. r ). r )0 EXPERIMENT STATION RECORD- 



absorptive power of soils for salts carried in solutions which are brought in contact 

 with them." 



In case of the Janesville loam "less phosphoric acid was recovered from each of 

 the four depths than was recovered from the soil when washed in distilled water, 

 while at the same time more silica was indicated by the method. If the reliability 

 of the method is admitted, it follows that treating this soil with the salt solutions 



used resulted in fixing in the soil not only all the phosphoric acid added but a < - 



siderable per cent of that which could he recovered with distilled water in contact 

 but 3 minutes; the lime, however, appears to have suffered but little change. 



"Potash became fixed in increasing amounts with the depth and in each case the 

 soil took on from 3 to 4 times the quantity recovered with distilled water; while of 

 magnesia the amounts absorbed from the solution are in no case quite equal to those 

 originally recovered with the distilled water. 



"The absorption of SO + was large, and the results, in themselves, also indicate an 

 absorption of nitric acid, although there is more reason to doubt these values on 

 account of the large amounts of chlorin present which had to be removed before the 

 determinations could be made, and on account of the possibility and even proba- 

 bility of denitrification having taken place. The chlorin, like the lime, remains 

 practically unchanged.' ' 



With the Hagerstown loam "the results are in some ways very different from 

 those just cited. In but one case was quite all the phosphoric acid removed from 

 the solution, but the solution was a little stronger as used on this soil. Silica was 

 more soluble in the salt solution than in distilled water, but not as much so as in 

 the Janesville loam, except in the third and fourth feet. 



"The lime behaved very differently, except in the fourth foot, very large amounts 

 of it going into solution in the first and second feet, while in the fourth absorption 

 occurred. 



"The different depths absorbed the potash very unequally, the surface foot taking 

 nearly double what the second took. 



"In the case of the sulphuric acid, too, there is a strong contrast, very much larger 

 amounts having been absorbed, except in the second foot, where a notable amount 

 went into solution from the soil itself." 



When the contact of the solution with this soil was increased to 72 hours instead 

 of 24 the soil increased the amount of phosphoric acid absorbed, "adding to what 

 they already had nearly 140 parts per million for all 4 ft. ; but at the same time they 

 appear to have lost from 8 to 37 parts of silica. 



"Sulphuric acid, contrary to the observations of the earlier investigators cited, 

 was absorbed in very large amounts by all 4 ft. at the end of 72 hours, although, at 

 the end of 24 hours, the duplicate determinations on the second foot showed a solu- 

 tion from that soil of 44 and 42 parts per million. 



"The large apparent absorption of nitric acid by the soil of the surface foot may be 

 due to denitrification. 



"The first, second, and third feet lost lime, as would be expected from earlier 

 observations, until the end of twenty-four hours, and, except the third foot, to the 

 end of 72 hours. The fourth foot, however, absorbed an increasing amount to the 

 end. 



"Both potash and magnesia were absorbed and the potash in larger amounts, 

 as was to be expected; but after 24 hours the surface foot gave back to the solution 

 again large amounts of both bases. 



"While the indicated absorption of chlorin is small, compared with other things, 

 we believe it is too large to be set aside as due to errors of method and irregularities 

 in manipulation." 



In experiments with a manure solution to which potassium nitrate was added, it 

 was observed "that all soils absorbed large amounts of potash from the solution 



