The Arizona sentinel., 1896-02-01

of the Gia and Colorado rivers have foI the most part deep sedimentary soil of brownish, gray san1y loam, resting, in most places, upon a gray clay subsoil at depth of from ten to twenty feet below the surface, The clay subsoil forms hard pan which is mpervious to water. These soils have been slowly formed by the decomposition of shales, sandstones, marls. limestOnes, etc., mixed with or ganic and vegetable matter, washed down by the mighty rivers and have been gradually deposited during the course of centuries. The fertilizing brownish mud held in the wat tIof the Colorado and Gila rivers resembles that from the Nile, and its quantity varies from O.1 to O.5 per cent, though the water when even considerably discolor ed by mud is good to drink resembling in this res pect the Missouri river water. A chemical analysis of the sediments of the Colorado and of the Nile exhibits a wonderful similarity in the constituent parts of each. That of the Colorado exhibiting triAe less potassa; most phosphoric acid and car bonade of limestone beds through which the Colo rado passrs. In other respects the sediment of the Colorado is almost identical with that of the Nile It will be noticed, therefore, that when this water is used for irrigation it is superior to artesan waters since it is constantly supplying the land with the richestfertilizing elements. The soil of the valleys is extremely rich in dedomposed vegetable matter and uncombined carbon, readily absorbing the aerial gases, such especially, oxygen, which en- tering the soil dccomposes the organic matters so that they can be taken up and nourish the plants which may be considered a leading feature in its fertility It also readily takes up and retains moisture while the irmness of it's particles affords every facility for percoation and the activity of capillary action In ts mechanical composition its r+ic i,, o ctota Of fine division which renders it more productive than coarser soils It acquires heat readily in the daytime, and the loss of the heat at n;ge is very gradual, that it re- mains always warm and is not subject to sudden changes of heat and cold Besides its essential stituents of water, organic or vegetable natter sand and clay, chemical analysis shows that lime soda magnesia, iron, ammonia and available forms of nitrogen phosphoric acid and potash enter into composition in the proportions best adapted to add to it's fertility though of course, as is always the case in soil analysis, its composition varies in different localities and is not always constant.
 The soil of the uplands, or mesas, S lighter and more gravelly and in some places of a free loamy calcareous character. The mesa lands are warm and generous. They seem especially adapted for the grape, olive and citrus fruits generally. Their soil contains more magnesia, lime or chalk than the bottom lands It never cracks and retains moisture admirably in summer It is of that character which will produce wine that will keep good for fifty or hundred years, and improve annually, not being liable to sour, exposure to the air, after one year old, to become turbd and change color in the bottle or glass.
 We safely say that the soil of Yuma County nowhefe be surpassed containing as it does all the essential elements of richness and fertility.