The 200 lbs. of ammonia-salts contain 50 lbs. of ammonia = 41 lbs. nitrogen. It will be seen that this 50 lbs. of ammonia alone, on plot 1_a_, gives an increase of nearly 10 bushels per acre, or to be more accurate, it gives an increase over the unmanured plot of 503 lbs. of grain, and 329 lbs. of straw, while double the quantity of ammonia on plot 1_a.a._, gives an increase of 17¼ bushels per acre--or an increase of 901 lbs. of grain, and 1,144 lbs. 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 lbs. of ammonia gives an increase of 503 lbs. 704 lbs. 1207 lbs. 100 ” ” ” ” ” ” ” 901 ” 1144 ” 2045 ” The first 50 lbs. of ammonia gives an increase of 503 ” 704 ” 1207 ” The second 50 lbs. of ammonia gives an increase of 398 ” 540 ” 738 ” “That shows,” said the Deacon, “that a dressing of 50 lbs. per acre pays better than a dressing of 100 lbs. per acre. I wish Mr. Lawes had sown 75 lbs. on one plot.” I wish so, too, but it is quite probable that in our climate, 50 lbs. 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 lbs. guaranteed Peruvian guano, or 275 lbs. 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. Lawes put on 14 tons of yard manure per acre, and the yield of barley was not as much as from the 50 lbs. 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 hay. The nitrogenous matter of the food which has been digested by the animal and thrown off in the liquid excrements, is in such a form that it will readily ferment and produce ammonia, while the nitrogenous matter in the undigested food and in the straw used for bedding, decomposes slowly even under the most favorable conditions; and if buried while fresh in a clay soil, it probably would not all decompose in many years. But we will not discuss this at present. “The superphosphate does not seem to have done much good,” said the Deacon; “3½ cwt. per acre gives an increase of less than two bushels per acre. And I suppose it was _good_ superphosphate.”