development varies considerably on 

 different soils, but during the first few years a thorough irrigation 

 every ten days during the dry season is not too much. 



The importance of an abundance of moisture in the soil at 

 the time the fruit is setting has already been mentioned in 

 the discussion of the climatic requirements of the avocado. 

 Several crop failures in Florida have been blamed on unusually 

 dry weather during this period. A drought probably does 

 little harm if it occurs when the trees are just beginning to 

 bloom, but if it continues the flowers are likely to drop and the 

 crop to be a failure. This has been the experience with 

 Trapps when grown on deep sand ; on heavy soils, which are 

 more retentive of moisture, the danger is less. 



In order to avoid crop failures from this cause, the grower 

 should certainly be prepared to irrigate at the time the fruit 

 is setting. In southern Florida this is usually in March and 

 April. When a prolonged dry spell occurs just at this time, as 

 is sometimes the case, two or three thorough irrigations, a 

 week apart, may suffice to save a considerable amount of fruit. 



In California, if the soil is allowed to become too dry during 

 the hot summer months, young trees are frequently given a 

 setback from which they are slow to recover. This has been 

 observed in Florida as well, particularly on deep sandy soils. 



The method of applying water varies in different regions. 

 In California the basin system is commonly used, especially 

 when the number of trees to be irrigated is small. Basins 

 should be filled with coarse strawy manure to serve as a mulch. 

 In many orchards the trees are irrigated by the furrow system 

 which is used with citrus fruits, the soil being cultivated after 



