This document compares three types of water found in soil: gravitational water, capillary water, and hygroscopic water. Gravitational water is stored in larger soil pores and moves down through soil via gravity. Capillary water is held in smaller pores and moves up via capillary action, making it available to plants. Hygroscopic water is bound to soil particles and does not move or supply plants.

1. Parameter Groundwater Capillary Water
Storage
location
Stored in soil or rock layers
below the surface
Held in the small spaces
between soil particles
Depth Deeper underground Closer to the soil surface
Accessibility
to plants
Usually not accessible to
plants
Accessible to plants
Extraction by
plants
Not directly extracted by
plants
Extracted by plants through
their roots
Replenishment
Replenished by infiltration of
precipitation or surface water
Replenished by
precipitation
Importance
Important for human use,
such as for drinking and
irrigation
Essential for plant growth

2. Parameter
Gravitational
Water Capillary Water
Hygroscopic
Water
Storage
location
In the larger pores
and spaces between
soil particles
In the smaller pores
and spaces between
soil particles
Adsorbed onto the
surfaces of soil
particles
Movement
Moves down through
the soil due to
gravity
Moves upward due
to capillary forces
Does not move
with water,
remains bound to
soil particles
Availability to
plants
Not available to
plants
Available to plants
Not available to
plants
Importance
Can cause leaching
of nutrients and
pollutants
Important for plant
growth
Not important for
plant growth