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Louisiana Yards and Neighborhoods
Louisiana Yards and Neighborhoods
Water Efficiently!Water Efficiently!
www.lsuagcenter.com/lyn
Water efficiently! Water efficiently!
• Plants
• Soils
• Systems
• Mechanics
• Plants
• Soils
• Systems
• Mechanics
PlantsPlants
• Plant water needs
• Water movement
• Evaporation and transpiration
• Evapotranspiration
• ET-LAIS (EvapoTransporation values from Louisiana Agriclimatic Information System)
• Temperature vs. relative humidity
• Plant water needs
• Water movement
• Evaporation and transpiration
• Evapotranspiration
• ET-LAIS (EvapoTransporation values from Louisiana Agriclimatic Information System)
• Temperature vs. relative humidity
Plant Water NeedsPlant 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
• 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
Water MovementWater Movement
Evaporation and TranspirationEvaporation 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.
• 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.
EvapotranspirationEvapotranspiration
ET-LAISET-LAIS
• To find ET values at LAIS weather stations: http://www.lsuagcenter.com/weather/Etotabledata.asp
• A description of ET use: http://www.lsuagcenter.com/weather/potentialUseOfETOData.asp
Temperature vs. Relative HumidityTemperature vs. Relative Humidity
Soil (or Media)Soil (or Media)• Porosity
• Permeability
• Field capacity
• Wilting point
• Available water holding capacity
• Soil texture
• Water intake rate and depth
• Compaction
• Porosity
• Permeability
• Field capacity
• Wilting point
• Available water holding capacity
• Soil texture
• Water intake rate and depth
• Compaction
Soil – PorositySoil – 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.
• 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.
Soil – PermeabilitySoil – 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)
• 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)
Soil – Field CapacitySoil – 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%.
• 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%.
Soil - Wilting PointSoil - 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%
• 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%
Soil – Available Water-holding Capacity
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
• 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
Soil – CompactionSoil – 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.
• 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.
SystemsSystems
• Garden furrow irrigation
• Lawn sprinkler irrigation
• Drip or micro irrigation
• Garden furrow irrigation
• Lawn sprinkler irrigation
• Drip or micro irrigation
Systems – Garden Furrow IrrigationSystems – 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
• 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
Systems – Lawn Sprinkler IrrigationSystems – 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.
• 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.
Systems – Drip/Micro IrrigationSystems – 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
• 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
MechanicsMechanics
• Basics
• Flow restrictions
• Schedule 40 PVC pipe flow rates
• Drainage
• Basics
• Flow restrictions
• Schedule 40 PVC pipe flow rates
• Drainage
Mechanics – BasicsMechanics – 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.
• 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.
Mechanics – Basics(continued)
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.
• 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.
Mechanics – Flow RestrictionsMechanics – 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.
• 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.
Mechanics – Schedule 40 PVC Pipe Flow Rates
Mechanics – Schedule 40 PVC Pipe Flow Rates
Diameter (in) ½ ¾ 1 1 ¼ 1 ½ 2
Flow (gpm) 4 8 12 22 30 50
Velocity (ft/sec) 4.2 4.8 4.4 4.7 4.7 4.8
Loss (psi/100’) 5.6 5.1 3.4 2.7 2.3 1.7
Mechanics – DrainageMechanics – 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 neighbor’s yard.
• 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 neighbor’s yard.
Louisiana Yards and Neighborhoods
Louisiana Yards and Neighborhoods
Water Efficiently!Water Efficiently!
www.lsuagcenter.com/lyn
