602 A GRICUL TURE. 



in the shape of animal manure, all the crops take away from the 

 soil. 



FERTILIZERS, AND WHERE THEY COME FROM. 



We have seen that the elements most generally wanting in 

 old, worn soils are potash, phosphorus, and nitrogen. Now let 

 us learn more about these, and where we get them from. 



Potash. Potash is found largely in the ashes of plants, and 

 constitutes one of the chief sources of food, supplied by wood 

 ashes from our fires, when spread on the land. Potash, as it 

 exists in ashes, is very easily dissolved in water, and if the 

 ashes have been leached with water for the purpose of getting 

 lye to make soap, very little potash will be left in them, and 

 they are then mainly valuable for the lime that may be left in 

 them. Potash also is found in other combinations, mixed with 

 common salt dug out of the earth ; mostly in Germany. It is 

 largely imported in these potash salts, which are sold under the 

 names of kainit, sulphate of potash, muriate of potash, sylvanit, 

 etc. In red-clay soil, on granite formations, there are usually 

 plentiful supplies of potash, combined with silica in the shape 

 of silicate of potash, and we get hold of this potash by adding 

 sulphate of lime or plaster, as it is called. By this means a 

 new combination, sulphate of potash, is made, which is more 

 easily dissolved by water than the silicate, and plants get it. 

 All rocks containing feldspar and mica have a great deal of 

 potash in them, and as these become decomposed the potash is 

 washed down into the soil. Potash is necessary to all plants, 

 and particularly favors the growth of clover and other plants of 

 the pea family, which help the soil in other ways. 



One of the most valuable sources of potash, in the South, is 

 the ashes of cotton-seed hulls, made at the oil mills. 



Phosphorus. We get this element in our fertilizers from 

 various sources. It exists in large quantities in the bones of 

 all animals, in the shape of phosphate of lime, which gives 

 ground bones a high value as a manure. It is also found in bone 

 charcoal, used by sugar refiners. The chief source of phosphate 

 of lime is the phosphate rock, which is found in large beds in 

 the coast region of North Carolina, South Carolina, Florida, 

 and Alabama. The largest supply of this material is dug in 



