6i8 



Journal of Agricultural Research 



Vol. XX, No. 8 



AVAILABILITY OF THE POTASSIUM IN ORTHOCLASE SOLUTIONS NOT 

 INCREASED BY BOILING THE SOLUTION 



The effect of boiling an orthoclase solution on the subsequent avail- 

 ability of the potassium is shown in Table II. In this experiment the 

 potassium content of the plants grown in the culture solution was com- 

 pared with that of the original seed. The analyses show that within the 

 errors of experiment the availability of the potassium was not modified 

 by boiling the orthoclase solutions. 



TABLE II. — Effect of boiling orthoclase solutions on the availability of the soluble potas- 

 sium 



AVAILABILITY OF POTASSIUM IN ORTHOCLASE SOLUTION NOT 

 INCREASED BY PRESENCE OF CARBON DIOXID 



Carbon dioxid is universally present in the soil solution. It is con- 

 sequently desirable to determine whether the availability of the potassium 

 in orthoclase may be measurably increased by the addition of carbon 

 dioxid to the solution. A culture solution of orthoclase with the solid 

 phase present was accordingly prepared, and a portion of this solution 

 was saturated with carbon dioxid. Plants grown in the two solutions 

 showed no difference in their potash content (Table III). It conse- 

 quently appears that a weak acid, such as carbonic acid, in concentra- 

 tions equivalent to those found in soil solutions, does not increase the 

 availability of the potassium in orthoclase. 



Table III. — Effect of carbon dioxid on availability of potassium in orthoclase 



