Cultivation and Drainage 61 



2. Set a cup on each pan of a pair of scales and put the same 

 amounts of equally moist earth in each cup, making the scales 

 balance. Then pack the dirt in one cup and loosen the surface 

 of the dirt in the other. After a few days' absence, which cup 

 has become the lighter through loss of water? Why has this 

 cup lost the more water ? What does this suggest as to the cul- 

 tivation of a field? (Fig. 31.) 



3. To show the presence of air in soil, drop a clod into water 

 and notice the bubbles. 



4. Wet two spots of clay soil. Immediately work one spot 

 very thoroughly with a hoe. Let the other spot become nearly 

 dry and hoe it. Compare the condition of the two spots a few 

 days later. 



5. Dig down in low ground to see if you can locate the water 

 table. 



6. Partly fill a flowerpot with earth mixed with a spoonful 

 of salt, and set the flowerpot over a vessel that will catch the 

 drainage. Pour water on the soil and evaporate the water that 

 drains through. What became of some of the salt that was in the 

 earth ? How might a field be freed from alkali ? 



References 



"Management of Soil to Conserve Moisture." Farmers' Bulletin 266. 

 "Tile Drainage on the Farm." Farmers' Bulletin 524. 



