QUESTIONS 125 



these would be available first in the soil, and which would remain longest 

 without being leached out? 



16. Effects of Fertilizers. Make pot trials with different fertilizers as 

 suggested in this chapter. This work may be done either on farms or nearby 

 places, or in the home gardens and farms of students, if not at the school itself. 



QUESTIONS 



1. Explain what is meant by the problem of soil maintenance. 



2. What are the chief features of soil improvement? 



3. What are the ways by which tillage may improve soils? 



4. What are the chemical changes wrought by good tillage? 



5. What are the physical changes? 



6. Explain the different lines of improvement due to green manuring. 



7. In what ways do live stock aid in soil maintenance and soil improvement? 



8. Give directions regarding the care of manure. 



9. Explain the use of rock phosphate as a preservative in manure. 



10. Compare the different kinds of litter for use in stables. 



11. What is the use of a covered barnyard, so far as manure is concerned? 



12. Describe how to make a compost for garden use. 



13. Enumerate the benefits from liming of soils. 



14. Explain why green manuring and liming should be combined in farm practice . 



15. What are the different forms of lime? Which ones of these forms are 



cheapest in your locality? Give approximate prices for each form. 



16. What are the comparative weights of the different forms of lime? Which 



form has the most calcium in a ton? 



17. Describe how to handle freshly burned lime in applying it to a field with- 



out injuring the soil or plants. 



18. To what extent are hard wood ashes valuable in the liming of soils? 



19. Give directions to aid in choosing the kind of lime to be applied to a cer- 



tain farm. 



20. What are some of the common rates of application? 



21. What are the three essential elements in commercial fertilizers? 



22. What is the advantage of state inspection of commercial fertilizers? 



23. Give some of the sources from which nitrogen is obtained by fertilizer 



companies. Discuss the relative values of these. 



24. How is calcium cyanamid made, and what valuable ingredients does it 



contain? 



25. State the difference between phosphoric acid and rock phosphates. 



26. Which of these is more permanent and which is most active? 



27. Give methods of determining how much fertilizer to use on a certain field. 



28. Give the advantages of home mixing of fertilizers. 



29. Take a fertilizer tag which gives the analysis of the mixture and reduce 



the statement to its simplest form. 



References. United States Farmer Bulletins: 44, Commercial Fertilizers; 

 77, The Liming of Soils; 88, Alkali Lands; 192, Barnyard Manure; 222, 

 Home Mixing of Fertilizers; 245, Renovation of Worn-out Soils; 257, Soil 

 Fertility; 259, Uses of Commercial Fertilizers; 278, Leguminous Crops for 

 Green Manuring; 326, Building up a Run-down Cotton Plantation; 327, 

 The Conservation of Natural Resources; 342, Conservation of Soil Resources; 

 398, Farm Practice in the Use of Commercial Fertilizers ; 406, Soil Conserva- 

 tion; 421, Control of Blowing Soils; 446, The Choice of Crops for Alkali Land. 



Introduction to the Principles of Soil Fertility, Cornell Reading-Courses, 

 Soil Series No. 1 revised. The maintenance of Fertility, Ohio Exp. Sta., Buls. 

 182, 183. The Fertility of the Land, Roberts. Improving Acid Soils, N. J. 

 Exp. Sta. Circ. 54. Crops and Methods for Soil Improvement, Agee, The Mac- 

 millan Co., N. Y. 



