KXPKKIMKNTS 0.\ WIILAT. 211 



(luces the largest yield of any plot in the lield. And well it niay, 

 for it has now Lad, in twelve years, 1G8 tons of barn-yard manure 

 per acre ! 



Several of the plots with aramonia-salts and mixed minerals, 

 are nearly up to it in grain, and ahead of it in straw. 



The ihirk^nth season (ISoo-fJ), gives llj bushels on the unnianur- 

 ed plot; over 3(JJ bushels on the plot manured with barn-3ard ma- 

 nure ; and over 40 Inishels on 8 /.dressed with GOO lbs. ammonia- 

 salts and mi.xed mineral manures. It will be notieed that 800 lbs. 

 ammonia-salts does not give quite as large a yield this year as GOO 

 lbs. I suppose 40 bushels per aere was all that the seison was capa- 

 ble of produiing, and an extra quantity of ammonia did no good. 

 400 lbs. of aramonia-salts, on 7(i, produced ;37i bushels per acre, 

 and 800 lbs. on IGA, only 37} biisljels. That extra half bushel 

 of wheat was produced at considerable cost. 



The fourteenth season (ls.")G-7), gives 20 bushels per acre on the 

 unmanured plot, and 41 bushels on the plot with barn-yard 

 manure. Mixed mineral manures alone on oa gives nearly 23 

 bushels per acre. Mixed mineral manures and 200 lbs. ammonia- 

 salts, on 0<i, give 35^ bushels. In otlier words the ammonia gives 

 us over 12 extra bushels of wheat, and 1,140 lbs. of straw. 

 Mineral manures and 400 lbs. ammonia-salts, on 7b, give 46i 

 bushels per acre. Mineral manures and 600 lbs. aramonia-salts, on 

 Sb, give nearly 49 bushels per acre. Mineral manures and 800 lbs. 

 of ammonia-salts, on 16ft, give 50 bushels per acre, and 4,703 lbs. 

 of straw. 



"This exceedingly heavy manuring," said the Deacon, "does 

 not pay. For instance, 



"200 lbs. ammonia-salts give an increase of 12i bushels per acre. 

 400 " " " " 2:;i 



6(X) " " " " 26 " " 



800 " " " " 27 " " 



The Deacon is right, and Mr. Lawes and Dr. Gilbert call especial 

 aitention to this point. The 200 lbs. of ammonia-salts contain 

 about 50 lbs. of ammonia, and the 400 lbs., 100 lbs. of ammonia. 

 And as I have said, 100 lbs. of ammonia per acre is an unu.sually 

 heavy dressing. It is as much ammonia as is contained in 1,000 

 lbs. of average Peruvian guano. We will recur to this subject. 



The ffleenth season (1857-8,) gives a yield of 18 bushels of wheat 

 per acre on the continuously unmanured plot, and nearly 39 

 bushels on the plot continuously manured with 14 tons of barn- 

 yard manure. Mixed mineral manures on 5a and 56, give a mean 

 yield of less thau 19 bushels per acre. 



