2o8 



Journal of Agricultural Research 



Vol. IV, No. 3 



soil. This is in striking contrast to the results given in Tables II and III, 

 which are based on toxic properties of given quantities of sodium chlorid 

 that are shown to be definite and constant in Table I. 



Table IV. — Results of experiments on antagonism between sodium carbonate and sodium 



sulphate 



ANTAGONISM BETWEEN CALCIUM SULPHATE AND SODIUM SULPHATE 



While this paper was intended primarily to deal with results obtained 

 with the interaction of anions of the common alkali salts, the antagonism 

 between which has been above estabhshed, other interesting factors re- 

 lating thereto deserve brief consideration here. Questions naturally arise 

 in connection with such work involving the relative efficiency of different 

 salts in counteracting a given toxic salt. Is it, for example, reasonable, 

 on the basis of Loeb's experiments (7, 8), to suppose that bivalent ions 

 like those of calcium would be more efficacious in the antagonism of 

 salts with a monovalent cation than another salt with a monovalent 

 cation? This is a practical question of great importance, so far as the 

 subject under discussion here is concerned. For example, it is of im- 

 portance for us to know whether sodium sulphate, which occurs in such 

 large quantities in our alkali soils, at times singly and at times together 

 with other salts, can be prevented from reacting deleteriously to plant 

 growth in those soils by the application of gypsum. The latter salt of 

 calcium is now much used in practice for purposes of counteracting the 



