AVERAGE YIELD ()!• I'OTATols ij:; 



Abundance," five years; "Bruce," one yaw; and "Wliii.- 

 Beauty of Hebron," 1807-1001. Tlie question was not as to 

 the comparative merits of different varieties, l)ut different 

 sorts were selected on the supposition tliat in irrowiii^ tlir crop 

 year after year, a change was desiral)le, especially witli a view- 

 to the avoidance or lessening of disease. The special object 

 was to ascertain the manurial re(]uireinents of the cro[) and 

 the comparative character and composition of the produce. 

 Table XLY. gives the details of the manuring and the 

 average produce for the whole period of twenty-six years. 



Table XLV. — Potatoes, overage yield ^Kr acre over 26 yenrs 

 (1876-1901). 



* Applied in the first 6 years only (1870-81). 



t 3-5 cwt. Superphosphate also in the first 7 years (1876-82] 



t 550 lb. Nitrate of Soda also in the first years (1876-81). 



The crop was grown continuously without manure, with 

 various artificial manures, and also with farmyard manure, both 

 alone and with some artificial manures. There were ten 

 differently manured plots, and under each of the ten conditions 

 the crop more or less declined over the later compared with the 

 earher years. The average produce per acre of total tubers 

 over the twenty-six years w\a.s — without manure, only l'7 4 

 cwt; with ammonium-salts alone, 34-0 cwt.; with nitrate of 

 soda alone, 42-5 cwt. ; with superphosphate alone, r)4-4 cwt. ; 



