Test 1 Flashcards
4 reasons Turf grasses are important:
- Provide food.
- Stabilize various environments
- Furnish large group of ornamental grasses.
- Provide the major plants used as turf in lawns,parks, etc.
Turf grasses belong to what family?
how many genera? Species?
Poaceae or Gramineae
600 g, 7,500 species
150 g in us, 1,500 sp. in us
over 100 cultivars for turf managers to select.
What climate zone is Tn in?
Transitional, bermuda, zoysiagrass, tall fescue.
Name grasses in each zone:
Cool Humid:
Warm Humid:
Hot Humid:
CH: bluegrass, fine fescue, tall fescue, ryegrass
WH: Bermuda, zoysiagrass, centipedegrass.
HH: Bermuda, Zoy, centipede, carpet, bahiagrass, seashore paspalum
Describe BermudaGrass:
Cynodon spp.
from: eastern africa to east indies, 1751
9 species chromosomal #s 18-54
advantages of bermuda8:
.5 to 1.5 in cut- low cut height good traffic tolerance drought tolerance rapid recovery times- rhizomes and stolons uses 68% less water than cool season. ph tolerant 5.5-8.5 utilization of effulent water. pesticide and growth regulatory tolerance and disease resistance.
disadvantages of bermuda:
goes dormant when temps fall below 50 degrees
high N reqs .5- 2 lbs N/1000 sq.ft. per gorwing month
encroachment into other grasses.
thatch/mat producing
winter kill potiential
poor shade tolerance
unstable genetics
Scientific names and description of Common bermudagerass:
two cultivars?
C: Cynodon dactylon- 36 chromosomes, medium coarse/density, unsightly seed heads. use in roughs/ball fields. lawns. tetrapolid
seed head 3-5 spikelike racemes.
Yukon and Riveria- more cold tolerant.
Scientific names and description of hybrid bermudagerass:
H: Magennis bermudagrass, (C.Dactylon x C.Transvaalensis)- 27 chromosomes, triploid -Better disease resistance, - finer texture and darker color -tighter density -no viable seed Tiffgreen(328)-- TifWay(419)---TifSport
Ultra dwarf from location: benefits?
Texas-
Carolina-
Hawaii-
Champion
carolina
Hawaii
can be mowed under .187 to .1’’
Characteristics of ultradwarfs-
higher shoot-leaf density
slow vertical growth
increased stoloniferious growth compared to rhizomes
needs intense grooming and mowing less than 3/16’’
Bermudagrasses from Kansas state-
why?
Midfield, Midiron, Midlawn, Midway
shade/ cold tolerance
Zoysiagrass advantages
Best cold tolerance of warm season, good cold,shade, and salt tolerance slowgrowing tolerates moist soils medium to fine texture,wear resistance very dense and prevents weeds.
Zoysiagrass disadvantages-
medium to high matinence needs reel mower heavy thatch poor drought tolerance slow establishment nematode, brown patch, and dollarspot susceptible.
Zoysiagrass manilagrass-
Zoysia matrella fine leaf high matinence less cold hardy diamond, Zeon- putting green
Hybrid Zoysiagrass-
Zoysia japonica x Z. tenuifolia
good shade, dark green
high maint, thatch
Emerald.
Bahiagrass-
3 advantage-
4 disadvantages
Paspalum notatum - v shaped seed head.
- drought tolerant
- deep rooting
- tolerant of dry,sandy soils
- difficult to mow- tough seed stalks
- coarse texture
- poor salt tolerance
- mole cricket damage
Centipedegrass-
3 adv.
4 dis.
Eremochloa ophiuroides ph 5.5, acidic soils 1.seeded or sodded 2.low maintence 3.slow growth 1. poor drought tolerance 2. Iron deficiency sensitive 3. range limited by cold tolerance. 4. stolon growth only
St. Augustinegrass
3 adv.
3 dis.
