Transcript ENVIRONMENTAL FACTORS

ENVIRONMENTAL FACTORS
LIGHT
Turf needs at least 4 hours of full sun
• Bermudagrass 6 hours
– ‘Tifgrand’ and ‘Celebration’
• 60% shade
LIGHT
Shade
• Less PS, less CHO
• Not as stress tolerant
• Reduced density
LIGHT
Shade Symptoms
• Shallow rooting
LIGHT
Shade Symptoms
• Succulent growth for pests
LIGHT
Shade Turfgrass
• St. Augustine and Carpetgrass best
LIGHT
Trees
• Compete for moisture and nutrients
• Reduces amount and quality of light
• Allelopathy: chemical warfare
LIGHT
Shade Management
• Shade tolerant turf, groundcover, or mulch
LIGHT
Shade Management
• Reduce traffic
LIGHT
Shade Management
• Raise mowing height
LIGHT
Shade Management
• Reduce N fertilization
– Nitrogen forces growth
– Consumes what little CHO is produced in
shade
LIGHT
Shade Management
• Root prune trees
• Reduces root competition
TEMPERATURE: HEAT
High respiration, low CHO production
TEMPERATURE: HEAT
Evapotranspiration
• Evaporation: water changes from liquid
to gas
• The conversion requires energy and
absorbs heat
TEMPERATURE: HEAT
Evapotranspiration
• Transpiration: water evaporates from
openings, stomates, of leaves
• Water as liquid goes through plant and
changes to gas at stomates
• Cools plant by absorbing heat!
TEMPERATURE: HEAT
Heat Management
• Transpiration: provide adequate
moisture
– Syringing, short cycles of irrigation on golf
greens
TEMPERATURE: HEAT
Heat Management
• Wind: promote air circulation
– Increase transpiration
TEMPERATURE: COLD
• Occur when temps below 20F
• Turf looks water soaked
TEMPERATURE: COLD
Cold damage worse when:
• Poor drainage
TEMPERATURE: COLD
Cold damage worse when:
• Excessive thatch
TEMPERATURE: COLD
Cold damage worse when:
• Shade
TEMPERATURE: COLD
Cold damage worse when:
• Excessive fall N
TEMPERATURE: COLD
Cold damage worse when:
• Close mowing
TEMPERATURE: COLD
Cold Management
• Cold hardy turf
• Establish turf
• August last N
• Apply K
MOISTURE
• Maintains cell turgidity (footprinting)
• Transports nutrients
• Transpiration
MOISTURE
Wet Turf
• Lack of oxygen to roots
• Disease
• Compaction
MOISTURE
Wet Turf Management
• Install drainage
MOISTURE
Wet Turf Management
• Grade surface drainage and re-establish
turf
MOISTURE
Wet Turf Management
• Disease resistant turf
MOISTURE
Wet Turf Management
• Avoid traffic
MOISTURE
Wet Turf Management
• Plant groundcover or mulch
MOISTURE
Drought Resistance
• Varies among species and cultivars
• Remove thatch
• Encourage deep roots
– Deep and infrequent irrigation
• Avoid fertilization during drought unless
irrigation is provided
MOISTURE
Dew
• Water accumulation in morning hours
• Condensation and guttation
MOISTURE
Condensation
• Water vapor content, or relative humidity
• Amount of water vapor that can be held
by the air is proportional to air
temperature
MOISTURE
Condensation
• Increasing air temp, increase water
content
• Temperature drop causes condensation
MOISTURE
Nutrient-rich water
• Guttation: diffusion of plant moisture
through openings at ends of leaves
• Water pressure builds up in roots due to
low transpiration
MOISTURE
Nutrient-rich water
• Nutrients enhance disease
• Cause minor tip burn (salts)
MOISTURE
Dew Management
• Syringing greens to wash off nutrients
• Dew whip
MOISTURE
Frost
• Dew forming ice crystals at about 38 F
• Avoid traffic on heavy frosted turf
• Damage leaves, will not kill crown
• Frost symptoms
SALINITY
• High salt levels cause turf to weaken and
decline in quality
CAUSES OF SALINITY
• Salts not leached excess from soil
• High ET rates
– Leave behind salts
SALINE SYMPTOMS
• Initially resemble drought stress
– Shoot browning
– Narrow, stiff and darker to blue-green
EFFECTS ON PLANTS
• Inhibits osmotic water absorption
– Can even remove water from roots
EFFECTS ON SOIL
• Deterioration of soil structure
• Clog pores, reduces soil aeration and
infiltration
TURF RESISTANCE
• Seashore paspalum, bermuda (hybrids
more tolerant), St. Augustine, and zoysia
SALINE MANAGEMENT
• Test water and soil