TABLE OF CONTENTS xiii 



PAGE 



31. Learning How to Spend. John M. Gillette 122 



32. An Efficient Standard of Rural Life. T. N. Carver . . . 124 



III. LAND AND OTHER NATURAL AGENTS OF 



AGRICULTURAL PRODUCTION 

 INTRODUCTION 126 



A. AREA THE FUNDAMENTAL FACT 



33. Some Figures Concerning Land Area 129 



B. THE RELATION OF CLIMATE TO THE PRODUCTIVITY OF LAND 



34. Agriculture's "Farthest North." W . P. Rutter .... 130 



35. The Disadvantage of too Much Heat . . . . . . . 131 



36. Local and Seasonal Peculiarities of Climate 



a) Frosts. Harry J. Wilder 133 



6) A Marginal Climate. Macy H. Lapham ..... 134 



c) Winds. L. E. Hazen ............ 136 



37. Annual Rainfall of the United States. Map 13? 



38. The Possibilities of Irrigation Farming. Carl S. Scofield . 138 



39. Need of Irrigation hi the Humid Region. Milo B. Williams 142 



40. Dry Farming as a Means of Increasing Our Agricultural 

 Product. E. C. Chilcott 146 



41. The Introduction of Dry-Land Plants. A. N. Hume and 

 Manley Champlin *5 X 



42. Drainage as a Means of Reclaiming Land. Samuel H. 

 McCrory 154 



43. Utilizing Plants of High Water Requirements. 0. W. Barrett 157 



C. FERTILITY AS A LIMITING FACTOR IN AGRICULTURAL PRODUCTION 



44. Chemical Content as a Measure of Productive Power. Cyril 



G. Hopkins -. ... 158 



45. Physical Factors Determining the Agricultural Quality of 

 "Land. Edward J. Russell 161 



46. Bacteria and Soil Fertility. P. E. Brown 167 



47. The Real Meaning of Soil Fertility and Soil Exhaustion. 

 Edward J. Russell . i7 2 



D. TOPOGRAPHICAL LIMITATIONS TO AGRICULTURE 



48. Soil Erosion. R. 0. E. Davis 174 



49. Grazing Where Tillage Is Impracticable. James Stephen- 

 son, Jr. 177 



50. Tree Crops for the Hill Lands. /. Russell Smith . . . . 179 



