Suppose a young man has a farm of 100 acres, devoted principally to dairying. Some of the land lies on a creek or river, while other portions are higher and drier. In the spring of the year, a stream of water runs through a part of the farm from the adjoining hills down to the creek or river. The farm now supports ten head of cows, three horses, half a dozen sheep, and a few pigs. The land is worth $75 per acre, but does not pay the interest on half that sum. It is getting worse instead of better. Weeds are multiplying, and the more valuable grasses are dying out. What is to be done? In the first place, let it be distinctly understood that the land is _not_ exhausted. As I have before said, the productiveness of a farm does not depend so much on the absolute amount of plant-food which the soil contains, as on the amount of plant-food which is immediately available for the use of the plants. An acre of land that produces half a ton of hay, may contain as much plant-food as an acre that produces three tons of hay. In the one case the plant-food is locked up in such a form that the crops cannot absorb it, while in the other it is in an available condition. I have no doubt there are fields on the farm I am alluding to, that contain 3,000 lbs. of nitrogen, and an equal amount of phosphoric acid, per acre, in the first six inches of the surface soil. This is as much nitrogen as is contained in 100 tons of meadow-hay, and more phosphoric acid than is contained in 350 tons of meadow-hay. These are the two ingredients on which the fertility of our farms mainly depend. And yet there are soils containing this quantity of plant-food that do not produce more than half a ton of hay per acre.