1. Louisiana Yards and Neighborhoods Water Efficiently! www.lsuagcenter.com/lyn

2. Water efficiently! Plants Soils Systems Mechanics 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 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 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. 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.asp A description of ET use: http://www.lsuagcenter.com/weather/potentialUseOfETOData.asp http://www.lsuagcenter.com/weather/potentialUseOfETOData.asp 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 http://www.lsuagcenter.com/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 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. 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) 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%. 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% 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 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

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. 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 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 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. 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 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 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. 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. 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. 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 Diameter (in)½¾11 ¼1 ½2 Flow (gpm)4812223050 Velocity (ft/sec)4.24.84.44.7 4.8 Loss (psi/100’)5.65.13.42.72.31.7

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 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.

29. Louisiana Yards and Neighborhoods Water Efficiently! www.lsuagcenter.com/lyn