May, '14] GRANITIC SOIL POTASSIUM. 31 



It appears, however, that the clover plant can secure enough 

 potassium from the soil to produce a crop containing a normal 

 amount of potassium. 



From a practical standpoint, the use of potassium fertilizers 

 on these soils, for the production of grass, cannot be recom- 

 mended. At best and under the most favorable conditions, the 

 most that can be expected is the return of a dollar for the one 

 expended. Therefore the practice of top dressing grass land 

 with potassium fertilizers cannot be expected to be profitable. 



The foregoing data show that large yields have been obtained 

 without the use of any potash in the fertilizers and that the com- 

 position of the crop is not materially changed by its use. It is 

 evident that, under favorable conditions, the potassium which 

 is in the soil is sufficiently soluble to supply the needs of the crop. 

 Frequent and thorough cultivation, together with rotation of 

 crops, tend to create favorable conditions. The use of nitrate of 

 soda, sulfate of ammonia, acid phosphate, and acidulated fer- 

 tilizers tends to increase the solubility of the soil potassium. 



