268 IRRIGATION PRACTICE 



when it comes after the plant has developed roots deeply 

 iii the soil. It is not an ideal dry-farm crop except where 

 the ground water is within reach, so that the roots may 

 draw water from below. It is essentially an irrigated crop, 

 and thrives best where the conditions of soil, tempera- 

 ture, relative humidity and sunshine are of an arid 

 character. 



There is nothing unusual in the preparation of land 

 for alfalfa. It requires a smooth surface preferably with 

 a slope of from 10 to 20 feet to the mile. It should be 

 sown in drill rows on land well stored with water. It is 

 difficult to obtain a stand on raw land. Oats may be sown 

 with it as a nurse crop. During the first two years of its 

 life it needs careful culture. By that time it is well estab- 

 lished and can then receive the regular treatment given 

 the matured alfalfa fields. Water should then be kept 

 off the land until it is actually needed, so that the plant 

 roots may be trained to strike deeply. 



166. Cultivation of alfalfa. Cultivation of alfalfa 

 fields to prevent the evaporation of water is very possible. 

 Each fall the alfalfa field is gone over with a disk or a 

 harrow, which loosens the top soil to prevent evaporation, 

 and, at the same time, leaves the soil so that it may easily 

 absorb water and be acted on by atmospheric agencies. 

 Meanwhile, the thoroughness with which the older plant 

 shades the ground tends greatly to diminish evaporation. 



It is a very common practice, after the last cutting, 

 to turn cattle and horses into the alfalfa field, to make use 

 of the late growth. When pastures are scarce, and hay 

 not abundant, this may be justifiable, but, considering 

 the effect upon the field, it is of doubtful value. The 

 tramping of the animals makes the soil hard and if there 

 are fall rains, the top soil may become puddled and thus 



