1. What is Field Capacity?

Field Capacity (FC) is the amount of water content remaining in the soil after excess water has drained away and the rate of downward movement has decreased. It represents the maximum water holding capacity of soil against gravity.

2. How Does the Calculator Work?

The calculator uses the Field Capacity equation:

Where:

• \( \text{Water Retained} \) — Volume of water retained in soil (m³)
• \( \text{Soil Volume} \) — Total volume of soil sample (m³)

Explanation: The equation calculates the percentage of water that soil can hold after drainage, which is crucial for determining irrigation needs and water management in agriculture.

3. Importance of Field Capacity Calculation

Details: Accurate field capacity calculation is essential for proper irrigation scheduling, water conservation, crop yield optimization, and preventing waterlogging or drought stress in plants.

4. Using the Calculator

Tips: Enter water retained volume in m³, soil volume in m³. Both values must be positive numbers greater than zero. The result is expressed as a percentage.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical field capacity range for different soil types?
A: Field capacity varies by soil type: sandy soils (10-20%), loamy soils (20-30%), and clay soils (30-45%).

Q2: How is water retained measured in practice?
A: Typically measured by saturating a soil sample, allowing it to drain for 24-48 hours, then measuring the water content.

Q3: Why is field capacity important for irrigation?
A: It helps determine when to irrigate (when soil moisture drops below 50-60% of field capacity) and how much water to apply.

Q4: How does field capacity relate to permanent wilting point?
A: Field capacity represents the upper limit of plant-available water, while permanent wilting point represents the lower limit.

Q5: Can field capacity change over time?
A: Yes, field capacity can be affected by soil compaction, organic matter content, and soil structure changes.