CULTIVATION OF ALFALFA 393 



is about two and one-half tons per acre, but on many farms an 

 average of three and one-half tons is made. Large yields of five to 

 six tons are not uncommon. 



The Seed Crop. The commercial seed crop of alfalfa is grown 

 principally in Utah, Kansas, Nebraska, California, and Arizona. It 

 is grown only in bright, sunshiny climates, and usually with a 

 low water supply. A large proportion of the seed is grown in 

 the irrigated districts, but water is usually withheld from the 

 seed crop. East of the Mississippi River alfalfa will usually 

 not produce a profitable seed crop oftener than once in three or 

 four years. 



The most favorable weather for securing a good seed crop is gen- 

 erally the hottest and driest portion of the summer. In the northern 

 States it is the general custom to leave the second crop for seed, while 

 from Kansas southward the third crop is left more often. An 

 ordinary yield of seed varies from three to six bushels per acre, while 

 eight to ten bushels is considered a very large yield. 



Growing Alfalfa in Rows. On the high, dry plains much 

 alfalfa is grown in cultivated rows. The rows are usually from two 

 to three feet apart. This method is considered practical only in 

 regions where the average rainfall is below fourteen or sixteen 

 inches. Very good seed crops can be secured in this way, and the 

 method is practised principally for seed growing on dry soil without 

 irrigation. 



Cultivation of Alfalfa. In most regions where alfalfa is 

 grown, as the stand begins to thin out, native grasses, and especially 

 blue-grass, begin to come in. To keep out these grasses, many 

 growers practise disking or harrowing their fields early in the spring 

 and after the first cutting. If the work is done with care and judg- 

 ment, it is possible to keep down the incoming grasses to a large 

 extent. 



It has also been thought for many years that the yield could be 

 increased by disking alfalfa sod, the theory being that the disk would 

 split up the old crown, causing a thicker stand. Experiments with 

 disking have usually shown an increased yield the first year or so 



