The Arizona sentinel., 1897-01-30

of the Gila and Colorado rivers have for the most parta deep sedimentary soil of brownish, gray san1y loam, resting, in most places, upon gray clay subsoil at a depth of from tento twenty feet below the surface, The clay subsoil forms a hard pan which is imperyious to water These soils have been slowly formed by the decomposition of shales, sandstoncS, mars. limestones, etc. mixed with or5 g1nic and vegetable matter, washed down by the mighty rivers and have been gradually deposited curing the course of centy,rics The fertilizng brownish mud held ill the wat tlof the Colorado and Gila rivers rescrTbles 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 pect the Missouri river water. chemical analysis of the sediments of the Colorado and of the Nile exhibits wonderful similarity iH the constituent parts of each. That of the Colorado exhibiting triie 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 wate- is used for irrigation it is superior to artesg waters since it is constantly supplying the land with the richestfertilizing clements. ThesC 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, dccomposes the organic matters so that teey Gan be taken up and nourish the plants which may be considered leading feature in its fertility. It also readily takes up and reteins moisture, while the rmness of it's particles affords every facility for percolation and the activity of capillary action. In ts mechanical composition it's particles are in a state of very fine division which renders it more productive than coarser soils It acqurieS heat readily in the daytime and the loss of the heat at night is very gradual, that it re- mains always warm and is not subject to sudden changes of heat and cold Besides its essential con- stituents of water, organic or vegetable matter, sand and clay, chemical analysis shows that lime, soda, magnesia, iron, ammonia and available forms of nitrogen phosphoric'ecid and potash enter into composition fn the proportions best adapted to ada dsts fertility, though, of course, is always 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 ,ree, 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 msgnesia, Eme 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 turbid and change color in the bottle or glass.
 We can safely say that the soil of Yuma County can nowhere be surpassed, containing it does all the essential elements of richness and fertility.