174 SOIL PHYSICS AND MANAGEMENT 



25. What portions are affected by leaching? 



26. What was determined in regard to loss from manure by the Ohio 



Station ? 



27. What is the best way to keep manure to prevent loss? 



28. What are absorbents ? Name some. 



29. What are the uses of reenforcing materials ? 



30. Upon what does the value of manure depend? 



31. How may its real value be determined? Upon what does this depend? 



32. On what kind of soil should manure be applied ? 



33. What crops respond best to manure? 



34. What amounts of manure are test to apply? 



35. Give the results obtained by the Purdue Station. 



36. What are the advantages to be gained by the use of the manure 



spreader ? 

 37'. W r hat is the value of corn stalks and straw ? 



38. What increases have been obtained by the use of crop residues? 



39. What is the advantage of growing non-tilled crops? 



40. What is essential in a rotation for soil improvement? 



41. How should the legume be managed? 



42. Which legumes are best for soil improvement ? 



43. What was the total amount of organic matter produced by a single 



season's growth of sweet clover? 



REFERENCES 



1 Hopkins, C. G., Soil Fertility and Permanent Agriculture, 1910, p. 201. 

 1 Beavers, J. C., Circular 49, Purdue Station, Farm Manures, 1915, p. 3. 



* Van Slyke, L. L., Fertilizers and Soils, 1915, p. 291. 

 4 Op. Cit., p. 291. 



Ontario Station. 



Thome, C. E., Farm Manures, 1914, p. 148. 



7 Circular 49, Purdue Station, p. 14. 



Hopkins, C. G., Soil Fertility and Permanent Agriculture, 1910, p. 220. 



