SCIENCE
EARTH SCIENCE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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It contains all the darker colored minerals
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It contains volcanic rock
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It contains more organic matter
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It contains bits of burned trees
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Detailed explanation-1: -The topsoil is usually darker than lower layers (or horizons) because this is where organic matter accumulates. Soil colour is usually due to 3 main pigments: black-from organic matter. red-from iron and aluminium oxides.
Detailed explanation-2: -Top soil is dark in colour due to the presence of humus and dead and decaying organic matter.
Detailed explanation-3: -Topsoil is the upper layer of soil. It has the highest concentration of organic matter and microorganisms and is where most of the Earth’s biological soil activity occurs.
Detailed explanation-4: -Dark black or brown surface soils with a low value on the Munsell color chart indicate organic matter enrichment. The dark color results from the decomposition of organic matter and the formation of humus, which is black or dark brown in color.
Detailed explanation-5: -This layer is also called the humus layer, which consists of rich decomposed material and organic matter. That’s why the topsoil has a dark brown colour. The humus makes the topsoil soft and porous to hold enough air and water. This is the layer where seeds germinate and roots of the plants grow.