The document discusses various environmental factors that can affect turfgrass growth and quality. It describes how professional turfgrass managers recognize changes in factors like water, temperature, light, and wear/damage in order to adapt their maintenance practices accordingly. Maintaining proper soil and root conditions helps turfgrass better tolerate environmental stresses. The document provides details on specific stresses and how different turfgrass species vary in their tolerance.

1. Environmental Stress on
Turfgrass
LNT 132 – Spring 2017
Mark Valen

2. Environmental Effects on
Turfgrasses
The best professional turfgrass managers are “proactive”
rather than “reactive”.
They recognize changes in the environment and know
how they can affect the growth and the quality of the
turfgrass they manage.
They then adapt their maintenance practices to reduce
the effects of environmental changes around their turfs.

3. Water
• Used to transport nutrients
• Cools and insulates the plant
• Gives support and turgidity to the plant
• Needed in photosynthesis
Grass contains 75-85% water by weight and is found in
greatest concentrations in young leaves

4. Water Absorption
Roots:
• Primary method of water uptake
• Absorption potential depends on quantity and
depth of roots
• Root hairs absorb the water
Root hairs

5. Water Absorption
• Available water influenced by:
• precipitation
• irrigation
• water table
• soil water holding capacity
• salt concentrations
• Foliar absorption
• water can enter leaf as a liquid from dew or syringing
• wilted leaves absorb more water than non-wilted leaves

6. Water Use Rates
• Total amount of water required for growth plus the
quantity lost by transpiration from the leaves and
by evaporation from the soil.
• Quantities of water lost per day:
• .1 - .3” per day in cool to warm weather
• .3 - .45” per day in warm to hot & dry weather

7. Water Use Rates
Cultural factors influence water use rate
• mowing: increase the cutting height increases WUR
• dull mowers: increases WUR due to damaged turf
blades
• fertilizer - increases WUR due to increased growth
• disease and traffic - increase WUR due to damaged turf
blades

8. Drought
Drought is a condition of prolonged water stress
which limits or prevents turfgrass growth.
The severity of drought damage depends on:
• the length of time without precipitation
• the evaporative power of the air
• the soil type
• the turfgrass and its rooting depth

9. Adaptation to Drought
Avoidance (annual grasses)
• short life cycle
• heavy seed production
• germinate only in wet weather
Dormancy (perennial grasses)
• no shoot growth in drought conditions
• crown survives until rainfall resumes

10. Adaptation to Drought
Water absorption ability
• deep rooting
• more total roots and root hairs
Structural
• decreased leaf surface
• fewer number of stomata
• rolling or folding of leaves
• presence of leaf hairs
Drought hardiness
• can withstand desiccation

11. Drought Tolerant Grasses

12. Wilt
• visible drooping, rolling,
or folding of turfgrass
leaves as a result of lack
of turgidity due to water
loss.
• gray, blue-green
appearance to leaf
surfaces.
• turf fails to spring back
when walked on, leaving
footprints.

13. Wilt
Weather related:
• high temperatures
• wind
• solar radiation (sunlight)
• low humidity
Maintenance related- poor rooting
• lack of oxygen
• excess N fertilizer
• waterlogged soils
• high salts
• compacted soils

14. Flooding
• Erosion:
• the movement of soil and turf
• Deposition of soil, salt, and debris:
• may bury turf
• may form a compacted layer that stops water and air
infiltration
• salt can kill turf (more common in desert flash floods)
• Direct injury due to submersion:
• lack of oxygen kills turfgrass roots

15. Flood Damage

16. Scald
leaf death due to
water standing on
the surface when
high temperatures
and bright sunlight
are present
• causes brown spots
on low areas of turf
• the exact reason for
this death of turf is
not known

17. Scald

18. Light
• Absorbed by upper and lower leaf surfaces
• Since some of the green tissue is removed during mowing, it
is very important for the remaining leaves to absorb the
maximum amount of light.
• = C6H12O6 +

19. Shade
Shade is partial or complete interception of solar
radiation
• reduction in carbohydrate reserves
• decreased growth of roots, stems, rhizomes, and
stolons
• thin, elongated leaves
• wilting due to poor rooting and competition of
nearby tree roots
• reduced tolerance to heat, cold, drought, and traffic

20. Managing Grass in the Shade

21. Managing Grass in the Shade
• Raise cutting heights
• Avoid excessive nitrogen applications
• Practice deep, infrequent waterings
• Avoid traffic on the shaded area
• Watch closely for insects and diseases
• Eliminate low, overhanging branches to 8-10’
• Quickly rake up fallen leaves and debris

22. Shade Tolerance of Grasses
1. Red Fescue
2. St. Augustine
3. Creeping Bent
4. Tall Fescue
5. Zoysiagrass
6. Colonial Bent

23. Temperature
• Most turfgrass growth occurs between 40-105
degree F.
• In many cases, the root temperature is more
important than the shoot temperature.
• Cool season: 60 - 75 °F
• Warm season: 80 - 95 °F

24. High Temperature Stress
• Stress is usually caused by a combination of heat,
wear, desiccation, and disease.
• Steps in heat stress death:
1. root maturation and death
2. decline in shoot growth
3. decline in leaf elongation and width
4. lack of vigor as respiration exceeds photosynthesis

25. Common Signs of Heat Stress
• Wilting
• Lack of upright growth
• Thinning of turf blades
• Dry and dead spots on turf, especially in higher
areas and compacted areas.
• Death of areas of turf that have low density, or
shady areas that are suddenly exposed to the sun.

