EXERCISE A-7. TO DETERMINE THE AMOUNT OF 

 ORGANIC MATTER IN DIFFERENT SOILS. 



Equipment: Balance; small porcelain or tin dishes; 

 soil samples; gas burner or alcohol stove. 



Method: Place a teaspoonful of fine dry soil in a 

 dish. Put the dish on the left-hand pan of the balance 



Wick 



niass or Metal Tube 



Cork 



Fig. 5. — Small Alcohol Stove Made from an Ink Bottle or Oil Can. 



and add weights to balance it. Now heat the sample over 

 the flame until all the organic matter has been consumed. 

 Take care that the same weights are on the right-hand 

 pun of the balances and return the dish containing the soil 

 to the left-hand pan. 



How does this weight of the sample compaie with its 

 previous weight? How do you account for this difference? 

 Add dry leaves or cut straw until the pans are again in 

 balance. What does this added material represent? 



Discussion: Soils vary greatly in the amount of or- 



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