76 



MASS. EXPERIMENT STATION BULLETIN 165. 



Table II. — Milligrams of Ammonia absorbed from Ammoniion -sulfate 

 Solutions by 100 Grams of Air-dried Soil. 



[0 L ='plot 0, limed end; UL = plot 0, unlimed end, etc.] 



Plot. 



L, . 



UL, 



1 L, . 

 1 UL, 

 6 L, . 



6 UL, 



7 L, . 



7 UL, 



8 L, . 

 8 UL. 



Taking the plots as a whole we find that with an increase in the concen- 

 tration of the amnionium-sulfate solution used the amount of absorbed 

 ammonia increases. Comparing the amounts of ammonia absorbed by 

 soil from the different plots we find that the unlimed ends of plots 6 and 8 

 consistently show a smaller absorption than anj'' of the others, except in 

 one case with the strongest solution by soil from plot 8. The variations 

 in amounts absorbed on the remaining plots are within the hmits of pos- 

 sible error, on account of the concentration of the solutions employed. 



Absorption of Dyes. 



This difference in the absorption capacity of the different plots is less 

 strikingly shown by a study of the dye absorption. The dyes used were 

 aniline blue, aniline green, corraline and eosine. The method of procedure 

 was as follows : 10 grams of soil were shaken up with 100 cubic centimeters 

 of the dye and then set aside until the supernatant liquid was clear. Fifty 

 cubic centimeters were then pipetted off and compared with a standard 

 dye solution in a colorimeter. 



The eosine and corrahne were not absorbed by the soil in a measurable 

 quantity, if at all. One hundred cubic centimeters of the anihne blue 

 and aniline green in concentrations below 50 parts per milUon were entirely 

 decolorized by 10 grams of soil. The concentrations used were 50 and 

 100 parts per million. 



