SOLVED

21) What mineral particles are the dominant coloring agents in reddish, brownish, and yellowish soils? A) soluble potassium and sodium bicarbonates B) humus and calcium carbonate C) very fine-sized, silica and calcite particles D) dust-sized grains of iron oxides 22) Which term best describes an accumulation of angular rock fragments at the base of a steep, bedrock slope or cliff? A) trellis slope B) taliche slope C) tellus slope D) talus slope 23) In which area would weathering by frost wedging probably be most effective? A) in a moist, tropical forest B) in cool high desert areas C) where the subsoil is permanently frozen D) in moist, temperate climates 24) Which one of the following statements concerning soil erosion is not true? A) Sheet erosion, rills, and gullies develop mainly during prolonged droughts. B) Soils form naturally by weathering; if protected from erosion, sound management can maintain or enhance their nutrient levels and textural characteristics. C) Rates of soil erosion exceed rates of soil formation in some parts of the world. D) Grasses and other vegetation, windbreaks, and contour cropping will help reduce losses of soil from cultivated lands. 25) Lateritic soils form under what climatic conditions? A) warm and moist as in a wet, tropical forest B) cool and relatively dry as in the northern Great Plains of the United States C) hot and dry as in the desert regions of North Africa and Arabia D) moist and temperate as in the northeastern United States 26) Which of the following statements concerning humus is not true? A) Humus is typically found above the B soil horizon. B) Humus consists of decaying and partly decayed leaves and other plant materials. C) Humus is readily leached from the B horizon in weakly acidic, soil solutions. D) Humus is less abundant in wet, tropical, forested areas than in temperate, forested areas. 27) Which of the following statements concerning lateritic soils is generally not true? A) They form in warm, moist, tropical climates. B) They are mainly red in color. C) They remain highly productive agriculturally without additions of fertilizers. D) They consist of only the most insoluble, soil-forming minerals. 28) Which of the following best describes the process of eluviation? A) removal of very fine-sized silt and clay particles from the A and E soil horizons B) buildup of calcite in the B-horizon of pedocal soils C) removal of soluble chemical constituents from the A and B soil horizons D) feldspar decomposition and leaching of the soluble products from the C soil horizon 29) From the land surface downward to the unweathered bedrock, which of the following is the correct order of the different soil horizons? A) 0, A, E, B, C, bedrock B) A, B, C, D, E, bedrock C) E, A, B, C, 0, bedrock D) D, E, C, B, A, bedrock