“I can see no reason,” said the Doctor, “why you may not average 40 bushels of wheat per acre in a good season.” “The field of 14 acres,” said I, “where wheat followed wheat, yielded 23 bushels per acre. Last year it yielded 22 bushels per acre; and so we got in the two years 45 bushels per acre.” This field has had no manure of any kind for years. In fact, since the land was cleared, 40 or 50 years ago, I presume that all the manure that has been applied would not, in the aggregate, be equal to more than a good crop of clover-hay. The available plant-food required to produce these two crops of wheat came from the soil itself, and from the rain, dews, and atmosphere. The land is now seeded down with clover, and with the aid of a bushel or two of plaster per acre, next spring, it is not improbable that, if mown twice for hay next year, it will yield in the two crops three tons of hay per acre. Now, three tons of clover-hay contain about 33 lbs. of phosphoric acid, 90 lbs. of potash, and 150 lbs. of nitrogen. The last crop of wheat, of 22 bushels per acre, and say 1,500 lbs. of straw, would contain: In the grain. In the straw. In total crop. Phosphoric acid 11½ lbs. 3¾ lbs. 15¼ lbs. Potash 6¾ ” 9¾ ” 16½ ” Nitrogen 23 ” 9½ ” 32½ ” It seems very unkind in the wheat-plants not to give me more than 22 bushels per acre, when the clover-plants coming after will find phosphoric acid enough for 40 bushels of wheat, and potash and nitrogen enough for nearly 100 bushels of wheat per acre. And these are the three important constituents of plant-food. Why, then, did I get only 22 bushels of wheat per acre? I got 23 bushels on the same land the year previous, and it is not improbable that if I had sown the same land to wheat again this fall, I should get 12 or 15 bushels per acre again next year. But the clover will find plant-food enough for 40 bushels of wheat. “There is not much doubt,” said the Deacon, “that you will get a good crop of clover, if you will keep the sheep off of the land this fall. But I do not see what you mean by the clover-plants finding food enough for 40 bushels of wheat, while in point of fact, if you had sown the field again to wheat this fall, you would not, as you say, probably get more than 12 or 15 bushels of wheat.” “He means this,” said the Doctor. “If he had sown the land to wheat this fall, without manure, he would probably not get over 15 bushels of wheat per acre, and yet you both agree that the land will, in all probability, produce next year, if mown twice, three tons of clover-hay per acre, without any manure.