PRACTICE XXVIII 



EFFECT OF ORGANIC MATTER ON RISE OF CAPILLARY WATER 



A class exercise to be arranged by the instructor. 



It is best to use glass tubes 1^ to 2 inches in diameter. 



Fill, compact, and set up, as in the preceding practice : 



Tube No. 1, gray silt or gray silt loam. 



Tube No. 2, gray silt or gray silt loam 95 per cent plus 5 per 

 cent peat. 



Tube No. 3, gray silt or gray silt loam 90 per cent plus 10 per 

 cent peat. 



Tube No. 4, gray silt or gray silt loam 85 per cent plus 15 per 

 cent peat. 



Tube No. 5, gray silt or gray silt loam 80 per cent plus 20 per 

 cent peat. 



Tube No. 6, gray silt or gray silt loam 65 per cent plus 35 per 

 cent peat. 



Tube No. 7, gray silt or gray silt loam 50 per cent plus 50 per 

 cent peat. 



Tube No. 8, peat. 



Tube No. 9, a virgin sod. 



Tube No. 10, heavily cropped not rotated, the same as the 

 virgin soil and collected as near to it as possible. 



Compact as uniformly as possible. Take the readings at the 

 same intervals, record and plot curves as in the preceding prac- 

 tice. Plot a separate set of curves for the virgin and the heavily 

 cropped soils. 



REFERENCES. 



The same as given under Practice XXVI. 



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