IRRIGATION OF FIELD CROPS. 245 



is anywhere from fifteen to twenty tons to the acre, 

 and the crop is gathered with a potato digger. 



Meadows. — Grasses may be irrigated at almost 

 any time during the season. The best native hay 

 grasses, the blue stems, poas, timothy, fescues, grama, 

 etc., produce stems just underneath or at the surface 

 of the ground. Wherever these underground stems or 

 rootstalks are broken, other stems and leaves will 

 grow. If these grasses are not thick enough, a 

 thorough harrowing in the spring before the water is 

 turned on answers the double purpose of breaking up 

 the rootstalks, causing the sod to thicken, increasing 

 the yield and leaving the ground in the best condition 

 for absorbing water. Native meadows should be sup- 

 plied with comparatively large amounts of water in the 

 spring before the stalks begin to shoot, if the rainfall 

 has been insufficient. No water should be given any 

 hay crop for some length of time before it is to be cut. 

 This allows the plant to store up larger amounts of 

 nutrition, and the ground is firm and in good condition 

 for cutting and curing the hay. Alfalfa and other 

 clovers, where more than one crop is to be harvested 

 in the season, .should be quickly and thoroughly irri- 

 gated soon after the previous crop has been removed. 

 One irrigation is usually sufficient for each crop. The 

 same treatment should be given native meadows which 

 are to be used for pasture. The stubble is easy to 

 irrigate, and in this condition the plants need moisture 

 to enable them to put forth a new growth. 



In England meadow irrigation is quite commonly 

 pra(5liced. In many places a tide of rainwater is 

 turned into stockyards having descending surfaces, the 



