396 HORTICULTURAL MANUAL. 



the edges. About four inches of sand is covered over the 

 bottom of the cavity to prevent baking when water is 

 applied and to lessen the evaporation. The V-shaped 

 troughs are made long enough to reach from one tree to 

 another and are set one at a time on small iron supports 

 made for the purpose. The water runs into a cavity until 

 it is filled, when another is added to reach the next tree. 

 Enough of the troughs are needed for one row. In water- 

 ing the next row the troughs are brought over one at a 

 time as wanted. In the East the spaces between the 

 excavations are covered with some leguminous cover-crop, 

 usually the sandy vetch. In a very dry time the water is 

 permitted to run after the excavations are filled for a few 

 minutes at each tree. After the inexpensive plant is 

 established, the cost of watering each tree twice during 

 the season when the fruit is less than half grown and 

 again when two thirds grown was estimated by a number 

 of orchardists at eight cents. In the arid States this kind 

 of watering would do little good. But to bridge over a 

 dry period in the humid States, it secures a good crop of 

 perfect fruit, when the unwatered trees prove nearly a 

 failure. Even in Florida, with an average rainfall of over 

 sixty inches, irrigation has been largely practised in orange 

 orchards, to bridge over the dry periods and also to save 

 the garden crops and tobacco. In this case the water is 

 pumped from wells by gasoline pumps into large cypress 

 tanks, from which it is distributed over the comparatively 

 level surface by iron pipes to which hose is attached. 



In Illinois, Wisconsin, Iowa, and other drift-soil States 

 of the West, the subsoil favors the economical use of water 

 with after culture to prevent the soil from baking. 



Another consideration in the prairie States, and indeed 

 east to the Atlantic and south to the Gulf, is that no dis- 



