“THE SOIL ” 155 
4. Name three forms of matter. What is inorganic and 
organic matter? Give examples of each. 
5. Name nine soil builders and tell how each works on rock. 
6. Write out the classes and subclasses of soils according to 
the method of formation. 
7. Why are alluvial soils very fertile? 
8. How are farm soils named? What is humus? 
9. Why will clay soils hold more water than sandy soils? 
Name some plants that do well on clay and sandy soils. 
10. What are heavy and light soils? Explain fully. 
11. Explain the formation of sour or acid soils. How may 
acid soils be improved? 
12. How are alkali soils formed? How may they be improved? 
13. State several ways by which plant food is lost from the soil. 
14. How may our farms lands be made more productive? 
PRACTICAL WORK 
Exercise 1 
Object: A field study of soils in your community. 
Materials Needed: Post-hole digger, yardstick, tapeline, fruit 
jars, stakes, hatchet, notebook. 
Procedure: 1. Lay out an acre tract of land near the school 
and mark it off with four comer stakes. Record the location 
and the measurements of one acre of land. 
2. Take the post-hole digger and begin digging. As, soon as 
the color of the soil changes, record the depth of the soil and 
reasons for its color. Fill one of the fruit jars with a sample 
of the soil. Then continue digging until you have gone from 
two to three feet deep. Note the color of the subsoil. Why is 
it moist? Collect a sample of the subsoil in fruit jar No. 2 to 
be used later in the class room. Repeat this operation, taking 
samples from three other places on the acre tract. Keep the 
jars covered and store them at the school building for future 
study. 
3. Estimate the average depth of the soil on the acre of land 
studied. Why is the soil deeper and different in color in the 
places where samples were collected? 
4. Carefully study the soils and subsoils on several of the best 
farms in your community. Compare the soils and subsoils of 
bottom land with soils and subsoils of hilly lands, 
