LEGUMINOUS FORAGE CROPS 187 



210. After Treatment. For its best growth the young alfalfa 

 plant requires an abundance of soluble nitrogen in the soil. 

 If it has not been applied by means of stable manure, and even 

 if stable manure has been used, 100 pounds of nitrate of soda 

 may be sown two to three weeks after alfalfa has been seeded, 

 if the alfalfa lacks at this time a deep green color. If sown 

 without grain or nurse crop, it should be clipped well above 

 the crown in the latter part of June or early in July in order 

 to retard the growth of weeds and cause the alfalfa to produce 

 a larger number of stems and thus shade the ground more 

 fully. Doubtless, also, this procedure helps in humid climates 

 to check the leaf-spot. (218) Subsequent clippings will 

 depend upon the growth of alfalfa and weeds, but usually an- 

 other should be given sometime in August. When a nurse 

 crop is used, the cutting of this answers for one of the clip- 

 pings. (216) Old meadows are sometimes worked with 

 a disk harrow. It is claimed that this method splits the crown 

 and thus increases the number of independent plants, and 

 thereby increases the yield. Old meadows also respond to the 

 application of stable manure spread upon the land, preferably 

 with a manure spreader immediately after the last crop. 



211. Irrigation. The soil may be irrigated before seeding, 

 but after the plants have started the land should not be ir- 

 rigated the first season, because the soft mud may cover the 

 small plants and kill them. Usually irrigation is not necessary 

 to grow the first cutting. For the second cutting, the land may 

 be irrigated immediately after the first crop is harvested, or 

 about one week before it is harvested, which is believed to give 

 the best results. The Utah Station has shown that less water 

 is required to grow fair crops when applied at intervals of 

 three to four weeks. The Wyoming Station applied 2.22 acre- 

 feet of water during the season to alfalfa when the rainfall 

 was about 1.5 inches. The Colorado Station recommends 20 to 