Stenotaphrum secundatum 1. adapted to alkaline, sandy soils 2. shade and salt tolerant 3. dark green color/dense sod w/ good appearance. 1.Coarse texture 2. cold and traffic wear sensitive 3. sensitive to many herbicides. pest problems. raleigh- shade/cold/chinchbug
Creeping Bentgrass-
Cool season grass, (C3) Stoloniferous fine textured year round green color, superior playing surface.
causes of bentgrass decline 6-
Heat mowing/scalping humidity shade salinity air circulation
Cool season vs. Warm season-
Air temps-
Soil temps-
Cool- 60-75 Warm- 80-95
Soil-50-65 75-85
Tall fescue-
advantages
Testuca arundinacea
- year round color w/ irrigation
- established by seed/ sod
- wear resistant
- Endophytic fungi for insect bio-control
- low fert req.
tall fescue disadvantages-
- summer irrigation needed.
- bunch type growth
- goes semi-dormant during summer
- brownpatch disease.
- white grub susceptible
Kentucky Bluegrass-
4 adv.-
Poa pratensis cool season- most widely used vigorous rhizome system 1. year round color- when irrigated 2.established by seed or sod. 3.fine to coarse texture 4. better cold tolerance than ryegrass or tall fescue.
Ky Bluegrass dis adv.
- summer irrigation needed
- semi dormant in summer
- thatch problems
- not tolerant to close mowing heights
- diseases- rust and leaf spot.
Perennial Ryegrass
3 adv-
Lolium perenne-
short lived, medium texture,
1.fast establishment
2.tolerates lower mowing height than kyb or tF
3. Used to overseed bermuda tees/ fairways.
Rerennial Ryegrass disadv. 3-
- doesnt tolerate drought
- doesnt tolerate extreme temps
- thin or damaged areas must be reseeded.
Annual BlueGrass-
Rough stalk Bluegrass-
Poa Annua -weed in some areas prolific seed heads -tolerates close mowing -poor heat/disease tolerance
Poa trivialis-bright green, bremuda overseed
Seashore Paspalum-
Paspalum vaginatum -Salt tolerance -Argentina -poor herbicide tolerance/cold tolerance SeaIsle 2000
Seashore Paspalum ADV
Salt tolerance to 34,500ppm low fert req great drought tolerance Strips easily Good playability
Seashore paspalum Limitations-
Lack of selective bermudagrass control minimal shade tolerance limited cold tolerance slower green up than warm season- 2 weeks later seedheads/thatch
How much rain do we normally get :
50-65 inches
Buffalograss-
low maintenance,
10-25 inches of rain yeaarly
stolons and seeds(burs)
Buffalograss adv-
low main, water/fert needs
deep rooted, good drought tolerance
seeds available
tolerates soil textures and pHs, prefers alkaline soil
Buffalo Dis-
Cold ,
rainfall over 25 in
goes dormant during drought
thin open growth
Native Warm season grasses-
Big bluestem- 6ft
Little Bluestem- 2ft
Broomsedge
Weeping love grass-2ft
Switchgrass
Indiangrass
Other cool season grasses
Orchardgrass
Timothy
Blue Fescue
Junegrass
-use a mix
Study of plant germination growth and development.
What 3 processes does this include
Plant Physiology
Photosynthesis, Transpiration, Resipation
Describe which processes cool season grasses and warm season grasses undergo during the Winter and summer:
Winter cool- Photosynthesis/ Summer cool- Respiration
Winter warm- Respiration /Summer warm- Photosynthesis
Describe Photosynthesis-
Light is converted into usable energy(carbohydrates)
produces O2
occurs in chloroplasts
Light reaction- thylakoid membrae
Dark Reaction- Stroma
Light reactions produce ATP and NADPH, which enter the calvin cycle and become NADP, ADP that go back to light reactions. Calvin cycle produces Glucose.
What is a stack of thylakoids-
Granum
What wavelenghts are photosynthetically active radiation?
WHat colors do plants absorb-
380-775
red and blue, mostly red=low energy= easier to process
Bermuda needs 8 hours min
Name the light absorbing pigments-
Chlorophyll a and b(green)
Carotenoid(light yellow to orange) less but broaden spectrum.
Describe the Calvin Cycle-
Transmission of electrons in the stroma to produce glucose.
