THE LIME-MAGNESIA RATIO 133 



what similar chemical nature does not give us leave, however, to 

 place them in a similar physiological category, and indeed num- 

 erous investigations point to their total dissimilarity so far as 

 that is concerned — Loew's own investigations being perhaps the 

 most important in support of that idea. But despite all of that, 

 it is inconceivable to any one w^ho has in view the modern de- 

 velopments of plant physiology and physical chemistry, as well 

 as the modern views on the soil and its solution, why it should be 

 any more assumed that a proper ratio between calcium and mag- 

 nesium is necessary than that a proper ratio between calcium 

 and potassium and between calcium and iron and between cal- 

 cium and other essential elements in the growth of plants, are 

 necessary. A proper understanding of and consideration in con- 

 nection with this subject of the general principle of antagonism 

 between ions is far more pertinent in this connection, observing 

 how generally the principle applies, in at least partly accounting 

 for beneficial results from the application of lime to magnesia, 

 and for the change thus wrought in their relationship in soils. 

 The balance of the effects which are not accounted for by antago- 

 nism between the ions within the soil solution itself, may so 

 far as soils themselves are concerned, be just as easily explained 

 on the basis of the effects of the applications on the physical 

 condition of the soil, on the chemical reactions following in the 

 soil, on the bacterial flora, on the protozoan fauna, and on other 

 faunas within the soil, as it can be by introducing the rather far- 

 fetched notion of the necessity of a certain lime-magnesia ratio. 



In brief, the writer believes. that he has shown by a review of 

 some of the most important investigations in the field, that in 

 the first place there is little or no evidence in support of the 

 necessity to plants for a proper lime-magnesia ratio in soils, which 

 is specific for certain groups of plants. In the second place, 

 that when certain favorable effects are noted which appear to 

 indicate that they follow from the adjustment of the ratio of 

 lime to magnesia, such favorable effects can easily be explained 

 on man}' other grounds which do not call at all for the introduc- 

 tion of the hypothesis of the lime-magnesia ratio. 



