Field capacity consist of :

Options

A. capillary water
B. Gravitational water
C. Hygroscopic water
D. Both (a) and (c)

Answer

**Step-by-Step Solution:**

1. **Understanding Field Capacity**: Field capacity refers to the amount of soil moisture or water content that remains in the soil after excess water has drained away and the rate of downward movement has decreased. It is an important concept in soil science and agriculture.

2. **Identifying Components of Field Capacity**:
- **Capillary Water**: This is the water that remains in the soil after gravitational water has drained away. It is held in the soil pores against the force of gravity and is available for plants to use. Capillary water is a significant component of field capacity.
- **Gravitational Water**: This type of water drains out of the soil due to gravity and does not contribute to field capacity. It is the excess water that moves downward through the soil profile and is not retained.
- **Hygroscopic Water**: This is the water that forms a thin film around soil particles and is not available for plant use. It is tightly bound to the soil particles and does not contribute to field capacity.

3. **Conclusion**: Based on the definitions and roles of these types of water in the soil, the components that make up field capacity are:
- **Capillary Water**: Yes, it is a main constituent of field capacity.
- **Gravitational Water**: No, it drains out and does not contribute to field capacity.
- **Hygroscopic Water**: No, it is not available for plants and does not contribute to field capacity.

4. **Final Answer**: Therefore, field capacity consists of **Capillary Water**.