72 THE BOOK OF ALFALFA 



as the plants from the previous sowing came up so thick 

 as to choke out those from the later seeding. In some 

 states a common plan of thickening a stand is to let the 

 third crop ripen seed, and then about the last of Septem- 

 ber disk and harrow the seed into the ground where it 

 grew. This frequently saves the stand and adds many- 

 years to its life. But where a field begins to fail after a 

 third year it is usually better to plow it up and raise one 

 or two crops of corn, a crop of oats or of millet, and 

 then reseed. 



ALFALFA UNDER IRRIGATION 



The greatest yields of alfalfa are produced by irriga- 

 tion. Reported yields of six or more cuttings, aggregat- 

 ing eight to twelve tons per acre each year, are almost 

 invariably, yet not always, from districts where irrigation 

 is practiced. It is claimed by experiment station experts 

 from the irrigation states that the tendency is to use too 

 much water; too much at a time and too often. The 

 general recommendation is to irrigate thoroughly before 

 the ground is plowed or disked, and not again till 

 the alfalfa is about four inches high. Then again a week 

 before each cutting. It has been found that old alfalfa 

 fields do not need as much water as new fields, the alfalfa 

 roots seeming to find moisture and bring it to the surface. 



It is insisted that the surface must be perfectly 

 smooth to keep water from settling into low places and 

 smothering the plants. Some farmers do not irrigate for 

 the second crop if as much as two inches of rain falls 

 after the first mowing. Others claim that old fields do 

 not need flooding for the second crop even if there has 

 been no rainfall after the first cutting. 



