June IS, 191S Antagonism between Anions as Affecting Barley 213 



perhaps in part explain the peculiar behavior of this salt in the toxicity 

 series which we have discussed, as well as its behavior in the antagonism 

 series; for small quantities of sodium carbonate, which evidently are all 

 that can be counted on to remain in the soil any length of time, might well 

 act as stimulants rather than as toxic agents. This view is to be con- 

 sidered in conjunction with those above discussed on the behavior of 

 sodium carbonate. However that may be, the slight recovery of this 

 salt effected by us from the treated pots would seem to support even 

 more strongly the view expressed above, in which an analogy is drawn 

 between the behavior of sodium carbonate and that of magnesium 

 carbonate (MgCOg) as first explained by Maclntire (9). 



PRACTICAL CONSIDERATION OF THE) EXPERIMENTS 



It appears plain, in view of the results of Miyake (10) and ourselves 

 (3-6), that the establishment of the existence of antagonism between 

 anions is invested with at least a certain measure of practical importance. 

 In the State of California, as well as in several other of our Western States, 

 very large acreages of land are to be found in which the predominance of 

 one salt, frequently Glauber salt or common salt, makes impossible 

 successful cropping. It would appear from the above results that it 

 would not be a difficult matter to establish a mode of treatment which 

 would involve the neutralization of the toxic effects of any one or even 

 two of the alkali salts by another alkali salt. Thus, we frequently find 

 soils containing, besides small quantities of other salts, about 0.5 per cent 

 of sodium sulphate. It is clear that in a heavy soil, at least by additions 

 of gypsum at the rate of about 2 tons to the acre or common salt in 

 smaller quantity, we could change the soil from a very poor into a normally 

 producing one, despite the fact that we have very considerably increased 

 the total salt content thereof. 



THEORETICAI^ CONSIDERATIONS OF THE EXPERIMENTS 



Several questions of interest, at present merely in their theoretical 

 aspects, arise from the foregoing discussion and the results which form 

 the basis thereof. 



The differences in yields of two successive seasons in the same soils and 

 pots are probably to be largely, though not entirely, attributed to tempera- 

 ture and atmospheric variations. To judge from the data submitted in 

 the tables, the change in the soil's condition from one season to another 

 has operated only in a minor way toward crop improvement. On the 

 other hand, it is not impossible to regard the results as indicative of the 

 opposite condition if particularly great stress is laid on the yields of the 

 control pots during the second season. 



The causes of antagonistic action still remain the topics of investigation 

 most difficult of solution. Our results can only point indirectly to pos- 

 sible solutions of this important question. It is, however, interesting to 



