Soil water content at -1/3 bar (or -33 kPa) is the volumetric percentage of water a soil retains at field capacity—the point after gravitational water has drained away. It is commonly used to define the upper limit of plant-available water. The amount of water held at this tension depends on soil properties including texture, structure, bulk density, and organic matter content.
Applied Relevance
Water content at -1/3 bar is used in hydrologic modeling, irrigation scheduling, and soil health assessments. It serves as the starting point for estimating available water capacity (AWC) when paired with -1,500 kPa (wilting point) data. For example, subtracting water content at wilting point from -1/3 bar provides an estimate of the total water available to plants.
Available Depths
Water content data is available for the following depth intervals:
0–5 cm, 5–20 cm, 0–20 cm, 0–30 cm, 0–50 cm, 0–100 cm, 0–150 cm, and 150–200 cm.
