Water

1
Water Transpirationor Water, water
everywhere and all the boards did shrink. Water,
water everywhere and not a drop to drink.
2
Potential Evapotranspiration/ Las Cruces

• PET evaporation transpiration from a crop
  under non-stressed conditions
• Adjusted to a reference crop (grass)
• Crop coefficient (kC) ETC / ETO
• Function of T, RH, season, leaf area, shading,
  crop species, soil moisture

3
Las Cruces Potential Evapotranspiration
Water (in/d)
4
Trees and Water Turfgrass Actual Water Use /
Farmington NM/ D. Smeal
5
Trees and Water Turfgrass Actual Water Use/
Farmington NM /D. Smeal
6
Trees and Water How often should new trees be
watered?
7
Irrigation Scheduling-nonstressed

• Fancy formula
• PAW AWC x MAD x RZ
• Sooo,
• Plant Available Water
• soil Available Water Content x Maximum
  Allowable Depletion x Root Zone depth

8
Pecan Water Use/ Sammis et al.
9
Water Transpiration Irrigation Water
Management

• Evapotranspiration water loss through
  evaporation and transpiration
• Yearly ET 200 cm
• Yearly Ppt 20 cm
• Deficit 180 cm
• Daily ET (cm/d)
• Mar Apr May Jun Jul Aug Sep Oct
  0.13 0.25 0.41 0.61 0.71 0.61 0.41 0.20

10
Water Transpiration Irrigation Water
Management

• Goals of Irrigation
• Meet the needs of the plant
• Minimize runoff
• erosion
• chemicals
• Minimize evaporation
• Manage leaching
• salts
• NO3

11
Water Transpiration Irrigation Water
Management

• When to Irrigate?
• Observe plants--too late!
• Observe soil--touchy-feeley
• Measure soil or plant water stress
• tensiometer neutron probe
• pressure bomb electrical resistance
• leaf temperature
• Estimate water use
• evapotranspiration

12
Water Transpiration Irrigation Water
Management

• Reducing Water Use in the Landscape
• Goal Reduce evaporation
• water at night or early morning
• water deep to develop deep rooted plants
• apply 5 cm organic mulch to cool soil
• Goal Put the water where you want it
• directional sprinklers
• berms or swales

13
Water Transpiration Irrigation Water
Management

• Reducing Water Use in the Landscape
• Goal Use low water plants
• xeriscaping
• plant breeding
• not zeroscaping
• Goal Improve irrigation efficiency
• drip irrigation
• sub-irrigation

14
Things to Know

• Transpiration
• Turgor
• Wilting
• MAD
• RH
• AWC
• Water Potential
• Xeriscaping

• Colligative properties
• Hydrologic cycle
• Irrigation
• Solvent
• Solute
• Field Capacity
• Permanent Wilting Point
• Water Use Efficiency
• Potential Evapotranspiration

15
Water TranspirationFactors Influencing
Transpiration/ Musk mallow leaves
Base of Plant
Top of Plant
16
Water TranspirationHeat of Fusion/Frost
protection in vineyard
495 L/min/ha
103 L/min/ha
17
Water TranspirationHeat of Vaporization/ Peach
bud bloom delay
18
Water TranspirationFactors Influencing
Transpiration/ Light, T, H2O
Citrullus colocynthis
Excised leaf
Air T
Intact leaf