TABLE OF CONTENTS 



124 Addition of organic matter, 125 Action of plant 

 roots and animals, 126 Addition of lime, 127 Til- 

 lage, 128 The action of the plow, 129 Resume^ 130. 



CHAPTER XI 

 FORMS OF SOIL WATER AND THEIR MOVEMENT . . 



Methods of expressing soil moisture, 131 Kinds of 

 water in the soil, 132 Hygroscopic water, 133 Effects 

 of texture and humus on hygroscopicity, 134 Nature 

 of the film, 135 Effect of humidity and temperature 

 on hygroscopic water, 136 Determination of hygro- 

 scopicity, 137 Heat of condensation, 138 Capillary 

 water, 139 Surface tension and the force developed 

 thereby, 140 The form of water surfaces between soil 

 particles, 141 Factors affecting capillary water, 142 

 Surface tension and the amount of capillary water, 143 



Texture and the amount of capillary water, 144 

 Effect of structure on the amount of capillary moisture, 

 145 Organic matter and the amount of capillary mois- 

 ture, 146 Determination of capillary water, 147 The 

 moisture equivalent of soils, 148 The maximum re- 

 tentive power of soils, 149 Capillary Movement, 150 



Factors affecting rate and height of Capillary move- 

 ment, 151 Effect of thickness of film on capillary 

 movement, 152 Surface tension and capillary move- 

 ment, 153 Effect of texture on capillary movement, 

 154 Texture and capillary pull of soils, 155 Effect 

 of structure on capillary movement, 156 Gravitational 

 water, 157 Pressure and the movement of gravity 

 water, 158 Effect of temperature on the flow of grav- 

 ity water, 159 Effect of texture and structure on the 

 flow of gravity water, 160 Determination of the quan- 

 tity of free water that a soil will hold, 161 The calcu- 

 lation of the free water of a soil, 162 Value of studying 

 flow and composition of gravitational water, 163 The 

 study of gravity water by means of tile drains, 164 

 The lysimeter method of studying gravitational water, 

 165 Thermal movement of water, 166. 



198-242 



