592 Thirty-second Annual Report 



vals of two weeks throughout the summer with scion wood held 

 in a dormant state and with fresh wood when it becomes avail- 

 able. In addition to the work done at the University, a num- 

 ber of grafts have been made on native walnut trees in differ- 

 ent parts of the State, particularly at Prescott and in several 

 of the wooded canyons in the Santa Rita, Chiricahua, and Santa 

 Catalina mountains. 



IRISH POTATOES 



The most conspicuous work with Irish potatoes comprises 

 a comparative test of the ridge and the level methods of cul- 

 ture conducted at the Yuma Station. The main point of differ- 

 ence between these two methods lies in the fact that with the 

 former the seed potatoes were planted on rather high ridges 

 which prevented the irrigation water from coming in direct 

 contact with the tubers of the plants. In the level method of 

 culture the tubers formed on the level with or a little below 

 the irrigation water line. 



The results of the test are summarized in Table VI. 



TABLE VL — COMPARISON OF THE RIDGED AND THE LEVEL METHODS OF 

 CULTURE FOR IRISH POTATOES 



RIDGE METHOD 



Date of Yield Percent 



Variety harves t acre basis culls 



Peach Blow May 16 7602~lbs. 25 



White Rose May 16 1504 " 12 



Early Rose May 10 2457 " 48 



LEVEL METHOD 



~ Date of Yield Percent 



Variet y harve st acr e basi s culls 



Peach Blow May 25 590fTbs^ ~ 25~ 



White Rose May 25 1428 " 15 



Early Rose May 17 3730 " 30 



It will be noted that the Peach Blow variety yielded 1701 

 pounds and the White Rose 75 pounds more per acre under the 

 ridge method of culture, while the Early Rose produced 1273 

 pounds less. However, the most important fact brought out 

 by the experiment, which holds true for all varieties used, is 

 that with the ridge method the crop matured earlier. This is a 

 valuable factor as viewed from the standpoint of marketing. In 

 the case of the Peach Blow and White Rose a difference of nine 

 days and in the case of the Early Rose a difference of seven 

 days in favor of the ridge method is shown. 



