Which is not true for humus?

Options

A. Dark colored amorphous substance
B. Highly resistant to microbial action
C. Acts as reservoir of nutrients and increases water holding capacity of soil
D. Degradation product of proteins and fats and produced by the process of mineralization

Answer

### Step-by-Step Solution:

1. **Understanding Humus**:
- Humus is a dark-colored, amorphous substance that results from the partial decomposition of plant and animal matter. It is a crucial component of soil and contributes to its organic content.

2. **Characteristics of Humus**:
- **Dark Colored**: Humus is typically dark brown or black in color.
- **Highly Resistant to Microbial Action**: Humus is known for its resistance to decomposition by microbes, making it stable in the soil.
- **Reservoir of Nutrients**: It serves as a reservoir of essential nutrients for plants.
- **Increases Water Holding Capacity**: Humus improves the soil's ability to retain moisture, thereby enhancing its water holding capacity.

3. **Decomposition Process**:
- Humus is formed through a process called **humification**, which involves the breakdown of organic matter by decomposer organisms.
- While humus itself can be further broken down by microbes, this process is known as **mineralization**, where inorganic nutrients are released.

4. **Evaluating the Options**:
- The question asks which statement is **not true** for humus.
- The options include:
- Dark colored amorphous substance (True)
- Highly resistant to microbial action (True)
- Acts as a reservoir of nutrients (True)
- Increases water holding capacity of soil (True)
- Degradation product of proteins and fats (Not True)
- Produced by the process of mineralization (Not True)

5. **Identifying the Incorrect Statement**:
- The statement "degradation product of proteins and fats" is incorrect because humus is not specifically a degradation product of proteins and fats; it is formed from the decomposition of plant and animal matter.
- The statement "produced by the process of mineralization" is also incorrect because humus is formed through humification, not mineralization.

6. **Conclusion**:
- Therefore, the correct answer to the question "Which is not true for humus?" is "degradation product of proteins and fats" and "produced by the process of mineralization".