FORESTRY
SOIL SCIENCE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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____ is the upper layer of soil on the surface of Earth that is dark in color and has the smallest particles.
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topsoil
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humus
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subsoil
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None of the above
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Explanation:
Detailed explanation-1: -A HORIZON-This is the layer that we call “topsoil” and it is located just below the O Horizon. This layer is made up of minerals and decomposed organic matter and it is also very dark in color. This is the layer that many plants roots grow in.
Detailed explanation-2: -The uppermost layer that is topsoil is dark because it is rich in humus and minerals.
Detailed explanation-3: -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.
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