IRRIGATION 357 



highly important. The investment in the crop is so large 

 that the grower cannot always afford to depend upon 

 seasonal conditions for its success. Hence, irrigation in 

 humid regions often becomes necessary to protect a crop 

 against droughts. 



Water applied at the right time produces large yields of 

 high quality and earlier maturity. Seeds cannot germinate 

 without moisture, and transplanting often fails during hot, 

 dry weather. Irrigation promotes continuous growth and 

 development from the time the crop is seeded until maturity. 

 Greater benefits are also obtained from the fertilizers when 

 an abundant supply of moisture is at hand, as water is not 

 only a solvent for plant foods, but also serves as a medium 

 in their distribution. 



Various methods of irrigation are practiced by vegetable 

 growers. In the West, the furrow method is most generally 

 used. The land must be properly graded, however, for 

 carrying the water to the various parts of the garden by 

 this system. On porous soils or on land of uneven con- 

 tour, it is not desirable. 



Underground tile may be laid a foot to one and a 

 half feet in depth, in lines about ten to fifteen feet apart 

 throughout the field. This is a good system, as the crop 

 is watered from underneath and there is less loss by evapo- 

 ration. The foliage of the plants is not wet and there is 

 less liability of injury from fungous diseases. 



In the overhead system of irrigation overhead lines of 

 pipe about twenty-five feet apart are supported on posts 

 and run across the field. Openings about four feet apart 

 are made in this pipe, into which small nozzles are inserted. 

 These throw a fine mist over the crop. The advantages 

 of this system, which is popular with market gardeners, 



