Field Experiments in Manuring, 1903-4. 



689 



Fine, is the portion wliicli passes through a sieve of 50 linear 

 meshes to the inch, and coarse, the portion retained on the 50 inch 

 mesh sieve. It is advisable for a quick operative manurial effect to 

 have a much lartjer percentMge of fine material than even shown in 

 this sample, and, in purchasing, the farmer should observe this point 

 as well as noting the contents of pliosphoric acid and nitrogen, which, 

 in a good sample, should approximate to or might exceed the figures 

 given above. 



The Cost of the Three Manures. 



The cost of the three manures is another point requiring con- 

 sideration by the farmer, for although one of the manures might give 

 a loAver return in the field than a corresponding quantity of another, 

 it might be still advisable to purchase this manure giving the lower 

 result on account of its lower price. For instance, taking the average 

 figures just dealt with, 2 cwt of bonedust of the composition of the 

 one above would give "13 tons more hay than an equal quantity 

 of Thomas phosphate, or 1 ton of bonedust would give a larger 

 increased yield of hay by 1 "8 tons than 1 ton of Thomas phosphate. 

 But Thomas phosphate is quoted at £4 10s. a ton, while a bonedust 

 of the above composition would probably cost £5 lOs. or more per 

 ton. If the value of the increased yield produced by one manure 

 did not equal or exceed the extra cost of that manure, it would 

 clearly be of no benefit to give that manure the preference. In the 

 present case it does, although, with the former higher standard of 

 quality possessed by Thomas phosphate and in seasons not so excepr 

 tionally favorable to the action of bonedust as the last appeared to be, 

 it is probable that with present prices obtaining the difference would 

 not be very considerable. For the relative positions in the experi- 

 ments (Table B) held by the three manures based on money profits, 

 the following figures might interest the farmer : — 



These figures bring into very striking prominence the superiority 

 of the superphosphate as a phosphatic manure. The farmer, however, 

 will clearly understand that it is only from an article showing a 

 similar chemical composition to the one used in these experiments 

 that he can expect corresponding results. There are different 

 qualities or grades of artificial fertilizers as there are different 

 qualities of tea, sugar and other articles of commerce. The farmer 

 should not merely go upon the name of a manure, but his practice 



