THE LIME-MAGNESIA RATIO 125 



To add to all these possibilities of quite different effects of an 

 addition of calcium or magnesium one to the other, when either 

 one is present in toxic quantity, we may still further consider that 

 in some of the investigations above reviewed it was found that 

 that not only the addition of calcium to magnesium or magne- 

 sium to calcium, but an addition of another material like potas- 

 sium nitrate, might very much improve the action of the antago- 

 nistic element of the two which we are considering, and a great 

 amount of evidence has been adduced from past experiments on 

 balanced solutions in plant growth which indicates quite clearly 

 that many elements can be used as antagonistic agents to many 

 others. Why not, therefore, merely regard the calcium as an 

 antagonistic agent to magnesium without involving the necessity 

 of a definite ratio between calcium and magnesium as being a 

 necessary condition for the successful growth of plants? 



The positive investigations further, despite their rather large 

 number, are by no means fully convincing in their evidence that 

 certain definite ratios of lime to magnesia are necessaiy for the 

 proper growth of plants because these ratios are found to vary 

 so much. In some instances, we have ratios varying from 1 : 1 

 to 1:2, to 1:3, for the same plants, whereas in others, we have 

 ratios which vary from 1 : 1 to 6.7 : 1 as in Konovalov's experi- 

 ments, for example. Then again, we have a wide variation in 

 ratios for different plants, some of them evidently requiring 

 much higher ratios of fimeto magnesia than others. Consider- 

 ing the wide diversity in soils upon which plants are grown and 

 the wide diversity in hme and magnesia contents and ratios in 

 those soils in all parts of the world, and that factors quite outside 

 of the calcimn-magnesium ratio in question must be taken into 

 account, is it at all likely that the lime-magnesia ratio exercises 

 so potent an influence on the welfare of plants in soils as Loew 

 and his followers would have us believe? 



In following the subject further, let us consider for a moment 

 the negative investigations. Here w^e find strikingly enough, 

 just as many investigations which cast doubt, and serious doubt, 

 on the necessity of certain definite ratios of lime to magnesia for 

 plants as those which favor the idea of the necessity for such a 



