2 so ENGINEERING ON THE FARM 



has a direct bearing on the quantity of water needed. It 

 has been found that there are wide differences in the require- 

 ments of different kinds of fruit trees and in the early and 

 later varieties of the same fruit. Citrous trees require more 

 water than trees which shed their leaves a part of the year. 

 Olive trees will bear fruit with less water than peach trees, 

 although the olive retains its leaves much longer than the 

 peach. Old trees that are bearing heavily usually require 

 more moisture than young ones. Shallow-rooted vegetation 

 may die from drouth, while deep-rooted plants will produce 

 a fairly good crop. Tonics, fertilizers, fungicides, and 

 insecticides are sometimes applied to trees to stimulate 

 their growth, when the only requirement is water. Drying 

 due to lack of water frequently gives the tree the appearance 

 of having been attacked by some disease, and this condition 

 may prevent proper bearing the following year. 



Humid climates. Climates that have an annual rainfall 

 of 20 inches or more are considered humid. If this rainfall 

 is evenly distributed throughout the growing season, there 

 will not be any need for irrigation, but the rain usually comes 

 intermittently, and during the summer rather long periods 

 may intervene between showers, which will check plant 

 growth. It is not so much the quantity of rain that falls, 

 but the time when it falls, that determines the need for irri- 

 gation. In Florida, where there is an annual rainfall of 

 60 to 70 inches, irrigation has been practiced extensively 

 and the demand for it is increasing. The same is true of 

 other states along the Atlantic coast. While the application 

 of water may not be necessary every year to prevent crop 

 failure or injury to plants, the fact that it is available is a 

 guarantee against loss, for a lack of water at the critical 

 period may greatly reduce the profits from truck and fruit 

 and affect not only the quantity of the product, but the 

 quality as well. While irrigation in the humid states has 

 not been found practicable for field crops, it more than 

 justifies its cost in gardens and on fruit farms. 



