The Atmospheric Environment
Jan 11, 2016
The Atmospheric EnvironmentThe Atmospheric Environment
Atmospheric EnvironmentAtmospheric Environment
MacroenvironmentMacroenvironment - up to 5 ft above the - up to 5 ft above the ground, representative of the overall climateground, representative of the overall climate
MicroenvironmentMicroenvironment - immediate vicinity of - immediate vicinity of the turfgrass plant, ranging from the canopy the turfgrass plant, ranging from the canopy surface to the bottom of the rootzonesurface to the bottom of the rootzone
ClimateClimate
LightLight TemperatureTemperature MoistureMoisture WindWind Relative HumidityRelative Humidity
Light AbsorptionLight Absorption
Vital to lifeVital to life Affected by mowing, leaf areaAffected by mowing, leaf area Affected by leaf angleAffected by leaf angle Influenced by surroundingsInfluenced by surroundings
cloudsclouds buildingsbuildings treestrees Clippings - light exclusion!Clippings - light exclusion!
The Fate of Solar RadiationThe Fate of Solar Radiation
ReradiationReflection Absorption (heat)
Transmission
Absorption (chemical)
Light QualityLight Quality
Visible Spectrum
InfraredUltra-violet
400 nm 700 nm
Light QualityLight Quality
Visible Spectrum
InfraredUltra-violet
Photosynthesishas two peaks inthe visible range
Light Duration Affects Form of Cool Season Grasses
Light Duration Affects Form of Cool Season Grasses
Short days (spring and fall) affect:Short days (spring and fall) affect: increased densityincreased density greater tillering/stolons/rhizomesgreater tillering/stolons/rhizomes shorter leavesshorter leaves more leavesmore leaves smaller shootssmaller shoots more prostrate growth habitmore prostrate growth habit
Opposite occurs in long days of summerOpposite occurs in long days of summer
Light IntensityLight Intensity
Seasonal Seasonal LatitudeLatitude Time of dayTime of day Atmospheric screeningAtmospheric screening TopographyTopography
Sufficient Light Intensity is required to sustain adequate
photosynthesis and thus growth.
All turfgrasses prefer to grow in full sunlight.
Sufficient Light Intensity is required to sustain adequate
photosynthesis and thus growth.
All turfgrasses prefer to grow in full sunlight.
Three Components of Photosynthesis:Three Components of Photosynthesis: Compensation point - where the light level Compensation point - where the light level
is low and just adequate to produce enough is low and just adequate to produce enough photosynthesis to match respiration. The photosynthesis to match respiration. The net gain of carbon is net gain of carbon is zerozero..
Intermediate light levels produce enough Intermediate light levels produce enough carbohydrates to compensate for nighttime carbohydrates to compensate for nighttime respiration, plus enough extra to support respiration, plus enough extra to support new growth and sustain tissuenew growth and sustain tissue
Three Components of Photosynthesis:Three Components of Photosynthesis: High light, where photosynthesis is high High light, where photosynthesis is high
enough to produce extra carbohydrate that enough to produce extra carbohydrate that can be stored. Excessively high light may can be stored. Excessively high light may be damagingbe damaging
Temperature and other stresses can affect the Temperature and other stresses can affect the ability of a turf to effectively utilize higher ability of a turf to effectively utilize higher light levels light levels
Photosynthetic Light CurvePhotosynthetic Light CurveP
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Light Level
0
Low Medium Full Sun
Carbohydrate Storage
Maintenance
Compensation Point
Inhibition
Physiological Responses to Low LightPhysiological Responses to Low Light Higher chlorophyll contentHigher chlorophyll content Lower respirationLower respiration Lower compensation pointLower compensation point Reduced carbohydrate reservesReduced carbohydrate reserves Lower demand for water, nutrientsLower demand for water, nutrients Reduced heat, cold, drought, wear toleranceReduced heat, cold, drought, wear tolerance
Photosynthetic Light CurvePhotosynthetic Light CurveP
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Light Level
0
Low Medium Full Sun
Shade-adapted Sun-adapted
Developmental Responses to Low LightDevelopmental Responses to Low Light Reduced growthReduced growth Thinner leavesThinner leaves Reduced shoot density; Reduced tilleringReduced shoot density; Reduced tillering Longer, more erect leavesLonger, more erect leaves Leaves are more succulent (less substance)Leaves are more succulent (less substance) Longer internodesLonger internodes Slower establishmentSlower establishment
Shade Increases DiseaseShade Increases Disease
Thinner leaves less resistantThinner leaves less resistant Sun inhibits spore germinationSun inhibits spore germination Higher humidity increases spore Higher humidity increases spore
germinationgermination
Shade is not just Reduced LightShade is not just Reduced Light Light quality can change as it passes through Light quality can change as it passes through
the tree canopy. The tree leaves “remove” the tree canopy. The tree leaves “remove” the red and blue light components, leaving the red and blue light components, leaving mainly the green, which is not effective in mainly the green, which is not effective in photosynthesisphotosynthesis
Shade moderates air temperaturesShade moderates air temperatures Shade is associated with increased humidity, Shade is associated with increased humidity,
which may increase heat load, diseaseswhich may increase heat load, diseases
Shade from Trees:Shade from Trees:
Tree roots compete for water and nutrients. Tree roots compete for water and nutrients. Where are the tree roots?Where are the tree roots?
