Irrigation in Humid Regions 107 



crops as fruit, grain, alfalfa, clover, and the like, the sur- 

 face system is employed, and furnishes the best practi- 

 cable method of applying the water. 



The overhead system is employed in the humid as well 

 as the arid sections of the country, particularly in the 

 case of those areas intensively cultivated. It has been 

 used mostly on such crops as cucumber, strawberry, 

 lettuce, tomato, bean, eggplant, potato, squash, and 

 the like — in fact all garden crops. The plan is to lay 

 stationary pipes over the whole field, or to provide movable 

 sections of pipes mounted on wheels. The advantages of 

 this system are: (1) The crops are sprayed naturally when- 

 ever desired; (2) there is no waste land; (3) water is applied 

 uniformly over the entire surface; (4) it is especially 

 adapted to the shallow-rooted crops. The disadvantages, 

 on the other hand, are: (1) It necessitates an expensive 

 system of piping; (2) it requires a powerful pumping plant 

 which gives a pressure of twenty to fifty pounds to the 

 square inch ; (3) the quantity of water wasted by evaporation 

 is excessive; (4) the pipes interfere with tillage operations. 



The so-called Skinner system of irrigation- may be 

 cited as an example of the overhead method. It consists 

 essentially of pipes supported above the ground 40 to 60 

 feet apart, in which are set small nozzles at intervals of 3 

 or 4 feet. The pipe is turned by means of a union and 

 handle to cover ground very near or more distant from the 

 line. The best water-pressure is thirty to forty pounds, 

 and a single line throws its rain-like spray about 25 feet. 

 In addition to the advantages mentioned above, advocates 

 of this system assert that it is a protection against frost, 

 and an excellent means of distributing insecticides, fungi- 

 cides and commercial fertilizers. 



To what extent irrigation will increase in the East 



