1917] Forbes: Irrigation Effects of Copper Compounds Upon Crops 475 



Observations were made June 23, 1905, on the second cutting, 

 just beginning to bloom, the field having been irrigated twice 

 since the last cutting. After stirring and raking, the yield of 

 dry hay was weighed June 24. Weather very hot and dry. Fol- 

 low^ing are the data relating to this series : 



* Corrected for thin stand and trash. 



2. Alfalfa slightly affected hy tailings, June 13, 1916. 



The same three lands, continuously in alfalfa since 1905. A 

 perfect stand, thin spots reseeded by means of a seed crop in 

 1915. The field had been spring-tooth harrowed each winter for 

 about ten years, especially at heads of lands, to break up the 

 tailings blanket and secure better penetration of irrigating water. 



As in 1905, ten feet next the ditch was discarded, also the 

 extreme lower portion of the field. Johnson grass had nearly 

 entirely disappeared. 



Observations were made June 13, 1916, on the second cutting, 

 just beginning to bloom, the field having been irrigated twice 

 since the last cutting. After raking and piling, the dry hay 

 was hauled and weighed June 17. The weather was moderately 

 hot and dry; and conditions generally the same as those under 

 which the crop was cut in 1905. Following are the data for the 

 second series of observations: 



