Humus decomposition retards with

Options

A. High oxygen
B. High lignin
C. High temperature
D. High nitrogen

Answer

To solve the question "Humus decomposition retards with," we will analyze the options provided and determine which factor slows down the decomposition of humus.

### Step-by-Step Solution:

1. **Understanding Humus**:
- Humus is the organic component of soil formed by the decomposition of dead and decaying parts of plants and animals. It plays a crucial role in soil fertility and structure.

2. **Identifying Decomposition Factors**:
- The decomposition of humus is influenced by various environmental factors, including the presence of oxygen, temperature, nitrogen, and certain compounds like lignin.

3. **Analyzing the Options**:
- **Option 1: High Oxygen**: Oxygen is essential for the decomposition process as it supports aerobic microorganisms. High oxygen levels would actually enhance decomposition, not retard it.
- **Option 2: High Lignin**: Lignin is a complex organic polymer found in the cell walls of plants. It is resistant to decomposition, and high concentrations of lignin in humus would slow down the decomposition process.
- **Option 3: High Temperature**: Generally, higher temperatures can increase the rate of decomposition by enhancing microbial activity, so this would not retard decomposition.
- **Option 4: High Nitrogen**: Nitrogen is a vital nutrient for microorganisms involved in decomposition. High nitrogen levels typically promote decomposition rather than hinder it.

4. **Conclusion**:
- Based on the analysis, the correct answer is **Option 2: High Lignin**. High levels of lignin in the soil slow down the decomposition of humus.

### Final Answer:
Humus decomposition retards with **high lignin**.

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