Elementary principles of agriculture : a text book for the common schools elementaryprinci02ferg Year: 1913 Soils and Soil Management 61 94b. Rate of Cooling of Dry Soils. The same boxes used in H 93a may be used. Note readings when placed in sunlight at 8, 10, and 12. Then put in shade and note the temperature at 2, 4, and 6. Which kind of soil ci oled quickest? What soils retained the'r heat longer? Do the soils that warm quickly cool quickly? What soils would you class as 'warm soils?' 94c. Absorption of Heat by Moist Soils, Use same boxes of soils as above, but add same amount of water t
Elementary principles of agriculture : a text book for the common schools elementaryprinci02ferg Year: 1913 Soils and Soil Management 61 94b. Rate of Cooling of Dry Soils. The same boxes used in H 93a may be used. Note readings when placed in sunlight at 8, 10, and 12. Then put in shade and note the temperature at 2, 4, and 6. Which kind of soil ci oled quickest? What soils retained the'r heat longer? Do the soils that warm quickly cool quickly? What soils would you class as 'warm soils?' 94c. Absorption of Heat by Moist Soils, Use same boxes of soils as above, but add same amount of water to each, and make readings when exposed to sunlight from 8 until 4. The cans or boxes should be weighed at the beginning, and, when through with the test in this experiment, weighed again for results in H 95a, noting loss of weight in each. 94d. Loss of Heat by Moist Soils. As above in H 94b. The same boxes may be used. 95. Soil Mulch. The rain falling on the surface causes the many fine lumps of soil to crumble and run together, and leaves the surface covered by a closely compacted layer or crust. This condition of the soil is very favorable for the rapid evaporation of the capillary water. When the surface becomes dry, the water below will move rapidly to the surface and the soil will soon become dry. The thrifty farmer destroys this crust just as soon as the surface layer can be harrowed or plowed. He thus destroys the close capillary connection formed between the surface and sub-surface soil. The soil mulch should be two or three inches thick. (Fig. 36.) Fig. 36. How cultiv^ation retards surface evaporation. The position of ground water after fifty-nine days, and the per cent of water in the soil at diilerent depths. The shaded plots were cultivated. After King. University of Wisconsin.
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