LIST OF ILLUSTRATIONS xv 



FIGURES PAGE 



27. Curves showing the maximum soil temperatures under the dif- 



ferent soil treatments in an orchard. (After Woodbury, 

 Noyes and Oskamp, Ind. Agr. Exp. Sta. Bull. 205) 158 



28. Curves showing the relative formation of nitrates under sod, 



tillage, and tillage cover-crop systems of orcharding. Parts 

 per million dry soil 161 



29. Row of trees to left was fertilized with 5 pounds nitrate of soda 



to each tree. The one to right untreated 200 



30. Apple tree injured by hail storm. Note abrasions of bark and 



partial defoliation 225 



31. Length of growing season in different parts of the United States. 



(After Henry) 229 



32. Isophanal map of North America. (After Hopkins) 236 



33. Map showing the boundaries of the Michigan fruit-belt. 



(After Seeley) 241 



34. Fruit-bud of sour cherry. Left, flower bud alive; right, flower- 



bud killed 255 



35. Winter injury on trunk of a Baldwin apple tree 256 



36. Diagram of a simple pistil as seen in lengthwise section, show- 



ing a single ovule just prior to fertilization. (From Robbins' 

 Botany of Crop Plants, by permission of P. Blakiston's Sons 

 Co.) 290 



37. French crab, imported apple seedling. (From Bailey, The Nur- 



sery Manual, by permission Macmillan Co.) 341 



38. The tongue or whip-graft of apple 352 



39. Shield-budding. (From Bailey, The Nursery Manual, by per- 



mission Macmillan Co.) 353 



40. Method of double-working the apple 354 



