240 TALKS OX MANURES. 



The produce of barley the first season (1852), was, per acre : 



On the unmanured plot 27i bushels 



With superphosphate of lime 2SI 



potash, soda, and magnesia i?6f 



" and superphosphate 32* 



14 tons barn-yard manure 33 



200 Ibs. ammonia-salts alone 36f 



and superphosphate 381 



and potash, soda, and magnesia 36 

 and superphosphate, potash, 



soda, and magnesia 401 



" 400 Ibs. ammonia-salts alone 44i 



The 200 Ibs. of ammonia-salts contain 50 Ibs. of ammonia=41 

 Ibs. nitrogen. 



It will be seen that this 50 Ibs. of ammonia alone, on plot la, 

 gives an increase of nearly 10 bushels per acre, or to be more accu- 

 rate, it gives an increase over the unmanured plot of 503 Ibs. of 

 grain, and 320 Ibs. of straw , while double the quantity of ammonia 

 on plot la.a., gives an increase of 17 bushels per acre or an in- 

 crease of 901 Ibs. of grain, and 1,144 Ibs. of straw. 



"Put that fact in separate lines, side by side," said the Deacon, 

 " so that we can see it." 



Total 

 Grain Straw Produce. 



50 Ibs. of ammonia gives an increase of 503 Ibs. 704 Ibs. 1207 Ibs. 



100 " " " " " " " ....901 " 1144 " 2045 " 

 The first 50 Ibs. of ammonia gives an in- 

 crease of 503 " 704 " 1207 " 



The second 50 Ibs. of ammonia gives an in- 

 crease of COS " 540 " 738 " 



" That shows," said the Deacon, " that a dressing of 50 Ibs. per 

 acre pays better than a dressing of 100 Ibs. per acre. I wish Mr. 

 Lawes had sown 75 Ibs. on one plot." 



I wish so, too, but it is quite probable that in our climate, 50 

 Ibs. of available ammonia per acre is all that it will usually be 

 profitable to apply per acre to the barley crop. It is equal to a 

 dressing of 500 Ibs. guaranteed Peruvian guano, or 275 lb&. nitrate 

 of soda. " Or to how much manure ? " asked the Deacon. 



To about 5 tons of average stable-manure, or say three tons of 

 good, well-rotted manure from grain-fed animals. 



" And yet," said the Deacon, " Mr. Lawcs put on 14 tons of yard 

 manure per acre, and the yield of barley was not as much as from 

 the 50 Ibs. of ammonia alone. How do you account for that?" 



Simply because the ammonia in the manure is not ammonia. It 

 is what the chemists used to call " potential ammonia." A good 

 deal of it is in the form of undigested straw and bay. The nitro- 

 genous matter of the food which bas been digested by the animal 