Deciduous trees present extra problem in Deciduous trees present extra problem in fall when leaves are shed. This can lead to fall when leaves are shed. This can lead to extreme light exclusion. How to handle?extreme light exclusion. How to handle?
AllelopathyAllelopathy - some tree roots exude specific - some tree roots exude specific chemicals which interfere with turf growthchemicals which interfere with turf growth
Best Species for Shade ToleranceBest Species for Shade Tolerance
Cool SeasonCool Season Tall fescueTall fescue Fine fescuesFine fescues BentgrassBentgrass
Warm SeasonWarm Season St. AugustineSt. Augustine ZoysiaZoysia CentipedeCentipede
Managing for ShadeManaging for Shade Thin tree canopy. Also increases wind, reduces Thin tree canopy. Also increases wind, reduces
humidityhumidity Raise cutting heightRaise cutting height Reduce N fertilityReduce N fertility Irrigate deeply, infrequentlyIrrigate deeply, infrequently Control trafficControl traffic Fungicides to control diseaseFungicides to control disease Fertilize tree roots separatelyFertilize tree roots separately
TemperatureTemperature
The most important environmental factor The most important environmental factor affecting the adaptation of turfgrasses to a affecting the adaptation of turfgrasses to a particular geographic region. particular geographic region.
Growth generally confined to > 40Growth generally confined to > 40oo, < 105, < 105o o FF Temperatures fluctuate depending on the Temperatures fluctuate depending on the
amount of energy received from the sunamount of energy received from the sun
Heat can be Transferred from One Environmental Component
to Another
Heat can be Transferred from One Environmental Component
to Another EvaporationEvaporation ReradiationReradiation ConductionConduction ConvectionConvection AdvectionAdvection
Turf Modifies TemperaturesTurf Modifies Temperatures Temperature extremes much less with turf Temperature extremes much less with turf
surface than with bare soil, pavingsurface than with bare soil, paving Turf absorbs a substantial amount of energyTurf absorbs a substantial amount of energy Much of the energy is dissipated by one of the Much of the energy is dissipated by one of the
transfer processes. The most important is transfer processes. The most important is evapotranspirationevapotranspiration (ET, total loss of water (ET, total loss of water from turf and soil surface). from turf and soil surface).
Turf Modifies TemperaturesTurf Modifies Temperatures Evaporation requires large input of energy, Evaporation requires large input of energy,
which is “used up” by converting water from which is “used up” by converting water from liquid to gas. This is called the liquid to gas. This is called the latent heat of latent heat of evaporationevaporation
Where does the heat come from to evaporate Where does the heat come from to evaporate the water? From the turfgrass plant and the water? From the turfgrass plant and surroundings.surroundings.
Turf Response to TemperatureTurf Response to Temperature
MinimumMinimum MaximumMaximum OptimumOptimum
60-75 60-75 oo for cool season shoot growth for cool season shoot growth 80-95 80-95 o o for warm season shoot growthfor warm season shoot growth
Root growth can continue as long as soil Root growth can continue as long as soil temperatures are favorabletemperatures are favorable 50-65 50-65 o o for cool seasonfor cool season 75-85 75-85 oo for warm season for warm season
Temperature Effects on RootsTemperature Effects on Roots
Optimum temperatures produce white, long, Optimum temperatures produce white, long, multi-branched rootsmulti-branched roots
Sub-optimal temperatures produce white, Sub-optimal temperatures produce white, shorter, slower growing, less branched rootsshorter, slower growing, less branched roots
Supra-optimal temperatures produce roots Supra-optimal temperatures produce roots that become brown, spindly, mature rapidly, that become brown, spindly, mature rapidly, die faster, and aren’t replaced as fast.die faster, and aren’t replaced as fast.
