EXERCISE No. 58 

 PLOWING-UNDER ORGANIC MATTER 



Object : To illustrate the effect of plo wing-under organic 

 matter. 



Material: Two lamp chimneys, a quantity of dry fine 

 soil, some finely cut straw or chaff, some well rotted straw, 

 and some manure. 



Method: Tie a cloth over the bottom of each chimney. 

 Fill each chimney three-fourths full of soil. In one put an 

 inch of cut straw, pushing it compactly together. In the 

 other put an inch of the rotted straw likewise pushed to- 

 gether. To each add enough fine soil to fill the chimney. 

 Set each chimney in a pan in a half inch of water. Allow 

 them to stand for a few days. 



Conclusion: Note the rise of the water. Does it pass 

 through the straw as quickly as it does through the rotted 

 material? Why? The straw and rotted material represent 

 material plowed under and lying in the bottom of the furrow. 

 The soil on top represents the furrow slice. In which con- 

 dition do you think a crop would suffer least from dry 

 weather? When should strawy manures be plowed under? 

 When should new ground be broken up? Should spring or 

 fall be chosen for these purposes? Why? 



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