Describe the cycle used by cool season grasses-
C3 cycle
- forms 3 carbon sugar or 3-PGA
- 6 carbon sugar for sucrose, starch, cellulose
- ADP AND NADP are cycled back to light portion.
6CO2 +12NADPH+12H+18ATP+H20= C6H1202+17Pi+18ADP+12NADP
Describe the cycle used by warm season grasses-
C4 cycle
- 4 carbon sugar (OAA)-
- glucose used for starch and sucrose
- Needs higher temps and light intensities.
C3 plants:
leaf anatomy-
large are spaces and less CO2 conc.
Optimum temp=59-77
not as efficient.
Have RuBP carboxylase- which is sensitive to CO2 and 02
C4 plants
Leaf anatomy-
optimum temps-
Krans anatomy- mesophyll around bundle sheath cells, concentrates CO2
temps= 85-117
Has PEP carboxylase only sensitive to CO2, more efficient
Compare C4 to C3-
In C4 leaf veins are closer together and surrounded by a layer of bundle sheath cells. less airspace= higher concentration of CO2 and more efficiency.
C4 plants have smaller stomal openings, thus less water loss.
C4 less overall N content. =use N more efficiently
Reversal of photosynthesis where sugars and staches are synthesized for plant energy-
describe when warm and cool season do these-
Respiration
Glycolysis+ Krebs Cycle+ Oxidative Phosphorylation
warm: spring and fall when less light is available.
cool-during the summer to fight heat when stoma are closed.
After two turns the end result is a net sum of 36 ATP
Describe photorespiration between C4 and C3 plants-
on bright, hot, dry days C3 plants reduce transpiration by closing the stomates so CO2 levels drop and O2 levels increase.
temps rise, c3 plant lose efficiency because faster CO2 loss by photorespiration.
stomates must open to allow more CO2 but then plant loses water.
C4 plants lose less water per unit of CO2
Describe growth patter of warm vs cool season:
Warm peak in summer
Cool peak in Spring and Fall (spring slightly higher)
fert cool season 1 lb in spring, 2 lbs in fall
a group of cells which are able to divide and enlarge-
where are these located in grasses-
meristems
top of crown
intercalary meristem- between leaf blade and sheath
roots that develop out of the crown-
describe the primary root-
what do roots need?
Adventitious
a root that develops out of the seed then withers.
oxygen for respiration
roots are the immune system of the plant.
Rooting: Optimum soil temps- Soil pH- Nutrients- Light-
warm-75-85 / cool 50-65
pH 5.0- 8.0
K, P, Fe, Ca
shade discourages deep rooting.
Which type of grass have larger root diameters and greater rooting depth?
Warm,
total length, number of root hairs, total surface area
What do roots need from shoots?
What do shoots need from roots?
When is shoot growth favored over root growth(3)
roots need carbohydrates, shoots need water and minerals
soil temps above optimum, close mowing height,(less Ps)
Low light conditions(less Ps = less carbohydrates)
the process of a turfgrass producing new stems and leaves? few factors that promote this-
Tillering
shade increase, morderant N levels, Longer days, decreases as soil dries.
Max soil temp for root growth in cool season-
70-75
Max Air temp and Soil temp for Suggested planting
Cool Air-75-80, Soil 60-70/ Warm Air-80-90 Soil 70-80
Max Air temp for shoot growth-
Cool Air-60-75 /Warm Air 80-95
Max Soil temp for root growth-
Cool- 50-65/ Warm 75-85
What Warm season grass is the most cold tolerant-
buffalograss, zoysia in the south-east
Name some reason Low Temps kill Turf(9)
Excessive traffic- crush frozen crowns Moisture- to much or to little potassium deficiency- health element Excessive fall nitrogen fert: want 4-1-2 Wind w/ low humidity close mowing shade cultivar pest/pesticide damage.
What makes better cold tolerance-
greater number of proteins and sterals= better cold tolerance.
What causes bentgrass decline-
bad management practices, shade, salinity,compacted soils.
First thing to do if plant stress is noticed-
raise mowing heights.