26. Methods to Lessen Heat Stress
• Choose a more heat tolerant grass.
• Aerify and irrigate compacted areas before high
heat begins.
• Inspect irrigation system for proper coverage
• Mow higher to keep soil temperatures down.
• Avoid over-stimulation: do not fertilize during high
heat periods.
• “Syringe” the area during the mid-day heat

27. Syringing
Syringing is a common practice of lightly watering the turf to cool
the turf canopy, prevent turf wilt, and remove dew or exudates
from the leaf as a means to avoid turf diseases.

28. Low Temperature Stress
• Decrease in respiration and photosynthesis
• Slowing growth process leading to dormancy
• Lower internal plant temperature
• Eventual freezing of the protoplasm of the cell
• Ruptures the cell wall leading to damage or death of
turf.

29. Low Temperature Stress
• Leaf surfaces and young roots are easily frozen while
the stems and crown are more insulated.
• Mild freezing may only affect leaves and some roots.
• Thus grass may recover the following spring.

30. Low Temperature Kill
• Poor surface drainage (ice forms)
• Excessive nitrogen (thin blades and shoots)
• Low potassium levels (weak cell walls)
• Excessive irrigation (shallow roots)
• Low cutting height (less insulation)
• Walking on frosted turf

31. Temperature Hardiness of Grasses
• High Temperature Hardiness
1. Zoysia
2. Bermuda
3. St. Augustine
4. Buffalograss
5. Tall Fescue
6. Paspalumgrass
Low Temperature Hardiness
1. Creeping Bent
2. Kentucky Blue
3. Colonial Bent
4. Annual Bluegrass
5. Red Fescue
6. Tall Fescue

32. Air Quality
Oxygen O2
• Manufactured in photosynthesis
• Never deficient in leaves and shoots
• Can be deficient in roots due to poor drainage,
compacted soil, saturated soils, or heavy thatch
accumulation.
• Lack of oxygen slows and stops respiration which
can lead to root death.

33. Air Quality
Carbon dioxide - CO2
• Required for photosynthesis
• Grass gets CO2 from air and soil
• Almost never deficient except in air stagnant areas
• Hot, humid morning with turf tucked in the trees
• Roots do not need CO2 but must be able to release
CO2 into the soil and have it exit the soil into the air
above the turf.

34. Air Quality
• Large fans installed to provide good air circulation and
lessen humidity and disease.

35. Air Quality
Wind
• cools grass blades
• increases transpiration from the leaves
• enhances CO2 exchange
• Causes abrasive action by sand
• Drys seedlings
• Salt spray near oceans
• Weed seeds and disease spores brought in

36. Air Quality
Pollution
• Natural - dust, sea salt, smoke
• Smog (less common in US due to improved
improved air quality)
• oily appearance to the leaves
• bleaching or banding of the leaves
• sulfur dioxide SO2
• from burning coal and oil.
• fluorides (HF and/or SiF4)
• around high industrial areas

37. Turfgrass Wear
• Direct pressure causing crushing of leaves, stems,
and crowns.
• Scuffing which causes tearing of leaves.

38. Turfgrass Wear
• Damage is lessened if turfgrass plants have:
• tough, coarse stems
• tough, veiny leaves
• high shoot density
• adequate leaf moisture levels
1. Zoysia
2. Bermuda
3. Tall Fescue
4. Paspalumgrass

39. Turfgrass Wear
• healthy turf is more tolerant to wear
• keep turf properly fed and watered
• higher cutting heights are more tolerant to wear
• more blades distribute the load better
• more thatch aids in wear tolerance
• high nitrogen levels lessen wear tolerance
• turf blades are more succulent.
• young seedlings are less tolerant to wear
• keep traffic off of young lawns until well established
• increased potassium aids in wear tolerance
• toughens cell walls.

40. Turfgrass Wear
Environment
• Low light levels reduces wear tolerance due to
elongated leaf blades
• Consistent lack of watering increases wear injury
• Frosted leaves are crushed when stepped on
It may better to just put in a sidewalk or to redirect
the traffic pattern.

41. Soil Compaction
Soil compaction is the pressing together of soil particles
into a more dense soil mass.
• less oxygen and carbon dioxide exchange
• poor water infiltration
• restricted root growth

42. Damage and Removal
• Golf Divots
• depends on player, type of turf,
and cutting height
• rate of repair depends on type
of turf (bunch, stolons,
rhizomes) and whether the
divot is filled in with the
removed sod or sanded in.
• Ball marks - golfers must
repair them!

43. Damage and Removal
Turfgrass Damage Due to Vehicles on Wet Soil
Foot divots - usually on soggy turf on athletic
fields
Tire ruts - on soggy turf or under constant
traffic