FERTILIZATION. 133 



soils that the crop does not want and cannot assimilate, or 

 perhaps the soil may already possess them in abundance. In 

 feedins: an animal we first endeavor to ascertain what it 

 requires, and if we have sufficient quantities in our barns, we 

 do not pay a large profit on some perfect food , but rather, if 

 we find we are wanting in some particular kind, we purchase 

 that alone, and not mixed with several others that we do not 

 want or already have. Farmers are often imposed upon in 

 this matter on account of their inability to tell what they 

 have in excess, or the element of which they stand in need. 

 It is a safe rule, however, not to buy until we know what we 

 want, and then to know what we are buying. And of all 

 the varieties of plant-food in the market, there is none the 

 ■qualities of which the common farmer should be a better 

 judge of than stable manure. When it is expedient to buy 

 chemical fertilizers it will be well to bear in mind that how- 

 ever bulky they may be, or whatever may be their color or 

 odor, their value depends practically upon the availability 

 and solubility of three elements in their compound, one of 

 which is nitrogen, the most costlv of the three. I have been 

 at a loss to learn how the common farmer can conduct any 

 experiments with this element alone that can result in any 

 considerable advantage. We are told that in its pure form 

 it is colorless and odorless ; neither are the " doctors" fully 

 ^agreed upon just how it enters the plant strncture. It can- 

 not be handled unless confined in some powerful base, and 

 then we are at a loss where to place it to make it most 

 available. 



I have decided not to invest largely in this shy element 

 until we are better acquainted, getting what I can, however, 

 from stable manure and cotton-seed meal, both of which are 

 rich in nitrogen. The purely nitrogeneous manures are not 

 considered as essential as formerly, excepting where an ex- 

 x^essive leaf development is desired. 



Another of the three wanting elements, phosphoric acid, 

 may be obtained from ground bone, or the phosphatic rocks, 

 which are composed of the bones and teeth of prehistoric 

 animals. 



Nearly all of this rock quarried in Canada, and about 

 three-fourths taken from the South Carolina beds, is exported 



