Fire reduces soil fertility through

Options

A. Volatilisation of plant nuterients
B. Interruption of biogeochemical cycles
C. Formation of ash
D. Both A and B.

Answer

### Step-by-Step Solution:

1. **Understanding Soil Fertility**: Soil fertility refers to the ability of soil to provide essential nutrients to plants. It is influenced by various factors including the presence of nutrients, organic matter, and biological activity.

2. **Impact of Fire on Soil**: When a fire occurs, it can have several effects on the soil, primarily leading to a reduction in its fertility.

3. **Volatilization of Plant Nutrients**: One major effect of fire is the volatilization of plant nutrients. High temperatures from the fire can cause certain nutrients, such as nitrogen and sulfur, to evaporate into the atmosphere. This results in a deficiency of these essential nutrients in the soil, thus reducing its fertility.

4. **Interruption of Biogeochemical Cycles**: Fires can also disrupt biogeochemical cycles, which are natural processes that recycle nutrients in the environment. For example, the nitrogen cycle and carbon cycle can be interrupted by the destruction of vegetation and the soil structure, leading to a further decline in soil fertility.

5. **Conclusion**: Based on the effects discussed, fire reduces soil fertility through both the volatilization of plant nutrients and the interruption of biogeochemical cycles. Therefore, the correct answer to the question is option D: both A and B.