ARID AGRICULTURE. 95 



from man. Many native, or wild, hay mead- 

 ows are irrigated in this way with little super- 

 vision other than turning on the water in the 

 Spring and turning it off again a week or so be- 

 fore harvest time. The consequence is usually 



Plate XIV. Rock River, with Irrigated Meadows. 



Photo by Stimson. 



that the meadow is continually under water to a 

 varying depth during the growing season. Only 

 the Avater-loviiig or swamp grasses, and the 

 rushes and sedges, survive such treatment. The 

 finer native grasses, as the wheat grasses, are 

 rapidly killed out. As the coarse grasses thrive, 

 and give comparatively good yields, the practice 



