On the plot dressed with 14 tons of farmyard-manure and 200 lbs. ammonia-salts, the average yield of hay for 8 years was 5,544 lbs. per acre. After the eighth year the farmyard-manure was discontinued, and during the next twelve years the yield of hay averaged 3,683 lbs., or 1,149 lbs. more than the continuously unmanured plot.
In 1859, superphosphate of lime was used alone on plot 3, and has been continued ever since. It seems clear that this land, which had been in pasture or meadow for a hundred years or more, was not deficient in phosphates.
“It does not seem,” said the Deacon, “to have been deficient in anything. The twentieth crop, on the continuously unmanured plot was nearly 1¼ ton per acre, the first cutting, and nearly ¾-ton the second cutting. And apparently the land was just as rich in 1875, as it was in 1856, and yet over 25 tons of hay had been cut and removed from the land, without any manure being returned. And yet we are told that hay is a very exhausting crop.”
“Superphosphate alone,” said the Doctor, “did very little to increase the yield of hay, but superphosphate and ammonia produced the first year, 1859, over a ton more hay per acre than the superphosphate alone, and when potash is added to the manure, the yield is still further increased.”
“Answer me one question,” said the Deacon, “and let us leave the subject. In the light of these and other experiments, what do you consider the cheapest and best manure to apply to a permanent meadow or pasture?”
“Rich, well-decomposed farmyard or stable manure,” said I, “and if it is not rich, apply 200 lbs. of nitrate of soda per acre, in addition. This will make it rich. Poor manure, made from straw, corn-stalks, hay, etc., is poor in nitrogen, and comparatively rich in potash. The nitrate of soda will supply the deficiency of nitrogen. On the sea-shore fish-scrap is a cheaper source of nitrogen, and may be used instead of the nitrate of soda.”