High Temperature Stress(often associated with drought stress)High Temperature Stress
(often associated with drought stress) Indirect:Indirect:
rapid turnover of roots, resulting in loss of root systemrapid turnover of roots, resulting in loss of root system decrease in shoot growth, perhaps due to reduction in decrease in shoot growth, perhaps due to reduction in
photosynthesis, carbohydrates. May lead to summer photosynthesis, carbohydrates. May lead to summer dormancydormancy
Direct:Direct: High temps can kill turf. High temps can kill turf. Crown, young leaf, apical meristem are more tolerant Crown, young leaf, apical meristem are more tolerant
than older tissuethan older tissue
Heat Hardiness of CS TurfgrassesHeat Hardiness of CS Turfgrasses
Tall Fescue, Creeping BentTall Fescue, Creeping Bent
Kentucky BluegrassKentucky Bluegrass
Fine FescuesFine Fescues
Perennial RyegrassPerennial Ryegrass
Annual RyegrassAnnual Ryegrass
Highest
Lowest
Low Temperature StressLow Temperature Stress
Direct stress: when the liquid inside the cell Direct stress: when the liquid inside the cell freezes. Cells may rupture, proteins denature. freezes. Cells may rupture, proteins denature. Depends on level of tissue hydration Depends on level of tissue hydration Prevent by correcting compacted soilsPrevent by correcting compacted soils Avoid excessive fall nitrogenAvoid excessive fall nitrogen Maintain adequate potassium, phosphorusMaintain adequate potassium, phosphorus Minimize thatch accumulationMinimize thatch accumulation
Aerial ComponentsAerial Components COCO2 2 and Oand O22 are important in the plant and in the are important in the plant and in the
soil. Low levels of COsoil. Low levels of CO22 in the plant will limit in the plant will limit
photosynthesis. Low levels of Ophotosynthesis. Low levels of O22 in the soil limit in the soil limit
root respiration and thus root function. When root respiration and thus root function. When does soil Odoes soil O22 become a problem? become a problem? When soils are warm and microbial respiration is highWhen soils are warm and microbial respiration is high During flooding or pondingDuring flooding or ponding When surface is sealed, diffusion is lowWhen surface is sealed, diffusion is low
WindWind
Evaporative coolingEvaporative cooling Increases ET, evapotranspirationIncreases ET, evapotranspiration Deposits soil, sand, snow, seeds, pollen, Deposits soil, sand, snow, seeds, pollen,
spores spores Wind-blown sand as abrasiveWind-blown sand as abrasive Enhances COEnhances CO2 2 exchange. How?exchange. How?
The Atmosphere: approx. 360 CO2 molecules per 1 million total gas molecules
The Atmosphere: approx. 360 CO2 molecules per 1 million total gas molecules
Stomates on a Leaf SurfaceStomates on a Leaf Surface
Stomate Opening
StomatalCavity
Epidermal cells
Wind keeps CO2 replenished
Stomate Opening
StomatalCavity
Epidermal cells
“Dead” Air Becomes Depleted of CO2
Sources/Forms of WaterSources/Forms of Water
PrecipitationPrecipitation IrrigationIrrigation Dew and guttationDew and guttation Gaseous - Relative HumidityGaseous - Relative Humidity
Dew and GuttationDew and Guttation
Dew is condensation caused by differences Dew is condensation caused by differences in temperature between air and a surface. in temperature between air and a surface. How does this happen in turf?How does this happen in turf?
Guttation occurs when the plant absorbs Guttation occurs when the plant absorbs more water from the soil than it loses more water from the soil than it loses through the stomates. The excess is exuded through the stomates. The excess is exuded through cut leaf ends or through special through cut leaf ends or through special pores called hydathodes, at the leaf tipspores called hydathodes, at the leaf tips
GuttationGuttation
Occurs at night, shortly after fertilizing with Occurs at night, shortly after fertilizing with soluble N fertilizers and with frequent soluble N fertilizers and with frequent irrigationirrigation
Liquid contains sugars, salts, amino acids, a Liquid contains sugars, salts, amino acids, a perfect growth medium for pathogensperfect growth medium for pathogens
Guttation is removed to reduce disease and Guttation is removed to reduce disease and to improve mowing quality, reduce to improve mowing quality, reduce clippings from clumpingclippings from clumping
Relative HumidityRelative Humidity
Can influence night temperature. High Can influence night temperature. High humidity reduces long wave reradiation, humidity reduces long wave reradiation, which keeps surfaces warmer. Desert turf which keeps surfaces warmer. Desert turf cools off at night due to low humidity, cools off at night due to low humidity, permits CS turf to be grown in very hot permits CS turf to be grown in very hot climates. climates.
Controls the amount of dewControls the amount of dew Partly controls evaporative coolingPartly controls evaporative cooling