80 Strawberry-Growing 



IRRIGATION IN HUMID REGIONS 



The distinction between humid, semi-arid and arid 

 regions is wholly arbitrary. A region having an annual 

 rainfall of twenty inches or more is generally regarded 

 as humid, provided this is well distributed throughout 

 the year; if so, all ordinary farm crops can be grown. 

 Usually, however, the rainfall is not well distributed ; 

 some months may be practically rainless. Under these 

 conditions, supplemental irrigation may be profitable as 

 an insurance against drought. The Hood River Valley, 

 with an annual rainfall of thirty inches, illustrates the 

 value of supplemental irrigation in a humid region. The 

 summers of the Atlantic states, where commercial straw- 

 berry-growing is highly developed in connection with 

 trucking, frequently are marked by protracted droughts. 

 These may be so severe that most of the leaves die and 

 the plants become practically dormant. When rains 

 come the plants revive, produce a second crop of blossoms, 

 and a fall crop is harvested. 



Irrigation experiments in humid regions. 



Experiments have yielded conflicting results, as might 

 be expected in view of the unstable factors involved. 

 In Wisconsin, marked benefit was secured from irri- 

 gation in 1894 and 1895.^ In Missouri, the yield was 

 increased six times in dry seasons. The test of irrigation, 

 however, is not how much it will benefit the crop in a 

 single dry year, but whether it will pay over a series of 

 years. In 1901 the New Jersey Experiment Station 

 concluded : " Combining the results of four seasons, irri- 

 gation has given a small increase in early yield only. 



1 Kept. Wis. Exp. Sta., 1894, pp. 332-7. 



