A CRITIQUE OF THE HYPOTHESIS OF THE LIME- 

 MAGNESIA RATIO 



CHARLES B. LIPMAN 



University of California, Berkeley, Cal. 



The time has come for agronomists, soil specialists, and plant 

 physiologists to scrutinize with a critical eye the whole situation 

 with respect to the subject of the lime-magnesia ratio in soils and 

 its relation to crop production. Much, too much, has already 

 been said and done on this subject in a practical way, affecting 

 the operations and ideas of farmers, to make it safe for us to go 

 on piUng up discussions with respect to it without pausing to 

 look back over all of our results and determine their significance 

 as appears rational in the light of the work thus far done. This 

 should be done at least to correct misimpressions and for the 

 purpose of formulating a clear and concise statement, based on 

 the best information which we have, to serve a^ a guide for the 

 rational man. The writer has therefore taken the liberty of 

 bringing together for the inspection of his colleagues, a review 

 of the results thus far obtained by investigators of this interest- 

 ing subject, and ventures in addition such critical remarks with 

 reference to them as appear, from close study and thought as 

 well as from his own experimental data, to be justified. That the 

 past and present status of the question in hand have been rather 

 alarming from their effects on soil management in certain quar- 

 ters is not stated above on the basis of hearsay. I have known of 

 measures employed in soil management in this state, based on 

 the theory of the lime-magnesia ratio as first enunciated by 

 Loew and later exploited by unscientific men, which to the ra- 

 tional-minded experimenter with soils and plants, appear to be 

 the veriest folly. Such should not be allowed to go on, without 



THE PLANT WORLD, VOL. 19, NO. 4, 1916 



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