48 Journal of the Mitchell Society [A^igust 



iron. The chlorine of kainit aids the passage of potash into the plant. 

 The sodium of kainit furnishes a base to combine with nitrates pro- 

 duced by nitrification, the resulting compound being not only non- 

 toxic, but stimulating and a direct plant food. The combination of 

 sodium with nitric acid reduces the amount of ferric nitrate which 

 may be formed. Kainit, therefore, supplies potash both directly and 

 indirectly ; reduces the amount of soluble iron ; and increases the non- 

 toxic nitrates. 



2. Nitrate of soda aids potash into the plant ; supplies a beneficial 

 nitrate ; and depresses nitrification so that an excess of ferric nitrate 

 is not presented to the plant. 



3. Acid phosphate retards the entrance of potash into the plant, 

 hence aids in the accumulation of toxic iron. 



4. Lime at the rate of 2 or 3 tons per acre has given better results 

 than more or less. This appears to be due to the synergistic effect of 

 calcium on potash. A smaller amount of lime is probably insufficient 

 for this purpose. A larger amount is not needed for this purpose and 

 probably stimulates nitrification with formation of excessive ferric 

 nitrate. There appears to be no direct relation between the effect of 

 lime and the lime requirement of the soil as determined by the Veitch 

 method. 



The effect of lime on the ridged land is not significant. Lime is 

 probably without value because the ridged land is aerated to a point 

 where it will not retain soluble iron. 



Ealeigh, N. C. 



