Robinson, W. O. (William Orrin), b. 1884, McCaughey, W. J. (William John), 1882-1962, United States. Dept. of Agriculture, United States. Bureau of Soils, United States. Government Printing Office · Washington : Govt. Print. Off. · leaf 10
n equilateral triangle, then the color of practically all soils is determined (approximately at least) by some point in the triangle. a Whitish or gray soils are not generally of much agricultural value for general field crops, though sometimes of very great value for special purposes. In humid… … Black Brownish Red yellow soil is rather rare. Fig. 1.— Diagram showing relation of soil colors. It is generally considered that they owe their color to small amounts of ferric oxide, more or less hydrated. Black soils are universally esteemed highly. They are characterized b}^ a high percentage of…
Soils Color · Soils Composition
Internet Archive · U.S. Department of Agriculture, National Agricultural Library · Public domain (published before 1931). Free to use for anything.
