Louisiana Yards and Neighborhoods

1
Louisiana Yards and Neighborhoods

• Water Efficiently!

2
Water efficiently!

• Plants
• Soils
• Systems
• Mechanics

3
Plants

• Plant water needs
• Water movement
• Evaporation and transpiration
• Evapotranspiration
• ET-LAIS (EvapoTransporation values from Louisiana
  Agriclimatic Information System)
• Temperature vs. relative humidity

4
Plant Water Needs

• Germination
• Vegetative phase
• Reproductive phase
• Transpiration cools plant, provides suction to
  pull water and nutrients from the soil into roots
  
• Plants have differing water needs

5
Water Movement
6
Evaporation and Transpiration

• Evaporation dominates vegetative phase of growth
  and increases with increased frequency of
  irrigation.
• Transpiration dominates reproductive phase of
  growth and is affected by plant density,
  mono-culture/mixed bed, exposure to sun, wind and
  built environment.

7
Evapotranspiration
8
ET-LAIS

• To find ET values at LAIS weather stations
• http//www.lsuagcenter.com/weather/Etotabledata.a
  sp
• A description of ET use http//www.lsuagcenter.co
  m/weather/potentialUseOfETOData.asp

9
Temperature vs. Relative Humidity
10
Soil (or Media)

• Porosity
• Permeability
• Field capacity
• Wilting point
• Available water holding capacity
• Soil texture
• Water intake rate and depth
• Compaction

11
Soil Porosity

• Volume of pore space within a given volume of
  soil ().
• Pore spaces are available for air and/or water
  and/or roots.
• When soil is saturated with water, there is no
  room for air.
• Roots (of most plants) will not grow into water.

12
Soil Permeability

• How fast can water move into/through soil
  (inches/hour)?
• Higher in dry soil, lower in wet soil
• Higher in soils with larger pore spaces (sands,
  loams)
• Lower in soils with smaller pore spaces (silts,
  clays)

13
Soil Field Capacity

• Moisture content of soil 24-48 hours after
  saturation.
• Gravity causes free water to drain down below
  root zone.
• Air moves into pore spaces as water drains.
• Water is readily available to plant.
• Moisture content at field capacity may be sand
  10, silt loam 20, clay 50.

14
Soil - Wilting Point

• Moisture content of soil after plant has removed
  all the water it can.
• Moisture content at wilting point may be
• Sand 1
• Silt loam 5
• Clay 25

15
Soil Available Water-holding Capacity

• Available water holding capacity (AWHC) field
  capacity minus wilting point.
• AWHC for sand may be 10-1 9, or .09 x 12
  inches/foot 1.08 inches/foot.
• AWHC for silt loam may be 20-5 15, or .15 x
  12 inches/foot 1.8 inches/foot.
• AWHC for clay may be 50- 35 15, or .15 x 12
  inches/foot 1.8 inches/foot

16
(No Transcript)
17
(No Transcript)
18
Soil Compaction

• Compaction reduces both porosity and
  permeability.
• Compaction can be increased by traffic, tillage
  and chemical changes such as adding sodium or
  calcium.
• Soil compacts easily when wet.

19
Systems

• Garden furrow irrigation
• Lawn sprinkler irrigation
• Drip or micro irrigation

20
Systems Garden Furrow Irrigation

• High losses of water to evaporation and
  percolation below root zone
• Low distribution uniformity as water travels down
  the row
• Short-term saturation of soil pore spaces
• Wet furrows after irrigation

21
Systems Lawn Sprinkler Irrigation

• If properly designed, installed, maintained and
  operated, sprinklers provide most efficient means
  for uniform irrigation of lawns.
• Higher pressure requirements 30-60 pounds per
  square inch (psi) than furrow or drip irrigation.
• Easily automated.

22
Systems Drip/Micro Irrigation

• Facilitates daily or more frequent irrigation to
  reduce plant moisture stress
• Low pressure requirements 10-15 pounds per
  square inch (psi)
• Low flow rates gallons per hour (gph) instead of
  gallons per minute (gpm)
• Easily modified as needed

23
Mechanics

• Basics
• Flow restrictions
• Schedule 40 PVC pipe flow rates
• Drainage

24
Mechanics Basics

• Flow rate gallons/minute (gpm) or inches/day.
• Pressure pounds/square inch (psi).
• Pressure is lost from pipe friction and other
  restrictions to flow.
• Freeze protection exposed PVC is at risk below
  20 degrees.
• Backflow protection is essential.

25
Mechanics Basics(continued)

• Electronic controllers available to automate
  system.
• Filtration is essential for drip or micro
  systems.
• Water quality check pH, salts, sodium, iron,
  manganese, calcium.
• Chemigation is possible.
• Maintenance is essential.

26
Mechanics Flow Restrictions

• Water flowing through a pipe creates friction,
  which reduces pressure.
• Changing water flow direction reduces pressure.
• The labor to install a 1-inch pipe is the same as
  for a ¾-inch pipe, but friction losses are
  greatly reduced.

27
Mechanics Schedule 40 PVC Pipe Flow Rates
28
Mechanics Drainage

• Design landscape to drain.
• Surface drainage is the only practical solution.
• Subsurface drainage is absolutely the last
  resort.
• Divert drainage coming onto landscape from your
  roof, driveway or your neighbors yard.

29
Louisiana Yards and Neighborhoods

• Water Efficiently!