The Arizona sentinel., 1897-02-27

of the Gila and Colorado rivers have for the most part deep seiimentary soil of brownish, gray sandy 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 impervious to water. These soils have been slowly formed by the decomposition of shales, sand>tones, maIis. Emestones, 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 tlof the Colorado and Gila rivers resembles that from the Nile, and its quantity varies from o. to O5 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 wonderful similarity in the constituent parts of each. That of the Colorado exhibiting a trihe less potassa, most phosphOric acid and car bonade of limestone beds through which the Colo rado pass"s 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 artesian waters since it is constantly supplying the land with the richestertilizng elements. The soil of the valleys is extremely rich in dedompOsed vegetable matter and uncombined carbon, readily absorbing the aerial gases, such especially, as oxygen, which en- tering the soil, decomposes the organic matters so that they can be taken up and nourish the plants which may De considered a leading featur, in its fertility. It also readily takes up and retains moisture while the rmness of its particles affords every facility for percoation and the activity of capillary action. In it's mechanical composition it's particles in a state of very fine division which renders it more productive than coarser soils It acquires heat readily in the daytime, and the loss of the heat at night is very gradual, that it mains always warm and is not subject to sudden changes of heat and cold Besides it's essential con stituents of water, organic or vegetable matter sand and clay, chemical analysis shows that lime soda, magpesia, iron, ammonia and available forms of nitrogen, phosphoric acid and potash enter into composition in the proportions best adapted to add to its fertility, though, of course is alway the case in soil analysis its composition varies in different localities and is not always constant.
 The soi o the uplands or mesaS, lighter and more gravelly and in some places of lree, loamy, caleareous character. The mesa lands 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 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 year old, to become turbid and change color in tho bottle or glass.
 We safely say that the soil of Yuma County nowhere be surpassed, containing as it does all the essential elements of richness and fertility.