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PRACTICE 23 



Eefbct of Organic Matter on Kise of Water. 



Class exercise in which each member of the class is to take daily 

 observations on the height of the water in the tubes and note effect 

 of organic matter on rise of water. 



After tying a cloth firmly over the ends of two glass two-inch tubes, 

 18 inches long, fill them to the height of one foot with soil compacted by 

 letting the tube drop four times on a book for a distance of six inches 

 for every six inches of soil put in the tube. 



In one tube put about an inch of cut straw or sawdust, in the 

 other about a half inch of well decomposed manure or peat. Fill the 

 tubes with soil. Place the ends of the tubes in a tray and note the 

 effect of the organic matter. 



What is the effect of plowing under poorly rotted manure in the 

 spring? 



What advantage in this respect in fall plowing? 



