9 Sept., 1907.] 



Potato Ex-perimental Fields. 



557 



in yield, except in the case of the lona field where the soil was a deep 

 peat. Tlije effect of lime and farm manure, particularly the former has 

 been disappointing, but there are indications that both of these amendments 

 must be accompanied by artificial manures. 



The next group of fields differs only from the preceding in the substitu- 

 tion of sulphate of ammonia for nitrate of soda and the elimination of the 

 farm manure dressing. 



Manures used. 



\. 2 cwt. Superphosphate. B. 2 cwt. Superphosphate, 1 cwt. Sulphate of Ammonia. C. No 

 manure. D. Same as B, and 1 cwt. Potash Sulphate. E. 4 cwt. Lime. 



The returns from this group of fields do not show any striking dif- 

 feiences for various manure dressings, but they strongly emphasize the 

 value of manuring by the production of an extra ton of potatoes per acre 

 over ground not manured : — ■ 



A. B. C. 



D. 



3-5 



E. 



Tons per acre ... 3.8 ... 3.4 ... 2.6 



The third group of fields comprises rich volcanic soils. The manure 

 dressings are identical with the preceding group, but the lime is replaced 

 by farm manure in section E. 



The average yields for the different sections do not show considerable 

 varietv. 



A. B. C. D. E. 



6.1 



Tons per acre 



5-5 



5-0 



5-3 



Wliile it is not surprising to find a yield of 5 tons per acre from un- 

 manured ground, it is gratifying to find that even on these rich soils, 

 manures rationally applied can still increase the yield by over one ton per 

 acre, as on section D. The effect of the stable manure has also brought 



