IRRIGATION OF ALFALFA. 



HOW MUCH WATER GIVES BEST RESULTS. 



By GUY E. MITCHELL. 



"Alfalfa as a Hay Crop'' is the title of a bulletin prepared by 

 Prof. B. C. Buffum, the agriculturist of the Wyoming Experiment 

 Station, and his treatment of the subject is of more than passing in- 

 terest to farmers of the great arid region, where no other plant is held 

 in such high esteem by those who have had the largest experience in 

 irrigation farming. 



"Although alfalfa Is extremely hardy," says Prof. Buffum, "and 

 will live through long periods of drouth it will not produce hay unless 

 irrigated. It is of vital importance to apply water at the right time, 

 and conduct the irrigation in the right way. Flooding as the native 

 meadows are flooded for long periods of time, is much more quickly 

 fatal to alfalfa than it is to our best native grasses. 



"It will not do to turn the water on and look at it once a week to 

 see that it is still running. Alfalfa soon dies if its feet are kept wet, 

 and it needs long breathing spells and warm growing weather. 

 Where the irrigating water is cold it produces a chilling effect, and 

 the irrigation should be done quickly and the water turned off as soon 

 as the ground has become thoroughly wet. The best time to irrigate 

 alfalfa is immediately after the hay has been removed. Some irrigate 

 just before the hay is cut, but our observations indicate that much 

 better results are obtained by irrigating after cutting. If the weather 

 is very dry, light irrigations may be needed between the cuttings. 

 We believe in irrigating in the fall, some time after the last cutting 

 has been made, to keep the soil from becoming too dry during the 

 winter. It should not be done so late, however, that the ground is 

 apt to freeze hard while very wet, as this seems to be the principal 

 cause of winter killing. 



"Too much water is fatal either in the summer or winter. On the 

 Wyoming Experiment Farm one season we irrigated one-half of a field 

 of alfalfa as late as October, leaving the other half without water. 

 The part irrigated started earlier the next spring and up to the time 

 of the first cutting the dividing line between that which had not been 

 irrigated and that which was watered late in the fall was distinctly 

 visible, as the hay grew two or three inches higher on the fall irri- 

 gated portion. 



"By duty of water we mean the amount which is used on the land 

 Alfalfa is a perennial plant which occupies the land all the time. Its 



