. Productive soils; the fundamentals of successful soil management and profitable crop production. Soils. ALKALI SOILS 43 Wliat Becomes of the Materials Carried Into the Sea.—The sand settles out near the shore, and in time becomes sandstone (Fig. 17). The clay settles to the bottom farther out and finally turns to shale. The saltfe remaining in solution become the "salt of the sea/' Shells.—The carbonate of lime is taken out of solution in the ocean water by myriads of tiny shell animals, whose shells sink to the ocean floor when they die. Coral animals, certain water plants and bacteria
. Productive soils; the fundamentals of successful soil management and profitable crop production. Soils. ALKALI SOILS 43 Wliat Becomes of the Materials Carried Into the Sea.—The sand settles out near the shore, and in time becomes sandstone (Fig. 17). The clay settles to the bottom farther out and finally turns to shale. The saltfe remaining in solution become the "salt of the sea/' Shells.—The carbonate of lime is taken out of solution in the ocean water by myriads of tiny shell animals, whose shells sink to the ocean floor when they die. Coral animals, certain water plants and bacteria also cause carbonate of lime to be deposited. Usually, however, on the sea bottom beyond the accumulations. Fig 17 —The ocean receives all the materials washed from the continents The sand settles out of the river waters near shore, and the clay is carried farther out The salts make the sea-water salty The dissolved carbonate of lime is taken out of solution by tiny shell animals. of sand and mud there are deposited shells and particles of carbon- ate of Hme which in time turn into limestone. As a general rule, whenever limestone, sandstone or shale is found, there at one time existed a sea or lake. The mud and sand, which are the impurities of limestone, con- stitute the soil-forming material when limestone weathers. Alkali Soils.—Soils in regions of little or no rainfall are not leached as they are in humid ot sub-humid climates. The salts formed through weathering processes, therefore, accumulate in these soils. In places the soils are so salty that cultivated plants cannot grow in them (Fig. 18). Such soils are called "alkali ; Salty crusts commonly form on their surfaces. When. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Weir, Wilbert Walter, 1882-. Philadelphia London, J. B
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectsoils, bookyear1920
