136 MANURES. 



vor to show in a simple manner the best means of 

 managing them in practical farming. 



AL K A L I E 



POTASH. 



Potash is often deficient in the soil. Its de- 

 ficiency may have been caused in two ways. Either 

 it may not have existed largely in the rock from 

 which the soil was formed, and consequently is 

 equally absent from the soil itself, or it may have 

 once been present in snthcient quantities, and been 

 carried away in crops, without being returned to the 

 soil in the form of manure, until too little remains in 

 an available form for the requirements of fertility. 



In either case the deficiency must be made up ; it 

 may be supplied by the farmer in various ways. 

 Potash, as well as all the other mineral manures, is 

 contained in the excrements of animals, but not (as 

 is also the case with the others) in sufficient quantities 

 to restore the proper balance to soils where it is 

 largely deficient, nor even to make up for what is 

 yearl}' removed with each crop, unless that crop (or 

 its equivalent) has been fed to such animals as 

 return all of tlie fertilizing constituents of their food 

 in the form of manure, and this to be all carefully 

 preserved and applied to the soil. In all other cases, 

 it is necessary to apply more potash than is contain- 

 ed in the excrements of the animals of the farm. 



^Vood ashes is generally the most available source 



