ILLUSTRATIONS 



PAGE 



Three-year-old Washington Xavel orange on the N'uma Mesa Frontispiece 



Cieneral view on the Yuma Mesa 226 



Windbreak of evergreen tamarisk on the Yuma ]\Iesa, 18 months 



from planting 228 



Windbreak of Eucalyptus on the Blaisdell citrus orchard, 26 vears 



old " .... 232 



Castor beans used as a temporary windbreak in a young citrus 



orchard on the Yuma Mesa 232 



Alfalfa used as a cover crop in the Blaisdell citrus orchard 240 



Cover crop of cowpeas planted in rows in Hill's citrus orchard on 



the Yuma Mesa 240 



View in ten-acre block of Valencia oranges in the Blaisdell orchard 



on tlic Yuma Mesa •. . .246 



Individual lemon tree on the Yuma Mesa 248 



Individual Marsh grapefruit tree on the Yuma Mesa 248 



Citrus orchard of George M. Hill on the Yuma Mesa, 8 months from 



planting 249 



The same orchard as shown in Fig. 11, one year later 250 



The same orchard as shown in Fig. 11, two years later 250 



Washington Navel orange produced on the Yuma Mesa 252 



Valencia orange produced on the Yuma Mesa 252 



Grapefruit produced on the Yuma Mesa 256 



Lisbon lemon produced on the Yuma Mesa 256 



Two-year-old grape vine on the Yuma Mesa 258 



Three-acre fig orchard on the Yuma Mesa 259 



Cotton on the Yuma Mesa on land under second vear's cultivation. . .262 



CONTENTS 



PAGE 



General information 225 



Topography of the Yuma Mesa 226 



Climate of the Yuma Mesa 227 



Soil of the Yuma Mesa 234 



Chemical composition of the Yuma sand 235 



Fertilitv of the Yuma sand 239 



Alkali 241 



Physical characters of the Yuma Mesa sand 242 



Fruit crops on the Yuma Mesa 246 



First citrus plantings 246 



Recent citrus plantings 247 



Insect and plant disease problems on the Mesa 249 



Characteristics of fruit grown on Yuma Mesa 249 



General adaptation of varieties of citrus to the Yuma Mesa 254 



Oranges 254 



Grapefruit 255 



Lemons 255 



Other fruits adapted to the Mesa 257 



Dates 257 



Olives 258 



Grapes 258 



Figs 259 



Truck crops 260 



Field crops on the Yuma Mesa 261 



Summary 263 



