Calculate Field Capacity Of Soil

Field Capacity Formula:

\[ FC = \frac{\text{Water Retained}}{\text{Soil Volume}} \times 100 \]

Field Capacity (FC):

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1. What is Field Capacity?

Field capacity refers to the maximum amount of water that soil can retain against the force of gravity after being saturated and allowed to drain. It represents the water content remaining in soil 2-3 days after irrigation or rainfall.

2. How Does the Calculator Work?

The calculator uses the field capacity formula:

\[ FC = \frac{\text{Water Retained}}{\text{Soil Volume}} \times 100 \]

Where:

\( FC \) — Field Capacity (%)
\( Water Retained \) — Volume of water retained in soil (m³)
\( Soil Volume \) — Total volume of soil sample (m³)

Explanation: The formula calculates the percentage of water that soil can hold after free drainage has occurred.

3. Importance of Field Capacity Calculation

Details: Field capacity is a critical parameter in agriculture, irrigation planning, and soil science. It helps determine optimal watering schedules, predict plant water availability, and assess soil drainage characteristics.

4. Using the Calculator

Tips: Enter water retained and soil volume in cubic meters (m³). Both values must be positive numbers. The result represents the field capacity as a percentage.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical field capacity range for different soil types?
A: Sandy soils: 10-20%, Loamy soils: 20-30%, Clay soils: 30-45%. These values can vary based on organic matter content and soil structure.

Q2: How is field capacity measured in practice?
A: Typically by saturating a soil sample, allowing it to drain for 2-3 days, then measuring the water content. Laboratory methods include pressure plates or centrifugation.

Q3: How does field capacity relate to plant available water?
A: Field capacity represents the upper limit of plant available water. The difference between field capacity and permanent wilting point defines the total available water for plants.

Q4: Can field capacity change over time?
A: Yes, field capacity can be affected by soil compaction, organic matter content, soil structure, and management practices like tillage.

Q5: Why is field capacity important for irrigation management?
A: It helps determine when to irrigate (at depletion of available water) and how much water to apply (to refill to field capacity without causing drainage losses).