UK 

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CHAPTER V. 



POTASH I ITS ACTION ON THE SOIL IS IT ESSENTIAL TO PLANT 



LIFE ? KESULTS OF DIRECT EXPERIMENTS ITS NECES- 

 SITY MADE CLEAR SOURCES OF ITS SUPPLY LIME 



THE LIMING OF SOILS ITS CHEMICAL ACTION ITS AB- 

 SORBING POWERS ITS ACTION ON SULPHUROUS ORES 



ITS ACTION ON IRON ALUMINA AND PHOSPHORIC ACID IN 



THE SOIL NECESSITY FOR ITS ABUNDANT USE. 



The ashes of all plants, when submitted to analysis, are found to 

 contain potash in noticeable proportion, and hence that substance is 

 presumed to be a very active and essential fertilizing agent, although 

 its precise influence in the process of development is not rig- 

 orously known. 



It has been suggested that, once in the soil, it enters into a solu- 

 ble combination with the phosphoric acid to form potassic phos- 

 phate, and in that shape becomes absorbed by the roots of the 

 plants, the basic salt, however, remaining deposited in the various 

 organisms after the evaporation of the water. 



The doubts which have been expressed by many authorities as to 

 the utility of introducing potash into the soil as an active artificial 

 manure, induced Monsieur George Ville, when experimenting at 

 Vincennes, to devote his particular attention to this disputed point, 

 and although it cannot be said that his researches have added very 

 much to our information from a chemical point of view, the results 

 he obtained were of a sufficiently definite nature to warrant us in be 

 lieving that the growth of plants would be unhealthy, if completely 

 deprived of potash. 



