Relations of Manganese and Other Cations 



193 



The addition of N/25 MnCl2 to this particular soil results in great 

 injury to pea seedlings. The growth of tops is only 6 centimeters and 

 the root growth is likewise depressed. The presence of N/25 CaCl2 

 reduces the injury from the manganese, as the average growth of tops in 

 this culture is 19 centimeters and the root growth is also more extensive. 

 These results are a.t variance with those obtained by pineapple-growers 

 in Hawaii, as Kelley (1908) reports that the addition of lime or other 

 fertilizers is not effective in counteracting the injury resulting from 

 manganese. 



Potassium and manganese 



Potassium and rnanganese {distilled water) . — Since calcium is relatively 

 effective in antidoting manganese, it is of interest to ascertain whether 

 other metals as cations counteract this injurious action. By means 

 of several sets of experiments it has been determined that mutual 

 antagonism exists between manganese and each of the following: potas- 

 sium, sodium, and magnesium. N/500 MnCl2 prevents growth of wheat 

 seedlings and N/2000 is extremely toxic. This deleterious action is over- 

 come by the presence of N/50 KCl. A weaker solution of potassium, 

 N/500, is antagonistic toward manganese, but to a less extent than more 

 concentrated solutions. 



N/50 KCl is very injurious to roots of wheat seedlings. The presence 

 of either N/500, N/2000, or N/5000 MnCl2 counteracts this toxicity. 

 An examination of Table 11 bears out the above statements: 



TABLE 11. Experiment with Wheat, Continued for Thirty Days. Data for Eight 



Plants 



Composition of solution 



Tola! 



ireen weight 



(grams) 



Average length 



of tops 



(centimeters) 



Average length 



of roots 



(centimeters) 



N/50 KCl 



N/50 KCl + N/500 MnCU. . . 

 N/50 KCl+N/2,000 MnCk.. 

 N/50 KCl + N/5,000 MnCls. 

 N/500 KCl+N/2,000 MnClz 



N/2,000 MnCl2 



Distilled water 



0.65 



0.85 



1.50 



1.20 



0.80 







0.55 



6 

 8 

 9 

 11 

 9 

 2 

 6 



Potassium and manganese {N/1000 CaCk). — Under ordinary green- 

 house conditions pea seedlings, in distilled water or in full nutrient solu- 



