THE ESSENTIALS OF AGRICULTURE 



' Sedentary 



.Transported 



LColluvial 



QUESTIONS AND PROBLEMS 



1. In the classification of soils given below, answer each of the questions 

 asked. 



f Sandstone from what derived ? 



{Residual -I Granite from what derived ? 

 I Limestone from what derived ? 

 C How formed ? 

 Cumulose<j When formed ? 

 I Principal use ? 



SOILS { { How formed ? 



"Alluvial \ Where formed? 



I How distinguished ? 

 T How formed ? 

 Glacial \ Where formed ? 



I When made? 

 ^Eolian J How formed ? 

 Loess |^ Where formed ? 

 f How formed ? 

 ^ Where formed ? 



2. How does rain water assist in forming and in modifying soil and 

 subsoil ? 



3. How does the oxygen of the air aid in soil forming? 



4. How can you distinguish soil from subsoil? Can you make similar 

 distinctions in freshly washed sand or in blown sand? 



5. Where does the mineral matter in soil come from? 



6. What use of the mineral matter is made by the plant ? 



7. What proportion of the soil does mineral matter constitute ? 



8. What is the source of organic matter in soils ? 



9. Is soil carried by air currents? Can you answer this by placing an 

 oiled glass surface so that it is exposed to the air for a few hours? Why 

 use an oiled surface ? 



EXERCISES 



1. Study of soils in the field. Collect samples of limestone, sand- 

 stone, and granite soils. Can you locate soils which came chiefly from 

 each of these kinds of rock ? 



2. Classification of neighboring soils. Make an excursion to the 

 field, and study as many kinds of soil as possible. Study soils in the 

 making, along streams, bluffs, or railroad cuts. Classify the soils 

 examined as to the method of formation, such as residual, cumulose, 



