VERTICAL FARMING 17 



QUESTIONS 



1. Describe the formation of one type of soil not made from 



rock particles. 



2. Does the action of the air always soften freshly exposed 



rocks ? 



3. Name the forces that have been most effective in forming 



the soils in your vicinity. 



4. By what agencies have your soils been moved? 



5. Is the typical soil of your farm finer or coarser than the 



underlying subsoil ? 



6. Can a mixture of coarse sand and clay* become as tightly 



compacted as a dense clay ? 



7. What, in detail, are the processes in the formation of plow 



sole on your typical soils ? 



8. Why are arid soils less troubled with shortages of plant food 



than humid soils ? 



9. What physical characteristic of your soils lends itself most 



readily to improvement? 



