EXERCISE A-22. TO SHOW THE EFFECT OF A LOOSE 

 SURFACE UPON THE RATE AT WHICH THE RAIN 

 WILL SOAK INTO THE SOIL. 



Equipment: Two quart cans; a graduate; sufficient 

 moist garden or field soil to fill the two cans. 



Method: Fill the two cans to within one inch of the 

 top with the moist soil. Firmly compact the surface of 

 the soil in one can and leave the surface of the other loose. 

 Pour an equal amount (4 ounces) of water on the surface 

 of each and note the time it takes it to disappear into the 

 soil. Which takes in the water more rapidly, the loose or 

 the compacted surface? 



Discussion: When rain falls upon the surface of a 

 field a part of the water soaks into the soil and another 

 part runs off the surface. If the surface is dry and hard, 

 a very large part of the rain runs off and only a small quan- 

 tity enters the soil. The part which runs off the surface 

 is not only entirely lost to the crop, but it also washes the 

 surface and carries away with it a large amount of plant 



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