A soil water characteristic curve (SWCC) is a graphical representation of the relationship between soil water content and soil water potential. It is a fundamental tool for understanding the behavior of water in soils and is used in a wide variety of applications, including irrigation scheduling, soil physics, and geotechnical engineering.
What is the Best Measure of Moisture?
The best measure of moisture for a specific application depends on that application’s requirements. Some of the most common measures of moisture include:
- Soil water potential
- Soil water content
- Volumetric water content
- Gravimetric water content
- Neutron probe
- Tensiometer
- Moisture meter
The SWCC can be used to determine the amount of water that is available to plants, the rate at which water will move through the soil, and the soil’s ability to store water.
The SWCC is typically divided into three zones:
1. The saturated zone
In the saturated zone, all of the soil pores are filled with water. The soil water potential is zero, and the soil water content is at its maximum.
2. The unsaturated zone
In the unsaturated zone, some of the soil pores are filled with water and some are filled with air. The soil water potential is less than zero, and the soil water content is less than its maximum.
3. The dry zone
In the dry zone, most of the soil pores are filled with air. The soil water potential is very low, and the soil water content is very low.
The SWCC is a valuable tool for understanding the behavior of water in soils. It can be used to design irrigation systems, predict the movement of water through the soil, and assess the stability of slopes.