MANLRES F(»K TOTATOES. 263 



Biushcls ])er acre. 



I 6i c wt. superphosphate | 



l.-|2i " inuiiale of potash >-321 



("21 " 8iilpbalf of armuoiiia ) 



o i tii cwt. 8iipirpliot;i)bute (^ .,tjg 



"(24 " t<ulphatc of ammonia )~ 



3. No iiianurt- 252 



- 3 6i ewt. suiterphosphatc * ... , 



*■ ) 2i •• muriate of pctasb ) 



5. 2i cwt. fuliiliale ot auimuiiia 238 



6. Lj tons farm-} aid manure 3t>5 



" It is curious," said the Doctor, " that tiic plot with sulphate of 

 ammonia alone sliould produce less than the no-manure plot." 



"The sulphate of anunonia," said I, "may have injured the 

 seed, or it may have produced too luxuriant a growth of vine." 



Another series of experiments was m.ide on another portion of 

 the sjime field in 1871. The "no-manure" plot produced 337 

 bushels per acre. Manures of various kinds were used, hut the 

 largest yield, 351 iiushels per acre, was from superpliosphate and 

 sulphate of ammonia; fourteen tons barn-yard manure prod; ce 

 340 bushels per acre; and Mr. Iluntir remarks: "It is evident 

 that, when the produce of the unmanured soil n^aches nine tons 

 [336 bushels] per acre, there is but little scope for manure of any 

 kind." 



" I do not sec," .<5aid the Doctor, " that you have answered my 

 question, but I suppose that, with potatoes at fifty cents a bushel, 

 and wheat at $1.50 per bushel, artificial manures can be more 

 profitably used on potatoes than on wheat, and the same is prob- 

 ably true of oats, barley, corn, etc." 



I have long been of the opinion that artificial manures cnn be 

 applied to potatoes with more profit than to any other ordinary 

 farm-crop, for the simple rea.son that, in this country, potatoes, on 

 the average, command relatively high prices. 



For instance, if average land, without manure, will produce fif- 

 teen bushels of wheat per acre and 100 bushels of potatoes, and a 

 given quantity of manure costing, say if>'2~), w ill double the crop, 

 we have, in the one case, an inrreasc of: — 



15 bushels of wheat at 11.50 $22.50 



15 cwt. of straw 3. .50 



?2fi.OO 



Cost of manure 25.00 



Profit from ueing manure f 1.00 



A.nd in the other: — 



100 bushels of potatoes at 50 cents ^.W.OO 



Cost of manure .. 25.00 



Profit from using manure :f25.00 



