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PRACTICE 12 



Determination of Porosity. 



first method. 



"Weigh the Nessler's jar or graduated cylinder. 



Use sand, loam, silt, clay and peat. 



Fill to the 50 or 100 cc. mark with soil not compacted and weigh. 

 Compute the amount of water-free soil in this, using the percent of 

 hygroscopic moisture determined in Practice 6. 



(Volume of soil x real specific gravity)-Wt. of water-free soil = nt Qf space 



Volume of soil x real specific gravity 



What effect does size of particles have on total amount of pore 

 space? 



Does the amount of pore space increase or decrease with the 

 amount of organic matter? 



Which of the soils have the largest pores? Does this mean the 

 greatest amount of pore space? 