What are the growth promoting Horomones-
Auxin- meristematic tissue
Gibberillins,- roots/leaves/meristematic tissue/seeds.
Cytokinis- root tips (cytokinesis)
cell elongation and cell division.
Growth inhibiting horomones-
Ethylene- shoots, plant ageing
Absistic acid- green tissue(chloroplasts),
Any material that stimulates life-
Biostimulant , do not mix with growth regulators
most consistent in sand based soils, stress periods, most have GA or cytokinins and N, Fe,
What do excessive levels of growth horomones do?
Inhibit growth or cause imbalance and affects normal growth and development.
What equals soil Fertility-
CEC= total number of exchange sites on surfaces of clay or organic matter. Cations Adsorb onto sites.
CEC=
H+Al+Ca+Mg+K+Na in meq/100g of soil
left to right strongest to weakest.
What two forms of N can plants take up?
NO3 and NH4
Base Saturation =
Ca+Mg+K+Na/ CEC
as BS increases soil pH and fertility increase
higher BS ease cation absorption by plants
Breakdown of large particles and replacement of strong positives with weaker positives creates a strong negative charge overall-
Isomorphous Substitution
Describe characteristics of Cations-
What are the basic cations and their charges-
Smaller cations have greater affinity than larger, mass.
cations with higher charge are held over lower ones.
Ca=+2 Mg=+2 K=+1 Na=+1
stable highly broken down organic matter-
hummus
CEC of Sand vs Sandy loam-
sand- 0-6
sandy loam =6-12
What BS do most turf managers want?
what is available at high and low pH
60%
High pH Macro
Low pH micro
In acidic soils, what cations suppress the others
H+ and Al+++ suppress Ca++ and Mg++
Desired percentages of Cations in Cec and Bs
Ca:60-70 / 50-80 Ca for Bs
Mg:10-20/ 8-22 for BS
K:5-10 / 3-6 for Bs
Na 0-1/ 0-1
Exchangable Acidity=
H+ Al/Cec
Active Acidity-
The dissociated H ions floating in the soil solution.
= H+
Reserve acidity-
the measurement of ions still attached to the surface of the clay or OM. buffer capacity, exchangeable acidity, or potential acidity.
H+AL
What makes a strong acid a strong acid-
it dissociates completely
What happens as soil pH increases-
Al ions precipitate leaving negative charges allowing other cations to be retained.
A one point change in pH is equal to what change in H+ concentration?
10x
Ideal soil pH
5.5 to 6.5
Liming materials to raise pH
Calcite -CaCO3 Dolomite- CaMg(CO3)2 Calcium Oxide- CaO burned Calcium Hydroxide- Ca(OH)2 use prior to planting Liquid lime- not affordable
Most popular is pelletized Limestone
How do you calculate liming rate?
Active pH + Buffer pH
clay requires higher rate but sand requires more frequent apps.
Applying more than 50-100 lbs/ sq.ft. at once may cause burn.
if hydrated or burned use less and 25lbs/1000
what do you use to supply calcium or Mg and not affect soil pH?
Gypsum
What kind of areas typically have high soil alkalinity?
What are the best elements to use if high pH
low rainfall areas or coastal areas with natural high pH
elemental sulfur and aluminum sulfate needs help of thiobacillus spp to create sulfuric acid in the soil H2SO4
apply in spring/fall and till into top 6-8’’
Quick reduction of pH
Slow-
Elemental sulfur- needs freq apps 3-4 months appart.
Ammonia based products -NH4
do not apply more than 10lb/1000sqft yearly. High rates may encourage black layer.
Whats a way to reduce water pH?
Acid Injection, corrosive may damage irrigation parts
What % should a soil consist of?
50% solids, 25% air, 25% water and 3-5%OM
Gravel size
Silt size
Clay size
2mm
silt=.002mm
clay
Silt and Clay are determined by the rate of settling from suspension based on what law?
What method is used to determine this?
Stokes Law V=KD^2 K=10000
Hydrometer method
Concrete Sand-
Mason Sand-
More coarse particles, unstable if not enough fines
Usually screened concrete sand to remove gravel. prefered.
generally want 60% to be coarse or medium sand.
