CONTENTS 



CHAPTER XXI 



PAGES 



TILLAGE 220-229 



Desirable physical condition of the soil .... 220 



The breaking-plow 221 



Types of plows 221 



Subsoiling 223 



Time of plowing . . . . * . . . . 223 



Method of plowing 224 



The disk harrow ........ 225 



Cultivation of plants 227 



Controlling root-growth ....... 227 



Elimination of competition 228 



Length of cultivation 229 



CHAPTER XXII 



CONTROL OF SOIL MOISTUBE 230-236 



Value of water in the soil 230 



The soil a reservoir . . . . . . . . 231 



The land-roller 232 



The plank-drag 233 



The mulch 233 



Mulches of foreign material 234 



Plowing straw down 235 



The summer-fallow 235 



The modern fallow . 236 



CHAPTER XXIII 



DRAINAGE 237-246 



Underdrainage 237 



Counting the cost . . . . . . . .238 



Where returns are largest 239 



[xiii] 



