PEACTICE 10 



Determination of the Apparent Specific Gravity of Surface 

 Soil Under Field Conditions. 



Take a tube* provided for the purpose and force it into the ground 

 to the depth of six inches. Bemove soil to a weighed pan and dry in 

 the oven at 100° C. for at least ten hours. Find volume of the soil 

 taken and divide the weight of the water-free soil by this. The re- 

 sult will be the apparent specific gravity. 



The apparent specific gravity of soils in the field may be taken as 

 an approximate indication of the tilth, since the better the tilth the 

 less the apparent specific gravity for the same kind of soil. This is 

 due to the fact that soils in good tilth are looser on account of the 

 presence of a larger percent of organic matter and better granulation. 

 The apparent specific gravity of a continuously cropped soil is higher 

 than one having proper rotations. Why? 



What would be the weight of a cubic foot of soil under the above 

 conditions? 



♦An iron or brass tube three inches in diameter with a cutting: edge. Very heavy 

 galvanized iron will do. 