Particle Density-
mass of dry soil per unit volumer not including pores or water weight
2.65 g/cm average used.
Bulk Density-
Mass of dry soil per unit volume, including solids and pores. A measure of soil compaction. tends to be about half the particle density.
Higher # more particles per unit volume.
Ideal soil Bulk density for Golf greens?
1.2-1.6 g/cm^3 = 1.4 g/cm^3
bulk density and particle density is used to calculate?
soil porosity
Capillary-
Noncapilary-
smaller pores that determine a soils water content 15-25% golf greens
Macropores which determine air content -15-35% on gg.
balance of both is desirable ideal 25% for each.
rate at which water enters the soil surface?
speed that water moves through the soil profile
water flow through soil in relation to the amount of water
applied
How are these measured?
Infiltration rate
Percolation
Hydraulic conductivity
Darcys equation= K =Q/AT X dL/Dh
useing a double ring infiltrometer.
Darcy equation-
K= quanity of water divided by(Area times Time) X lenght of core times Head of water imposed.
Suggested guidelines for golf greens-
BD
Ksat-
Porosity
Bulk density- 1.4 g/cm
Ksat- 6-24 in/hr
Porosity- 35-55%
Typical USGA style profile-
16’’ total
12’’ rootzone mix
4’’ pea gravel layer
4’’ diameter round drain
the traditional style has a 2’’- 4’’ choker
Described Perched water-
Where the water reaches the bottom of the rootzone mix and will not drain into the gravel layer because of strong capillary action. Once the amount of water on top reaches a certain amount it can break the capillary action and push downwards into the gravel layer. If surface soil is dry water can be pulled towards the surface.
D85 describes what?
D15 describes what?
Largest 15% of sand particles
Smalles 15% of gravel size.
if gravel is to coarse sand can migrate “bridge” into the gravel.
USGA specifications create smaller voids and prevent migration of sand into gravel.
The USGA specs on sand and gravel-
D85- between .4 and .7 mm
D15
Gradation index-
what does interpacking sands do?
coefficient of uniformity , describes the uniformity of particle sizes thus predicts the potential of particle interpacking.
interpacking sands with a large graduation index reduces total pore space, reducing hydraulic conductivity
what was released in 1952 that is an F1 hybrid between a dense dwarf and disease resistant selection from pasture breeding program.
Tifflawn
Experimental name of Tiffine-
tiffton 27
Turfgrass research startion at Tifton,GA began what year?
1946
Experimental name fro tifgreen-
Tiffton 328
What was released in 1960 as a hybrid for fairways and athletic fields ,dark green color with frost tolerance
tiffton 419/ Tifway
What was discovered by USGA Agronomist Monty Moncrief as an offtype occuring on a putting green
TifDwarf
What type of zoysia is a cross of zoysia japonica and zoysia tenuifolia?
Emerald
Which is more variable, Soil Air or Surface Air?
What causes the variability?
What conditions make soils become anaerobic?
Soil are is much more variable
Soil moisture, temperature.
Roots uptake O2, the warmer the soil the faster it is taken up leaving CO2 into the soil, if the soil iv very moist it takes oxygen longer to defuse into the soil and the less oxygen the more anaerobic the conditions become.
Soils with highbulk densities or increased soil moisture where oxygen drops less than -10%
What are some toxic gasses that form in the soil
CO2, CH4, C2H4, N2, N2O, NO, NH3, H2S
How fast Does O2 diffuse through air compared to water?
10,000 times faster.
Explain what happens when soils do not have enough O2 in the soil.
Respiration decreases which decreases the amount of ATP in the plant, which leads to a lower cellular pH, that causes membrane deterioration or leaky membranes. Redox reactions also occur in the soil. When soil organisms cant get the O2 they need from the air they take it from other sources. NO3 becomes NH4,
Colors of good soils
Colors of bad soils
good soils are red, yellow, and redish brown- indicates well oxidized soils.
