250 



INDEX 



Bacteria, in relation to air supply, 128. 



in relation to lime, 189. 



in relation to moisture, 128. 



in relation to organic matter, 129. 



in relation to soil acidity, 129. 



in relation to soil fertility, 129. 



in relation to temperature, 129. 



nitrification caused by, 132. 



numbers in soils, 127. 

 Basic slag, 172. 



Calcite, plant-food material in, 7. 

 Capillary capacity, test for, 87. 

 Capillary movement, test for, 86. 

 Capillary water, 63. 

 Carbon dioxide, conditions that affect 

 quantity, 146. 



demonstration of formation in soil, 

 154. 



demonstration of presence in soil, 

 153. 



functions in soil, 147. 



percentage in bare and planted 

 soil, 106. 



percentage in soil air, 145. 



production by microorganisms, 107. 



production in soils, 145. 

 Chemical analysis of soil, 98. 

 Chemical composition, of various 

 soils, 91. 



relation to productiveness, 93. 

 Class, the soil, defined, 33. 



in soil survey, 44. 



method for determination, 34. 

 Classification of soils in survey, 43. 

 Colluvial soils, described, 22. 



formation of, 22. 

 Compaction of soil due to root 



growth, 2. 

 Compost, building of a pile, 234. 

 Crop rotation, 242. 

 Crops, relation to soil texture, 32. 

 Cumulose soils, composition of, 21. 



described, 20. 



formation of, 20. 

 Cyanamid, changes in the soil, 162. 



composition of, 161. 



manufacture of, 161. 



Denitrification, 135. 



Dolomite, plant-food materials in, 7. 



Drainage, and length of growing 

 season, 80. 



and available water, 79. 



benefits from, 78. 



by open ditches, 80. * 



defined, 78. 



in relation to soil air, 79. 



in relation to tilth, 79. 

 Drainage water, composition of, 



103, 104. 

 Drains, arrangement of, 82. 



concrete, 81. 



tile, 81. 



Evaporation, prevention of, 74-77. 

 proportion of rainfall lost by, 73. 



Feldspars, plant-food materials in, 7. 

 Fertility of soil in relation to bac- 

 teria, 129. 

 Fertilizer constituents, trade values, 

 200. 



experiments, plan for, 212. 



formulas for different crops, 210. 



ingredients, how to mix, 205. 



mixture, calculation of, 204. 

 Fertilizers, brands of, 196. 



computation of wholesale value, 

 202. 



conditions that influence effect of, 

 217. 



consumption of, in U. S., 196. 



cumulative need of, 218. 



effect on soil acidity, 114. 



for different crops, 207. 



for different soils, 211. 



for grasses, 208. 



for leguminous crops, 208. 



for orchards, 209. 



for root crops, 209. 



for small grains, 207. 



for vegetables, 209. 



high and low grade, 198, 



home mixing of, 203. 



inspection and control, 199. 



law of diminishing returns, 215. 



methods of applying, 214. 



nitrogenous, 155. 



nitrogenous, forms of nitrogen in, 

 157. 



phosphoric acid, 171. 



