I907-] 



Problems in Potato Growing. 



67 



proved by a sufficient number of precise experiments, the 

 point under notice cannot be regarded as clearly settled. 



Varieties. — The results of experiments with different varieties 

 of potatoes differ greatly with localities, so that they arc of little 

 more than local value. Taking a great number into account, it 

 may be said that no first-early variety stands out prominently as 

 the best yielder. Among second earlies, however, British Queen 

 still occupies a position in reference to yield and quality com- 

 bined which is second to that of no other variety of its class ; 

 while Up-to-Date in this double connection has not yet been 

 clearly deposed from its premier place, although it lias been 

 beaten in yield alone in some recent trials by some closely allied 

 variel ies such as Factor and Duchess of Cornwall, or both. 



M a n uring. — With respect to manuring, there is a vast accumu- 

 lation of evidence in support of certain conclusions, as follows : 

 That nearly a maximum crop can be grown with the use of about 

 20 tons of farmyard manure, and that the addition of artificial 

 fertilizers to this heavy dressing, although it may increase the 

 \ u ld, hardly ever increases it sufficiently to prove remunerative ; 

 that at least as good a crop as a rule can be obtained by the use 

 of half the large dressing of farmyard manure and a complete 

 mixture of artificials containing nitrogen, phosphoric acid and 

 potash, as by the application of the full quantity of the natural 

 manure alone, and at less expense ; that the omission of any one 

 of the three classes of artificial manure almost invariably leads 

 to a reduction in the yield of potatoes ; that no quantities of 

 artificials yet tried have proved of equal efficiency to the com- 

 bination of natural and artificial manures, although the profit 

 from the application of artificials alone has sometimes been the 

 greater. 



A considerable number of trials have indicated that the 

 quality of potatoes grown with artificial manures alone is 

 superioi to that of potatoes thrown with the help of fannvard 

 manure, and this may be regarded as the rule, to which varying 

 circumstances afford exceptions. 



Spraying. -It lias been fully established that spraying with 

 Bordeaux Mixture, particularly when done two or three times in 

 a season, reduces the percentage of disease as a nil* 1 w hen there is 

 any. It is also common] v believed to increase the yield by pro- 

 longing the life of the haulm, at least, so far as the main crop of 



