660 STATE BOARD OF AGRICULTURE. 



These data show that with the exception of the Ch'de sandy loam the 

 virgin soils have a nnich greater eonrentration of soil solution after len 

 days, than do the cropped samples. The increase varies from twice 

 as much in the case of Miami silt loam to three times as much in the 

 case of Miami very fine sandy loam. 



At tlie expiration of the thirty-day period a tendency for the concen- 

 trations of the solutions of the cropped and virgin soils to approach each 

 other is noticeable in the case of the samples of Miami silt loam. This 

 is brought about in one case In^ a further increase of the soluble salts in 

 the cultivated soil and in the otlier case b}- a decrease in the salt con- 

 tent of the virgin sample. There is still quite a distinct excess of soluble 

 material in the virgin samples of sand and very fine sandy loam over that 

 of the corresponding cropped soils. 



In only one case is there a distinct increase in the amount (»f soluble 

 material present after 30 days over tliat found after 10 da^s wliile in 

 four cases there is an appreciable decrease. This phenomenon is (piite 

 interesting and will be referred to later on. 



Tlie data presented indicate that while there is a marked tendency for 

 both cropped and virgin soils to show an increase in solulde salt contuit 

 after standing at the water content used, the solubility of the virgin 

 soils on the whole is greater than is that of the cropped soils. 



Medium Water Content. For these experiments 20 grams of soil 

 were placed in freezing point tubes and 10 c.c. of distilled water added. 

 In the case of the heavy soils this amount of water was sufficient to make 

 a thick mud while with the lighter loams and sands water stood over 

 the surface of the soil after settling. 



As in the previous series the freezing point lowerings were determined 

 one hour after adding the water and again after standing ten and thirty 

 days, respectively, at a tem]ierature of 25° O. The same precautions 

 were taken to i)revent the accumulation of carbon dioxid or otlier gases. 



Tlie following table shows the results obtained with the soils from 

 Ingimm county. 



