TABLE OF CONTENTS xi 



CHAPTER XII 



paqss 



The Water of the Soil in its Relation to Plants . 243-263 

 Relations of water to the plant, 167 — The water 

 requirement of plants, 168 — Factors affecting trans- 

 piration, 169 — Effect of crop and climate on transpira- 

 tion, 170 — Effect of soil moisture on transpiration, 171 

 — Influence of fertility on transpiration, 172 — Effect of 

 texture on transpiration, 173 — Actual amounts of water 

 necessary to mature a crop, 174 — Role of capillarity in 

 the supplying of the plant with water, 175 — Influence 

 of water on the plant, 176 — Availability of the water in 

 the soil, 177 — Unavailable soil water, 178 — The wilting 

 coefficient of plants, 179 — Determination of the wilting 

 point, 180 — Calculation of the wilting point, 181 — Re- 

 lation of texture to the wilting point, 182 — Available 

 and superavailable water, 183 — Optimum moisture for 

 plant growth, 184. 



CHAPTER XIII 



The Control of Soil Moisture 264-288 



Run-off losses, 185 — Percolation losses, 186 — Methods 

 of checking loss by run-off and leaching, 187 — Evapo- 

 ration losses, 188 — Methods of checking evaporation 

 losses, 189 — Mulches for moisture control, 190 — Kinds 

 of mulches, 191 — The functions of a mulch, 192 — The 

 soil mulch versus the dust mulch, 193 — Formation of a 

 mulch, 194 — Depth of a mulch, 195 — Resume" of mulch 

 control, 196 — Water saved by a mulch, 197 — Effect of 

 mulehes other than on moisture, 198 — General useful- 

 ness of a mulch, 199 — Other practices affecting evapo- 

 ration losses, 200 — Fall and early spring plowing, 201 — 

 Rolling, 202 — Shelters, 203 — Level cultivation, 204 — 

 Plants, 205 — Summary of moisture control, 206. 



CHAPTER XIV 



Soil Heat 289-326 



Relation of heat to germination and growth, 207 — 

 Chemical and physical changes due to heat, 208 — 



