96 



THE PRINCIPLES OF SOIL MANAGEMENT 



Ws=WwX (2.65 X (100 -P). 



Where Ws = Weight of given volume of soil. 



Ww = Weight of volume of water equal to volume of soil. 

 P = Per cent of pore space. 

 (100 P)=Per cent of volume occupied by soil. 



Or the following formula may be used, and is often 



more convenient. 



Ws=Ap. Sp.xWw. 

 Where Ws = Weight of soil. 



Ap. Sp.= Apparent specific gravity. 



Ww = Weight of volume of water equal to that occupied 

 by the soil. 



Table XVI 



1. Clean sand 



2. Coarse sand 



3. Medium sand 



4. Fine sand 



5. Sandy loam 



6. Fine sandy loam 



7. Silt loam 



8. Clay loam 



9. Clay 



10. "Gumbo" clay 



11. Puddled heavy clay (Poto- 



mac) 



12. Heavy pipe clay 



13. Old pasture clay loam (Roth- 



amsted) 



14. Cultivated soil, clay loam 



(Rothamsted) 



15. Hagerstown loam 



16. Janesville loam 



Weight per 

 acre foot 



Lbs. 



4,800,000 

 4,356,000 

 4,200,000 

 4,080,000 

 3,550,000 

 3,590,000 

 3,400,000 

 3,330,000 

 3,180,000 

 3,000,000 



3,820,000 

 2,540,000 



3,100,000 



3,900,000 

 3,940,000 

 3,640,000 



One kilogram =2.2 pounds. 



