124 FERTILIZERS ON SANDY SOIL — SMITH. 



Potassium occurs in the form of silicates, especially hydrated 

 silicates. It is not abundant. 



A discussion of the other constitutents is not required in this 

 paper. 



" From a great nund;)er of experiments made Ijy Way, Liebig, 

 and many others, it seems to be established as a general fact that 

 all tillable fields are able to decompose salts of the alkalies and 

 alkali-earths in a state of solution in such a manner as to retain 

 the base together with phosphoric and silicic acids, while the 

 hydrochloric, nitric and sulphuric acids remain dissolved in union 

 with some other base besides the one with which they were ori- 

 ginally dissolved." 



This power varies in regard to the time required, the com- 

 pleteness of the absorption, and the quantity absorbed. It is. 

 increased by adding bases to the soil and diminished 1 )y treating 

 the soil with acids. It is proljably due to hydrated double sili- 

 cates. It is a part of good farming to increase tl^em. We find 

 them very abundant in the rocks around the Bay of Fundy and 

 possibly they may in a measure account for the fertility of our 

 marsh lands. 



It may also be added that when one base is introduced into a 

 soil it usually, more or less, displaces some other base, but it has 

 not been shown that this invariably follows. Ammonia is least- 

 readily displaced and potassium follows next. 



Phosphates are probably retained by the soil by the produc- 

 tion of insoluble doul)le phosphates. 



Bases may be retained Ijy the formation of double salts, especi- 

 ally with iron hydrates. 



The effect of Fertilizers and Manure upon the Soil, 



The probable effect of the application of ammonia salts to the 

 soil would be to slightlj^ increase its absorptive power. This 

 would be still more marked with potassium compounds and 

 SDilium nitrate — the only form in which we apply nitrates. 

 Most of the ammonia from manure is converted into nitrates, but 

 how far this is true of ammonia salts is not known. Phosphates 



