it may be said, speaking very generally, that the equivalent of about one per cent. of the total phosphorus contained in the plowed soil does become available for the crops under average conditions.  On this basis one hundred and sixty pounds of phosphorus would furnish about one and one-half pounds for the crops during one season.  But in such a soil the phosphorus still remaining may be the most difficultly soluble, and the supply of decaying organic matter may be extremely low, so that possibly less than one pound per acre would become available, and this would meet the needs of less than four hundred pounds per acre of clover hay.  Furthermore, the supply grows less and less with every crop removed.

“With your ordinary soil, carrying twelve hundred and seventy pounds of phosphorus, perhaps you may be able by a liberal use of decaying organic matter to liberate ten or fifteen pounds of phosphorus, or sufficient for a crop of forty to sixty bushels of corn; and, with a subsoil richer in phosphorus than the surface, and with more or less of the partially depleted surface removed by erosion year by year, the supply of phosphorus is thus permanently provided for unless the bed rock is brought too near the surface.  It is doubtful if the direct addition of phosphorus to your sloping lands will ever be necessary or profitable.  Certainly such addition is not advisable until you have brought the land to as high a state of fertility as is practicable by means of limestone, legumes, and manure.”

“That seems clearly to be the case with most of the land now under cultivation on this farm,” said Mr. West “Can you tell me anything about this hydrated lime?

“I can tell you it is correctly named,” Percy replied. “Hydrated means watered, and an investment in hydrated lime is properly classed with other watered investments.  If you prefer to use hydrated lime I would suggest that you buy fresh burned lump lime and do the hydrating yourself, which only requires that you add eighteen pounds of water to each fifty-six pounds of quick lime; in other words, that you slack the lime by adding water in the proper proportion.  Both quick lime and hydrated lime are known as caustic lime.  Webster says that the word caustic means ’capable of destroying the texture of anything or eating away its substance by chemical action.’

“This definition is correct for caustic lime, as you can easily determine by keeping your hand in a bucket of slacked lime a few minutes.  Caustic lime eats away the organic matter of the soil.  In an experiment conducted by the Pennsylvania Experiment Station, during a period of sixteen years, eight tons of hydrated lime destroyed organic matter equivalent to thirty-seven tons of farm manure, as compared with the use of equivalent applications of ground limestone; and, as an average of the sixteen years, every ton of caustic lime applied liberated seven dollars’ worth of organic nitrogen, as compared with ground limestone.  That this much liberated nitrogen was essentially wasted and lost is evidenced by the fact that larger crops were produced where ground limestone was used than where burned lime was applied.