Bad soils are blues, greys ans black- low 02
Name two highly toxic substances formed in anaerobic soils-
sulfides and methane
Describe black layer-
formation of black layer beneath soil surface, smell from hydrogen sulfide, color from precipitation of metal sulfides. Needs lots of moisture and O2 for formation.
What happens when wetlands are drained?
ferrous sulfide is oxidized forming sulfuric acid and dropping the pH in the soil dramatically.
How is net heat of soil determined?
3 factors?
Rn=Rs - Rr - Rl Rn=net heat Rs=shortwave solar radiation Rr= reflected short wave Rl= reflected long wave infared
composition/color, moisture content/ cover
How does soil moisture affect heat
more moisture = more heat req.
heat retention capacity of water is 3-5x that for mineral soil
How does the heat lesson relate to bentgrass-
keep bentgrass soils as dry as possible during the summers and allow evaporative cooling at night to reduce heat load.
How does depth and surface affect soil heating up?
flat absorbs less heat as do south and SE facing soil.
Small microscopic organisms in soil-
Large
Bacteria, fungi, nematodes, algae, Actinomycetes,
Earthworms, insect larvae, mole crickets.
Producing organisms, use photosynthesis
Autotrophs, obtain carbon from CO2,
higher plants, algae and certain bacteria(thiobacillus spp.)
Consuming organisms-
Heterotrophs
bacteria, fungi, protozoa, animals
Describe Bacteria-
3 types-
Most abundant soil organism, no organelles
nitrification and nitrogen fixation.
Spheres (cocci) Ovals(spirals), rods(bacilli)
cynobacteria- chlorophyll, and fix N in damp conditions
Aerobes- require O2 for respiration,OM decomposers
Anaerobes- can use O2 from soil compounds
Name a bacteria species used as a biological control
Bacillus popillae
what is the only bacteria disease in turf
C-5 decline in creeping bentgrass.
Fungi-
2 important types
Multicellular organisms w/o chlorophyll,aerobic and heterotrophic, decomposers
can break down lignin and creates humus
mycorrhizae- provides symbiotic relationship with roots to aid in nutrient uptake like P
Endophytes-discourage certain foliage feeding
Algae-
Multicellular Aerobic and autotrophic Photosynthesis cyanobacteria- blue/green algae ph
Actinomycetes-
decomposers of cellulose and lignin , OM matter decomposers.
Prefer soil >= pH 5 most between 6.5-8
primitive bacteria with some fungi characteristics, single celled.
branched mycelia , second most abundant.
Important Actinomycetes-
Streptomyces spp. produce antibiotics, rich sweet smell in soil.
Benefits of soil Organisms -
Breakdown and recycle plant and animal residues with a corresponding release of water, heat, CO2, and nutrients.
Help form beneficial humus, breaksdown environmental pollutants, pesticides, and can be antagonistic against plant root pathogens
What convert N from organic matter to ammonium?
Ammonifiers
What convert ammonium to nitrite and nitrate?
Nitrifiers
long chain ploymer of glucose molecules
water insoluable polysaccharides mostly hexose and pentose sugars not structurally related to above
cellulose
hemicellulose (broken down faster and by wider arry of mO)
complex polymer of subunits of c6 -c3 material impregnating cell walls. whats this high in?
Lignin , turfgrass. thatch is caused by this because my soil microorganisms cant break this down.
stable dark colored, final product of OM decomposition
humus.
What is the desired C:N rate?
what controls the rate of OM decomposition?
10:1
amount of available N
if a soil amendment has a high ratio then N additive will need to be put down with it because bacteria will consume the N and plants wont receive it.
When does Denitrification occur and what is it?
under wet conditions, where N2 is converted into gaseous N2.
What is enhanced Biodegration-
where fungi and bacteria become efficient at breaking down chemicals.
What is microbial Innoculation?
Adding soil organisms (mostly bacteria) to golf greens
needs to be done directly to the soil surface,because uv sensitive. may out compete naturally occurring beneficial microbes. unknown field of study.
Sand Sizes and Seive no.
V.Coarse=1-2 18 Coarse=.5-1 35 Medium= .25- .5 60 fine= .1- .25 140 Vfine= .05-.10 270
