The Arizona sentinel., 1906-06-27
Climate and Soil of the
 Yuma Area.

The Yuma area is in an extremely
 arid belt. The rainfall is not only very | light, but it's time of occurrence is also
 very irregular, so that upon all lands
 irrigation is the only source of moisture
 to be depended upon for all cultivated
 crops. The summers are long and hot,
 while the winters can hardly be called such at all.. The maximum daily tenn
 perature in summer sometimes ranges high, but the nights are usually cool
 and comfortable. The winter nights, especially in the valley, are occasion ally quite cold, ice often forming, but
 the days are most delightful. Very seldom is cloud seen. Many of the
 people live almost entirely out of doors. and suffer very little discomfort on ac- count of tbe weather The mesa land, situated to the south and east of the
 valley lands along the river, has q slightly different climate from these valley lands. Upon this mesa the nights are not so cold and frost occurs less often. Here orange and other cit rus trees thrive and suffer none from cold weather.
 The valley lands immediately along the river are broken only by the local occurrence of sand dunes, gullies, la- goons or old river beds. These minor departures from grade in some instanc- es will make leveling for irrigation quite expensive but in very few in- stances are they sufficient to make eco nOmical leveling impossible. Skirting the valley lands on the east and south is large area of mesa lands which for the most part is comparatively level. This mesa proper rises from 65 to 70 feet as an abrupt bluff along the valley lands. In the eastern part of the area however, there is quite little mesa land that is but few feet higher than the valley.
 The valley is formed almost wholly from sedimentary deposits left by the river as it has cut through the mesa to form the valley. The general formal tioli' is ;s great bed of sand overlaid and inter-stratiied with layers of finer ma terial deposited by the river as it has shifted it's course from one side of the valley to the other. Except immedi- ately along the foothills or mesa that surrounds the valley, the soils are not traceable to the rock from whence they came, as the Colorado has d great num- Der of tributaries which drain vast ries may be chiefly responsible at diff ferent food seasons for the sediment carried by this lower part of the stream. The mesa is an old coastal plain, and that part of it mapped was once near the beach. It is all comparatively level, except for strip about one-fourth of a mile wide along the bluff line, which erosion has made quite rough.
 The area is dissected by the Colorado river, the largest stream in the South west. The Gila river, an intermittent stream, flows into the Colorado at the town of Yuma. Gila valley forms the greater part of the bottom lands of the valley proper.
 The northern part of the area is bounded on each side by granite hills, while farther to the south the eastern side of the mesa land mapped is bound ed by only slight trise in the plain, the soils remaining the same to the east ward. Colorado river, where it forms the boundary between Lower CalifOr- nia and Arizona, bounds the area on the west.
 SOILS.
 The soils of the area are distinctly of two series-valley soils proper, or those | alluvial soils formed from deposits of the Colorado and Gila rivers, and mesa soils, or those which formed the coastal plain along the gulf when it extended much farther inland than at present. The river valleys are underlaid at va rying depths by sand, which makes the drainage in the soil itself very good. This sand is in places quite coarse, but ,he greater part is medium to fine in .exture and has the characteristics of luick@,nd. When this fine sand is .ound on the surface it forms the Impe- ,ial fine sandy loam.
 The mesa is made up almost entirely ,f one type of soil, a rather coarse sand, hat in places is cemented together oy . small amount of lime. Along the washes in the low mesa land to the east of the northern part of the area is ound very loose, incohereht, gravelly and which was mapped as Fresno yravelly sand.-EXtracts from ''SOil Survey of the Yuma Area" by Bureau If Soils, Dept. of Agriculture
 Early Grapes.