132 CHARLES B. LIPMAN 



Of course all of these remarks are not to be construed as in 

 any wise derogatory to the practice of Uming soils. That, as is 

 plainly evident to all of my colleagues, is quite another story. 

 That liming is necessary on many soils and perhaps one of the 

 important practices in soil management, is beyond cavil. It is 

 only liming or ''magnesiaizing" (if I may be allowed to coin a 

 term) for the purpose of establishing certain ratios of hme to mag- 

 nesia in the soil that I object to. 



Unfortunately, the space of this paper will not allow of a 

 fuller critical discussion and analysis of the question of the lime- 

 magnesia ratio and of the investigations and results put forward 

 in support thereof or antagonistic thereto. The following table, 

 however, and the discussion which I have given, appear to me to 

 point pretty clearly to the untenable nature of Loew's hypothe- 

 sis for either theoretical or practical purposes. The toxic effects 

 of magnesium in excess or when apphed to soil, not in excess, 

 are easily explained on the basis of its own specific physiological 

 properties, and need no introduction of ''ratio" considerations 

 between itself and calcium to explain them. The non-toxicity 

 of calcium in large quantities, as has been shown time and again 

 in investigations above reviewed and others which can not here 

 be mentioned, renders questionable Loew's attempts to show 

 that calcium in excess, especially in its carbonate form, is toxic, 

 or at least in such a way as magnesium compounds are toxic. 

 That magnesium compounds may be added to excessive quanti- 

 ties of calcium and overcome ill effects of such excessive quanti- 

 ties is rendered at least somewhat questionable by researches 

 which I have reviewed, and where favorable effects are noted, 

 explanations can be made on many other bases which do not 

 require the assumption of something so entirely artificial as the 

 necessity for a proper lime-magnesia ratio. Likewise, in the ad- 

 dition of calcium to excessive quantities of magnesium there is 

 even more opportunity for explaining beneficial effects which 

 usually follow such appUcations in many other ways, as already 

 indicated above, than by assuming that there is a necessity for 

 a certain lime-magnesia ratio. Calcium and magnesium are of 

 course essential elements in the growth of plants. Their some- 



