156 



If the computed amounts of change which occurred in these 

 soils, as the result of contact with the solution, are brought to- 

 gether they appear as shown in the next table. 



Amounts of change in the salt content of 8 soil types resulting from 

 contact with a manure solution containing potassium nitrate. 



From this assembling of the data it is seen that all soils have 

 absorbed large amounts of potash f rom| the solution used, but the 

 .Norfolk Sandy Soil least and less than one-eighth that absorbed 

 by the Janesville Loam, which produced the heaviest yields. 

 While potash has been absorbed by all soils, in every case has 

 lime gone into solution, and in larger quantities from the four 

 soils which have given the largest amounts of lime from treat- 

 ments with distilled water. So, too, have the four soils, yielding 

 largest amounts of magnesia, under repeated washing, given this 

 base over to the solution ; but in three other cases magnesia was 

 absorbed. 



Very large amounts of nitric acid have failed to appear in the 

 solution after contact with the soils and it has clearly been held 

 back or transformed. Denitrification, in the biological sense, win- 

 not have taken place to this extent, (1) because the soils them- 

 selves have been repeatedly dried at 120 O, and came to this 

 experiment warm from the dry oven; (2) because sufficient 

 time did not intervene for so much de-nitrification to have oc- 

 curred as the result of vital activity. We were not able, with our 

 reduced force at this time, to make tests for either ammonia or 

 nitrous acid. The solution was analyzed in duplicate and there 



