FERTILIZERS. 47 



18. What do you understand by the "physical" condition of soils? 



19. Do all crops grow equally well on all soils? Give reasons. 



20. How much water will a plant take from the soil in producing 

 100 pounds of dry matter, as an approximate average? 



21. What do you understand by the terms, capillary water, water 

 table, percolation? 



22. In what three ways may water be lost from the soil? 



23. Why does shallow cultivation tend to prevent evaporation? 



24. Explain the term "humus". 



25. How is the humus of the soil obtained and what is its general 

 effect on the soil? 



26. Explain the terms "quicklime", "carbonate of lime", and "hy- 

 drated lime". 



Books for Reference. 



1. Fertilizers Vorhees, 8-12 Macmillan Co $1 25 



2. .Soils and Fertilizers Snyder, 8-13 Macmillan Co 1 25 



3. Fertility of the Land Roberts, 8-12 Macmillan Co 1 50 



4. Soils Lyon & Fippin, 8-12 Macmillan Co 1 75 



5. First Principles of Soil Fertility Vivian, 8-12 Orange Judd 1 00 



6. Fertilizers and Crops Van Slyke, 8-12 Webb Publ Co 2 00 



7. Soils Hilgard, 8-12 Macmillan Co 100 



8. Manures and Fertilizers Wheeler, 8-12 Macmillan Co . . 1 50 



U. S. Bulletins Dept. of Agriculture. 



FARMERS' BULLETINS. 

 Number. 



222. Home Mixing Fertilizers. 

 225. Home Mixing of Fertilizers. 

 44. Commercial Fertilizers. 

 259. Use of Commercial Fertilizers. 







IMPORTANT BULLETINS. 



Circular No. 12 The Purchase and Home-Mixing of Fertilizers, by F. 

 W. Taylor. The New Hampshire Experiment Station, Durham, 

 New Hampshire. 



Extension Bulletin. Formation of the Soil. Ohio State Agricultural 

 College. 



Circular No. 131. Maintenance of Soil Fertility. Ohio Agricultural Ex- 

 periment Station, by Chas. E. Thorne. 



Circular No. 79. By Chas. E. Thorne. Ohio Agricultural Experiment 

 Station, Wooster, Ohio. "How to Determine the Fertilizer require- 

 ments of Ohio Soils". 



Circular No. 165. Shall we Use Complete Commercial Fertilizers in the 

 Corn Belt? by Cyril <G. Hopkins, University of Illinois, Urbana. 111. 



