The Arizona sentinel., 1906-03-21
LANDS AND SOILS.

luC EblJuS Ol iLllSb OOunOt SOibl loN fhe river bottoms and valleys and the uplands or mesas. The bottom land: are moister and slightly more fertile if, indeed, it is possible to make com parisons where all are so wonderfully productive and prolific. The uplands or mesas are warmer and perhaps slightly better for the cultivation ot inc citrus fruits. Yuma contains Va riety of soil. The valley lands of the Gila and Colorado rivers have for the most part deep sedimcntary soil oi brownish gray sandy lOam, resting, in most places, upon gray, clay sub-soil at a depth of from ten to twenty feet below the surface. The clay sub-seil forms a hard-pan which is imperEious to water. These soils have been slow ly formed by the decomposition of Ahales, sandstoneS, mails, limestones, etc, mixed with organic and vegetable matter, washed down by the mighty rivers, and have been gradually deposited during the course of centu- ries. The fertiliZing hrOwnish mud held in the water of the Colorado and Gila rivers resembles that of the Nile, and its quantity varies from O. to 0.5 per cent, though the water when even considerably discolored by mud is good to drink, resembling in this respect the Missouri river water. A chemical analysis of the sediments of the Cobra do and the Nile exhibits a wonderful similarity in the constituent parts of each: that of the Colorado exhibiting a trife less potassa, more phosphoric acid and carbonate of lime, the latter being due to the great limstone beds through which the Colorado passes. In other respects tAe sediment of the Colorado is almost identical with that of the Nile. It will be noticed, therefore, that when this water is used for irriga- tion it is superior to artesian water, since it is constantly supplying the land with the richest fertilizing ele- ments. The soil of the valleys is ex- tremely rich in decOmposed vegetable matter and uncombined carbon. readily absorbing the aerial gases, such, espe- cially, as oxygen, which, entering the soil, decowposes the organic matters so that they can be taken up and nour- ish the plan It's, which may be considered leading feature in its fertility. It also readily takes up and retains mOis- ture, while,the firnness of its particles affords every facility for perceiation and capillary action. In its mechan- iral composition its particles are in a state of very fine division, which rem ders it more productive than coarser soils. It acquires heat readily in the daytime, and the loss Of heat at night Is very gradual, so that 1t remains al- ways warm, and is not subject te sud- den changes of heat and cold. Besides it's essential constituents of wager, or ganic or vegetable matter, sand ard
 
 lime, soda, maguesia, iron, ammonia and available forms of nitrogen, phos- phoric acid and potash enter into its composition in the proportions best adapted to add. to its fertility, though sf course, as is always the case in soil analysis, it's composition varies in diff ferent localities and is not always con- stant.
 The soil of the uplands or mesas is lighter and more gravclly, and in some places of free, loamy, calcareous char acter. The mesa lands are warm and generous. They seem especially adapt ed for the grape, olive and citrus fruits generally. Their soil contains more magnesia. lime or chalk than the bot tom lands. It never cracks, and re- tains moisture admirably in summer. It is of that character which will pro- duce g. wine that will keep good for fifty or hundred years and improve annually, not being liable to sour, or, on exposure to the air after one year old, Lo become turbid and change color in the bottle or glass.
 We can safely say that the soil os Yuma county can nowhere be surpassed containing as it does all the essential elements of richness and fertility.