74 THE BOOK OF ALFALFA 



irrigate late in the fall and apply a top-dressing of light 

 barnyard manure, which is found to be of great service 

 in several ways/' 



INFLUENCE OF IRRIGATION UPON COMPOSITION. 



I find no report of experiments published by any sta- 

 tion in which the influence of irrigation upon alfalfa hay 

 is made a special study, but Bulletin No. 80 of the Utah 

 station contains a great deal of information along this 

 line relative to grain crops, potatoes, and mixed grasses. 

 In summing up the results of the experiments, the fol- 

 lowing conclusions are given : 



"Heavy irrigations increase the percentage of weight 

 of the heads of plants ; li^ht irrigations increase the rela- 

 tive weight of leaves. 



"Irrigation modifies definitely the composition of 

 plants and plant parts ; the seeds are affected more than 

 any other plant part 



"The percentage of protein in corn kernels was 

 increased from 12.05 to 15.08, as the amount of irriga- 

 tion decreased; in oat kernels from 14.07 to 2079; in 

 wheat kernels from 15.26 to 26.72. In all these seeds 

 the fat and nitrogen-free extracts were increased by lib- 

 eral waterings. 



"Increased irrigations increased the starch content 

 and decreased the protein content of potatoes. 



"The water in plants is somewhat dependent on the 

 water in the soil. 



"The proportion of ear corn to stover increased regu- 

 larly with the increased application of water. 



"The percentage of grain in the wheat crop increased 

 with increased irrigations. 



