Increase of Potato Crop by Irrigation 173 



The Rural New-Yorker has been the chief variety grown, but 

 each year an unnamed variety of the Burbank type has been used 

 to finish out the piece. 



The potatoes were planted about the middle of May each year, 



Fig. 26. 



Difference in yield between Rural New-Yorker potatoes, 

 irrigated and not irrigated, in 189G. 





Fig. 27. Difference in yield between potatoes of Burbank type irrigated 

 and not irrigated, in 1896. 



Fig. 28. Difference in yield between Rural New-Yorker potatoes, 

 irrigated and not irrigated, in 1897. 



and given flat cultivation after every rain, or oftener, until the 

 vines were so large as nearly to cover the ground, when they were 

 hilled with a double shovel plow drawn through the center of each 

 row, forming ridges about 5 inches high, the nose of the shovel 

 passing about 3 inches below the surface of the ground. 



