ABSORPTION OF SALTS BY SOILS. 163 



It should be recalled here that it is the potash ingredient of 

 the soil which has shown the closest relation to yields as regards 

 quantity recovered from the soil ; and in all of these series the 

 potash has been removed from solution in largest amounts by 

 those soils which have produced the largest yields. 



A limit appears to have been reached in this series where no 

 determined ingredient was forced into solution from the soil, 

 but rather that something from all was held back. This has not 

 been the case in any other series presented. 



The large irregularities shown in this series are, doubtless, to 

 a considerable extent, due to the high concentration of the solu- 

 tion used, which required large dilutions before readings could 

 be made by the methods. The aliquots have been large, there*- 

 fore, and any error of setting greatly multiplied. The methods 

 used are, of course, not adapted to such strong solutions, but 

 they were the best which could be employed under the circum- 

 stances. 



ABSORPTION OF SALTS BY BLACK MARSH SOIL. 



Samples of soil were collected from a black marsh soil under 

 three different crop conditions, (1) where corn was very poor; 

 (2) where there was a fair average crop, and (3) where the corn 

 had all died, possibly because the soil had been too wet, and 

 was at the time supporting a rank growth of weeds. 



These soils were treated with two different solutions the usual 

 time for washing soil samples, and by the same method, except 

 that -in these cases solutions instead of distilled water were em- 

 ployed. 



In the next table there are given the results secured from one 

 of these absorption series, together with other data. 



