1. Water & Solute Movement
A solid, liquid, or gas that is dissolved in a liquid to make a solution.
When the solute has an electrical charge, the mobility of the solute is affected

2. Soil Properties & Water Movement
Infiltration
The ability of water to move into the soil from the soil surface
Permeability
The ability of water to move through the soil horizon after it has penetrated the surface
Is controlled by its least permeable horizon

3. Soil Properties & Water Movement
Solute movement is affected by pH OM
CEC
Soil texture
Soil structure

4. Soil Properties & Water Movement
Soil pH influences the solubility and ionic state of a solute and thus influences its mobility
OM can absorb and adsorb many times its own weight, tying up solutes with the notable exception of K, thus reducing their mobility
CEC reflects the number of binding sites available for a positively charged solute to bind to

5. Soil Properties & Water Movement
Soil texture: Finer textured soils usually have a higher CEC and less movement of solutes
Soil Structure: Well-structured soils allow for more movement of solutes down into the soil profile
Reduces the risk of runoff
Increases the chance of solute movement into a shallow water supply

6. Soil Properties & Water Movement
Other factors that affect solute movement:
Timing
Rate of application
Tillage
Conservation practices
Irrigation

7. Soil Properties & Water Movement
Timing of a solute applied close to time of crop use has less time for excessive movement.
Rates of application above what is needed for crop production can lead to excessive leaching, runoff, or residual.
Tillage promotes good infiltration and reduces runoff potential

8. Soil Properties & Water Movement
Tillage (contd)
Breaks up non-permeable zones
Improves water use
Conservation practices, like terracing, strip cropping, etc.. all trap water and soil particles and thus, the dissolved and retained solutes.
Irrigation can increase solute leaching

9. Nutrient Movement in the Soil & Water
Non-Point Source Pollution: Cannot be traced to a specific location point or time of entry.
Ag chemicals from field runoff
Nitrate movement into ground water
Point Source Pollution: Entry into the environment can be traced to a single event or sequence of events at an inclusive location
Chemical spill at a well head
Fertilizer spill into a storm sewer

10. Plant & Water Relationships
Evapotranspiration (ET):
The loss of water from the soil by both surface evaporation and plant transpiration
Is influenced by stage of crop growth, water status, and soil water potential
As the crop grows, evaporation tends to decrease and transpiration increases
As the soil water decreases, more energy is required to remove water from the soil

11. Plant & Water Relationships
Wind
Increases evaporation losses
Increases transpiration losses to a point….
Temperature works the same way wind does
Warm air can hold more water (humidity) than cold air
Solar radiation (sunlight) eventually becomes heat energy

12. Plant & Water Relationships
Relative humidity
A measure of the concentration of water vapor in the air
The higher the Relative Humidity the less likely there will be a need for supplemental water

13. Plant & Water Relationships
Plant canopy
Reduces soil evaporation but increases transpiration
Evapotranspiration is not proportional to the amount of size of plant canopy, but does trend higher as the plant canopy expands

14. Plant & Water Relationships
How plants lose water
Stomata on leaf surfaces
Stomata open and close according to temperature, humidity, wind, and soil water supply
98% of the water transpired is used to cool the plant

15. Plant & Water Relationships
Excessive soil moisture
Reduces nutrient availability
Reduces oxygen availability for root growth
Roots can begin to die within 48 hours
Denitrification in water-logged soils can account for major nitrogen losses

16. Plant & Water Relationships
Soil Moisture Deficiency
Plant requires more energy to move water
Affects nutrient movement & uptake
N movement by mass flow
K movement by mass flow & diffusion
P movement by diffusion

17. Water Holding Capacity
Type
Available Water (in/ft)
Course sand to 0.75
Fine sand to 1.00
Loamy sand to 1.20
Sandy loam to 1.40
Fine sandy loam to 2.00
Silt loam to 2.50
Silty clay loam to 2.00
Silty clay to 1.70
Clay to 1.50

18. Available Water Handout

19. Permeability Classification System

21. The Hydrologic Cycle

23. Water Quality Concerns Ground water contamination
Surface water contamination
Nitrate can contaminate both
Nitrate reported in two ways
Nitrate NO ppm (or mg/l)
Nitrate-N NO3-N 10 ppm (or mg/l)

24. Water Quality Health affects of nitrate in drinking water
Methemoglobinemia (Blue Baby Syndrome) which is the result of poor O2 transport in the blood of very young babies
Formation of nitrosamines, known carcinogens that form when nitrates react with organic compounds

25. Water Quality Water Contamination Occurs often at well heads
Considered a point-source pollutant
Can enter through cracked casings, improper seals, or ponded contaminants near well head
Sources of information about drinking water standards: US EPA, State Public Health and Environmental Agencies

26. Water Quality Prevention of water contamination
Use anti-backsiphoning devices
Never fill or dump pesticides or fertilizers near a well head
Fill depressional areas around a well head

27. Sediments & Surface Water Quality
Sediments settle out of the water stream
As the flow of the water slows
In reduced water temperature
Sediments are considered pollutants
The sediment itself
Contaminants bound to the sediment
Phosphorus contamination is primarily through sediment contamination (organic P exception)

28. P and N Effects on Surface Water Quality
Causes eutrophication where algae and weeds flourish
Eutrophic waters have
High nutrient levels
Low species diversity
Low dissolved oxygen
Poor taste and odor
Excessive vegetation (slows flow and….)
Can be turbid and cause fish kills

29. Preventing Surface Water Contamination
Filter/buffer strips
Plant along surface water shores
Slows water movement and causes sediment to drop out before entering the main body of water
Riparian Areas or Tree Plantings
Serves the same purpose as above
Both methods are effective in using up nitrates and phosphorus.