SOIL WATER MOVEMENT Cause changes in the physical, chemical and biological properties of soils. SOIL WATER MOVEMENT FACTS. SOIL WATER PLANTS RELATIONSHIP.

2.  Cause changes in the physical, chemical and
biological properties of soils.
 Causes the soil particles to swell and shrink.
 Soil EC.
 Soil pH.
 Soil Structure (porosity).
 Part of chemical reactions that release and tie up
plant nutrients.
 Soil air and water ratio.
 Soil microbial population.
 Leaches excessive salts/contaminants.
 Main carrier for excessive salts and sodium.

3.  Determine the rate of soil water movement:
 Drainage.
Leaching of salts/contaminants and nutrients.
Shallow water-table depth.
 Surface runoff.
Soil erosion.
Contamination of surface water sources.
 Evapotranspiration.
Rate of soil water retention.
 Rate of change in soil temperature.
 Rate of organic material decomposition.
 Type and population soil microorganisms.

4.  Kinetic Energy: when water (not soil water) is
flowing in a river in rapid and turbulent flows.
 Potential Energy: determines the status and
movement of soil water (moving very slowly).
 Like all substances, soil water move from
higher to lower energy level.

6. Gravitational Water:
Free water
Macro-pores
Moves rapidly under good soil
drainage conditions
Is not available to plants
Under poor soil drainage
conditions, cause plant wilting
due to lack of soil oxygen Courtesy
of
F.
Casey

7. Under good soil drainage:
 Leaches excessive salts
 Oxygen
Under poor soil drainage:
High groundwater levels
Lack of soil oxygen
Buildup of excessive salts
How do you improve conditions?
Build aggregates
Rooting channels
Reduce compaction
Use water with crops
Subsurface and Surface drainage

8. Capillary Water:
 Plant available
water
 Tension
Adhesion (attraction
to soil)
Cohesion (attraction
to water)
 Evaporation
Courtesy of F. Casey

9. Can move to any direction
from wet areas (low soil
moisture tension) to dry
area (high soil moisture
tension).

10. Under good soil drainage:
Movement remains restricted below the rooting
zone of most of the crops, due to low
groundwater levels
No buildup of excessive salts
Under poor soil drainage:
Excessive buildup of salts
Poor growth environment

11.  Plant available water is between FC and PWP
moisture levels.
 Gravitational water is excess water.
 Gravitational forces cause the downward
movement of soil water under good soil
drainage conditions.
 Slow or poor movement of gravitational water
will cause saturated conditions, high
groundwater levels and surface runoff.
 Subsurface drainage system will only collect
gravitational water.

12.  Soil water moves quickly through the larger pores, as it is
held more tightly in the smaller pores.
 Water will not move from the smaller pores to larger pores
unless conditions are saturated.
 Tortuosity of the soil pores also restricts the soil water
movement.
 Water moving along the pore walls versus center will move
slowly.
 Adhesion and cohesion forces cause the capillary soil
water movement/rise.
 High groundwater levels combined with soil surface
evaporation will maximize capillary rise.
 Capillary rise will be maximized for heavier soils.
 Preserving top soil moisture will minimize capillary rise.