44 SOIL AND SOIL PREPARATION 



Conclusion. How do earthworms modify the soil ? 

 What is the effect on the growth of the plants? 



Suggestion Drainage. Study the soils about the school 

 or home. When it rains, what sort of soils absorb most 

 water? On what kind of soils do puddles accumulate? 

 After a puddle has dried up examine the bed of its pool and 

 find out what kind of soil covers it. 



Fill several flowerpots with soils and pack them down 

 tightly. Then water them well and let them stand for 

 some time. Which soils let the water pass through most 

 readily? Which remain damp longest? Which crack in 

 drying? 



From your observations what kind of soil is best for let- 

 ting air and water down to the roots of plants ? 



Earthworms. Examine the surface of the ground early 

 in the morning and look for wormholes and worm casts 

 near these holes. How does the earthworm modify the soil ? 



Look for bits of leaves that have been dragged into worm- 

 holes by the worms. Show how worms benefit the soil (a) 

 by opening holes in it ; (6) by dragging down trash from the 

 surface ; (c) by bringing up the worm casts and leaving them 

 above on the surface. 



Farming. Why does the farmer sometimes sprinkle 

 sand or coal ashes over a clayey field before plowing it? 

 If you had a very sandy field, how might it be treated to 

 make it hold moisture better? Why? What effect on re- 

 tention of moisture would it have to spread leaf mold on 

 a field before plowing it? 



