202 Journal of Agricultural Research voi. iv. no. 3 



but three reported investigations in all branches of biology, so far as we 

 are aware, which testify to the existence of antagonism between anions, as 

 pointed out by the senior author in one of the papers above cited (3). 

 Two of these were carried out with animals by Moore (11) and Neilson (12) 

 and date back several years. The third is that by Miyake (10) above 

 referred to, which appeared after nearly all of our work was completed 

 and after the statement made by the senior author (4). Our experiments 

 and results therefore constitute a pioneer effort in a virgin field. It is 

 perhaps needless to add that the practical significance of these results 

 when viewed from the standpoint of their bearing on the possible utility 

 of alkali soils for crops is of great moment. 



GENERAL DESCRIPTION OF THE EXPERIMENTS 



The experiments were carried out in the greenhouse and the plants 

 were grown in 8-inch paraffined pots. The soil employed was a clay- 

 adobe type found on the campus of the University of California. The 

 plant employed for the experiments was a selected strain of barley 

 (Hordeum spp.). Quantities of soil equivalent to about 5 kg. on the 

 basis of dry weight were mixed with the necessary salts, as indicated in 

 the tables, and placed in the pots. The salts employed were the com- 

 monest of those of alkali lands — namely, sodium chlorid (NaCl), sodium 

 sulphate (Na2S04), and sodium carbonate (NajCOg). For the purpose 

 of strengthening the value of our results, two crops in succession were 

 grown in the same pots, allowing the soil a rest period of about three 

 months. Eight seeds were planted in each pot and the plants were later 

 thinned to four to the pot. Water was supplied in quantities as nearly as 

 possible approximating the amount necessary to maintain optimum 

 moisture conditions. Duplicate pots were arranged to represent every 

 one of the treatments. It may be frankly remarked here that results 

 obtained in many of the duplicate pots were far from satisfying. ' We can 

 not, however, see how these differences, which are brought about by 

 inherent individual plant variations, and by slight differences in the 

 physical condition of the soil in the different pots, could have been 

 avoided. We do not consider our data, therefore, of absolute value and 

 realize further that variations in the technique of our experiments might 

 have yielded better results. Despite all that, however, mixtures of 

 salts allowing the interaction of different anions have permitted, even 

 under much higher osmotic pressures, so much better growth than in 

 smaller concentrations of a single anion only that we feel fully justified 

 in claiming our results to be proof of the undoubted existence of antag- 

 onism between anions. Indeed, that is the only claim put forward for 

 our data, but as to its validity we can not see any objection. All other 

 explanatory data are given in the following tables, which are discussed 

 separately and more in detail. 



