Water-holding capacity is defined as the water retained between field capacity and wilting point. Field capacity is the saturated state of water in the soil that can drain freely due to the force of gravity. Wilting point is the soil water level after its absorption by a plant.
The water that remains in the soil after draining is held by a force greater than gravity. The water level in the soil that can no longer be absorbed by the plants is referred as the permanent wilting point, and this water is strongly attached to the soil particles. The available water to the plant is considered to be 50 percent of the soil's water-holding capacity. The water level that is held by the soil between saturation and field capacity is referred as gravitational water.