FIELD CROPS. 833 



be noticed if the plants were grown \n neutral or slightly alkaline media 

 remains for further investigation." 



Tabulated data are given. 



The influence of salts common in alkali soils upon the growfh of the rice 

 plant, K. MiYAKK {Jour. Biol. Chcm., 16 (lUIS), No. 2, pp. 235-^63).— From the 

 results of 2 experiments to determine the influence of single salts upon the 

 growth of rice seedlings the author concludes that *' the alkali salts under 

 examination act as agents both toxic and stimulating upon the growth of rice 

 seedlings, according to their concentrations. The toxic concentrations of mag- 

 nesium sulphate and chlorid, calcium chlorid, sodium chlorid and carbonate are 

 greater than l/lOO-normal while sodium sulphate and bicarbonate are greater 

 than fiftieth-normal. The highest stimulation is observed in the dilution of 

 1/500-normal for magnesium sulphate, 1/1,000- to 1/5,000-normal for mag- 

 nesium chlorid, 1/1,000- to 1/5,000-normal for calcium chlorid, fiftieth-normal to 

 1/100-normal for sodium chlorid, 1/100- to 1/500-normal for soilium carbonate 

 and bicarbonate." 



In studying the antagonism between the toxic effects of 2 salts upon the 

 growth of rice seedlings, the results of 10 experiments that included the use of 

 MgSO«, CaCl2, NazSO^, MgClz, and XaCl, showed that " the salts under exami- 

 nation, used separately, are very poisonous in tenth-normal concentration upon 

 the growth of the rice plant, but when the 2 salts are mixed with each other 

 in a suitable proportion, the toxic effect of each salt more or less completely 

 disappears. This result is of great importance in alkali soil investigations. 

 The antagonistic action of salts is due to that of the ions formed by the dis- 

 sociation of the salt. In general, divalent cations are markedly antagonized 

 by monovalent cations, but on the other hand, monovalent cations do not 

 strongly antagonize divalent cations. Among the divalent cations, calcium 

 shows a more marked antagonism than magnesium. The antagonism between 

 Cr and SO*", though it is small in comparison with that between cations, is 

 also present in no slight degree." 



In 14 experiments as to the antagonistic action of sodium and potassium 

 salts, which included NaXOa, KCl, KNO3, NaCl, K2SO4, and XaaSO*, the results 

 showed that " sodium and potassium salts are antagonized by each other. The 

 curve of antagonism between these salts shows 2 maxima and the location of 

 these maxima is almost constant, occurring at the point of the proiwrtion of 

 5:25. This coincides with the result which was observed by Osterhout on 

 wheat seedlings. The antagonism between these salts is due to cations as well 

 as anions. The antagonism between anions is small in comparison with that 

 between cations." 



In studying the antagonism between potassium and magnesium or calcium 

 ions, 2 experiments in which KCl, MgClz, and CaCla were used showed that 

 " potassium and magnesium or calcium salts are poisonous to the rice plant 

 when used separately but when mixed together in suitable proportion the poi- 

 sonous effect more or less completely disappears. The results coincide with 

 those of Osterhout and form an important factor in the question of soil 

 fertility." 



As to the possibility of barium and strontium replacing the antagonistic 

 action of calcium, 2 experiments in which MgCU and NaCl were used as the 

 toxic salts, showed that " the injurious effect of certain metallic ions ui)on the 

 growth of rice seedlings may be i)erfectly counteracted only by the presence of 

 calcium ions. Strontium ions can exert an Influence only slightly retarding the 

 toxicity of the metallic ions. Barium ion not only has no beneficial action but 



