ALFALFA 337 



cutting and somewhat better than the third cutting. The 

 experiments were carried on two seasons with three lots 

 of 5 dairy cows each, each lot being fed for 4 weeks with 

 each cutting of hay after a preliminary feeding of 25 days. 

 The cows both years ate most of the third crop, followed 

 in order by the first and the second crops. The total 

 amounts of butter fat produced were, respectively, 707, 

 687 and 675 pounds for the first, second and third cuttings 

 in order. On the whole the experiment does not indi- 

 cate any marked difference in feeding value of the three 

 cuttings. 



400. Irrigation. A large proportion of the alfalfa 

 grown in the United States and Canada is produced under 

 irrigation in the semi-arid regions. The general practice 

 of growers is to use far more water than is necessary. This 

 is harmful, as in time it brings about a water-logged condi- 

 tion of the soil, which in itself is directly harmful to the 

 alfalfa, but indirectly far more so, as it causes soluble 

 alkali salts to rise and accumulate near the surface. On 

 this account it is best 'to apply only as much water as will 

 result in the production of satisfactory crops. This 

 amount varies principally according to the character of 

 the soil. To a less degree it is affected by the amount of 

 evaporation and transpiration, these increasing with high 

 temperature, dryness of the air and wind movements. 

 The optimum amount of water required needs, therefore, 

 to be determined in each locality by comparative plot 

 trials. 



401. Time to apply irrigating water. In irrigation 

 farming, alfalfa is practically always irrigated as soon as 

 each crop is removed from the field. Additional irrigations 

 are required in many places, the number depending on 

 both soil and climatic conditions. The best guide is to 



