REVIEW QUESTIONS 32Q 



tion ? 60. Explain the terms : sedentary, transported, alluvial, 

 colluvial, volcanic, and wind-formed soils. 61. What is feldspar 

 and what kind of soil does it produce ? 62. Give the general 

 composition of the following rocks and minerals and state the 

 kind of soil which each produces : granite, mica, hornblende, 

 zeolites, kaolin, apatite, and limestone. 



CHAPTER IE 



63. What elements are liable to be the most deficient in soils ? 

 64. Name the acid- and base-forming elements present in soils. 65. 

 What are the elements most essential for crop growth ? 66. State 

 some of the different ways in which the elements present in soils 

 combine. 67. Why is it customary to speak of the oxides of the 

 elements and to deal with them rather than with the elements ? 68. 

 Do the elements exist in the soil in the form of oxides ? 69. What 

 are double silicates ? 70. In what forms does carbon occur in soils ? 

 71. Is the soil carbon the source of the plant carbon ? 72. What 

 can you say regarding the occurrence and importance of the sulphur 

 compounds ? 73. What influence would o.io per cent chlorine have 

 upon the soil ? 74. In what forms does phosphorus occur in 

 soils ? 75. What is the principal form in which nitrogen occurs 

 in soils ? 76. What can be said regarding the hydrogen and 

 oxygen of the soil ? 77. State the principal forms and the value as 

 plant food of the following elements : aluminum, potassium, calcium, 

 sodium, and iron. 78. For plant-food purposes, what three 

 divisions are made of the soil compounds ? 79. Why are the 

 complex silicates of no value as plant food ? 80. Give the relative 

 amounts of plant food in the three classes. 81. How is a soil 

 analysis made ? 82. What can be said regarding the economic 

 value of a soil analysis ? 83. What are some of the important facts 

 to observe in interpreting results of soil analysis ? 84. Under what 

 conditions are the results most valuable ? 85. Do the terms i volatile 

 matter ' and i organic matter ' mean the same ? 86. How may organi c 

 acids be employed in soil analysis ? 87. Why are dilute organic 



