78 PHYSIOLOGICAL PROCESSES IN PLANTS 



Questions 



1. Why should a farmer cultivate or till the soil ? 



2. What is the purpose of mulching the soil ? 



3. How deep has the mesquite or sagebush been known to 

 send its roots after moisture ? Where does it grow ? 



4. What harm would likely result to trees if the paving and 

 sidewalks should be built up closely about them ? 



5. Would potted plants be likely to thrive well if the hole 

 in the bottom of the pot was kept plugged up? Explain. 



6. Explain the truth of the following : " Perfect agriculture 

 is the true foundation of trade and industry, it is the foun- 

 dation of the riches of states." 



References 



Hunter, Essentials of Biology. Chap. VII. 



Coulter, Barnes, and Cowles, A Textbook of Botany. Vol. I, pp. 302- 

 317. 



Wilkinson, J. W., Practical Agriculture. 



Bailey, "Going back to the Old Farm. 1 ' Country Life in America, 

 September, 1904. 



Bailey, " New Ideals in the Improvement of Plants." Country Life in 

 America, July, 1903. 



Marcusson, " Exploring for New American Crops." World's Work, 

 September, 1906, December, 1909. 



Brannon, " Higher Education and the Farm." Educational Review, 

 December, 1909. 



: Collingwood, H. W., "Back to the Land." Metropolitan Magazine, 

 June, 1910. 



Burroughs, " Making a Living from the Soil." Colliers, May 14, 1910. 



PROBLEM XV 



A. study of some of the relations between roots and 



the soil. 



a. Origin of Soil 



1. MINERAL MATTER 



Method. Put some iron tacks in enough water to cover 

 about half of them. Set aside then and observe them for a 

 few days. 



