The soil near the surface is usually darker then the soil about one water down. This is because the top soil is

Options

A. Young & wet
B. Richer in organic matter
C. Richer in Ca & Mg
D. Dry

Answer

**Step-by-Step Solution:**

1. **Understanding Soil Layers**: The soil is composed of different layers, with the top layer known as topsoil. This layer is crucial for plant growth and contains various organic and inorganic materials.

2. **Color Variation in Soil**: The question states that the soil near the surface is darker than the soil one meter down. This color difference is primarily due to the composition of the soil layers.

3. **Role of Organic Matter**: The topsoil is rich in organic matter, which includes decomposed plant and animal materials. This organic matter contributes significantly to the soil's color.

4. **Formation of Humus**: Decomposers such as fungi and bacteria break down organic matter into simpler substances. The end product of this decomposition is known as humus, which is a dark, amorphous substance.

5. **Impact of Humus on Soil Color**: Humus is responsible for the dark coloration of the topsoil. It not only gives the soil its dark color but also enhances its nutrient-holding capacity, making it fertile.

6. **Conclusion**: Therefore, the reason the topsoil is darker than the soil one meter down is due to the presence of humus formed from the decomposition of organic matter, which is abundant in the top layer of the soil.

**Final Answer**: The topsoil is darker because it is rich in organic matter, which decomposes to form humus, giving it a dark color.

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