Turfgrass management and culture


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Turfgrass management and culture

  1. 1. Turfgrass Management and Culture Jason Kruse, Ph.D.
  2. 2. Scope of the Turfgrass Industry• Value added by the turfgrass industry – 1982 Study estimated that the industry was valued at $25 billion.• At that time, Florida turfgrass industry estimated to be $1.1 billion.• Currently: – Florida is #1 in US with 3.94 million acres – Total revenues for Florida estimated at $7.82 billion in 2007 – Total employment of 173,166 jobs
  3. 3. Florida Golf Course Revenues 2007 Total revenues $4.06 billion Average revenue per firm: $4.4 million Other Lodging Recreation Other 2% Retail 3%Food/Beverage 2% 17% 11% Golf 65%
  4. 4. Turfgrass ManagementGolf Course Management
  5. 5. Turfgrass ManagementGolf Course Construction
  6. 6. Turfgrass Management Sports Turf Management
  7. 7. Turfgrass Management Sports Turf Management
  8. 8. Careers in Turfgrass Management Professional Landscape Management
  9. 9. Turfgrass ManagementProfessional Landscape Management
  10. 10. Careers in Turfgrass Management Sod Production
  11. 11. Careers in Turfgrass Management University Researcher
  12. 12. Turfgrass 101• Identification of common warm-season turfgrasses• Establishment• Cultivation/Mowing• Fertilization• Weeds/weed control
  13. 13. Bermudagrass• Hybrid Bermudagrass (Cynodon dactylon X C. transvaalensis) – Description: Originated in eastern Africa in 1751 or earlier; sometimes called devil grass; stolons and rhizomes; vernation - folded; ligule - fringe of hairs; auricles - absent; collar - narrow, continuous, hairy on margins; blade - smooth or hairy on both surfaces, tapers toward the tip; inflorescence - four or five spiked branches. 14
  14. 14. Zoysiagrass Bermudagrass 15
  15. 15. St. Augustinegrass Stenotaphrum secundatum [Walt.] Kuntze.• Identification – VERNATION: folded – LIGULE: fringe of hairs, 0.3 mm long – SHEATH: – AURICLE: absent – COLLAR: broad, continuous, narrow to form a short stalk at the base of the blade. – LEAF BLADE: flat, 4 - 10 mm wide, smooth on both surfaces, with a blunt tip, 90-degree angle from sheath at the collar. – GROWTH HABIT: stoloniferous. 16
  16. 16. St. AugustinegrassStenotaphrum secundatum [Walt.] Kuntze.) 17
  17. 17. Japanese Lawngrass• Zoysia japonica Steud. Identification – VERNATION: rolled – LIGULE: fringe of hairs, 0.2 mm long – SHEATH: short, flat, smooth – AURICLE: absent – COLLAR: broad, continuous, with long hairs. – LEAF BLADE: flat, 2 - 4 mm wide, stiff, long hairs distributed along smooth adaxial and, sometimes, abaxial surfaces, sharply pointed. – GROWTH HABIT: rhizomatous & stoloniferous (stolons with husk like sheaths. 18
  18. 18. Japanese LawngrassZoysia japonica Steud. 19
  19. 19. Bahiagrass Paspalum notatum Flugge• Identification – VERNATION: rolled or folded – LIGULE: membranous – SHEATH: compressed, split – AURICLE: absent – COLLAR: broad – LEAF BLADE: flat to folded, 4 - 8 mm wide, margins sparsely hairy toward base. – GROWTH HABIT: rhizomatous & stoloniferous 20
  20. 20. BahiagrassPaspalum notatum Flugge 21
  21. 21. Seashore Paspalum Paspalum vaginatum Swartz.• Identification – VERNATION: rolled – LIGULE: membranous, 2-3 mm long, pointed. – AURICLE: absent – COLLAR: broad, continuous – LEAF BLADE: flat with margins rolled inward, 2 – 4 mm wide, margins sparsely hairy toward base. – GROWTH HABIT: rhizomatous & stoloniferous 22
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  23. 23. MowingMowing is the periodic removal of part of the turfgrass shoot. 24
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  30. 30. Mowing Equipment – Reel Mowers• Best for highest turf quality because of its scissor-like cutting action.• Consists of a rotating reel cylinder equipped with blades and a stationary bedknife. 31
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  33. 33. Mowing Equipment – Rotary Mowers• A horizontal blade cuts the grass blade by impact.• Does not produce as sharp a cut as a reel mower, but is acceptable for turfs cut above 1".• Most dangerous turf equipment at home. 34
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  36. 36. Mowing Equipment – Rotary Mowers Keep blades sharp and balanced.  Dull blades tear instead of cutting cleanly which exposes more tissue to drying and takes turf longer to recover. Mow parallel on slopes - not up and down. Clean area of trash and debris before attempting to mow. Observe all safety precautions - keep hands and feet clear. Do not mow wet, tall grass. 37
  37. 37. Mowing Equipment – Sickle Bar• Sickle Mowers Mowers – For haying operations. – Used on tall grass, mainly on roadsides. 38
  38. 38. Mowing Equipment - Flail Mowers• Vertical rotation but safer than horizontal rotary because of free swinging blades. 39
  39. 39. Mowing• Most basic, yet most important cultural practice that can be used to provide desirable turf.• Turfgrasses can be mowed close to the ground due to the terminal growing point (crown) being located at or just below the soil surface. – Regrowth from cell division and elongation takes place below the height of the mower blade. 40
  40. 40. Mowing• Turfgrass growth habit is affected by mowing. – Frequent mowing increases tillering and shoot density. – Mowing decreases root and rhizome growth because food reserves, following mowing, are utilized for new shoot tissue development at the expense of root and rhizome growth. • Improper mowing exacerbates the problem 41
  41. 41. Mowing is a STRESS• Effects of Mowing – Water loss – Disease Development – Decreased Carbohydrate Storage – Increased Shoot Density – Small Shoots – Decreased Root and Rhizome Growth 42
  42. 42. Variables Influencing Mowing Height• Species/Cultivar – Each turfgrass species has an adapted range in which it tolerates mowing. • This range will be lower than the recommended mowing height . –Mowing below the recommended mowing height, but within the range of tolerance, requires a higher level of maintenance to maintain a healthy turfgrass stand. 43
  43. 43. Variables Influencing Mowing Height• Species/Cultivar (cont.) – Mowing below the tolerance range will result in rapid deterioration of turfgrass quality. • Excessively close mowing heights will decrease the: –total leaf area –carbohydrate reserves –root growth 44
  44. 44. Variables Influencing Mowing Height• Species/Cultivar (cont.) – Close mowing creates a situation where the plants are unable to produce enough food to meet their own demands. • Turfgrass plants will be more susceptible to drought, high temperature, and wear injury. 45
  45. 45. Variables Influencing Mowing Height• Species/Cultivar (cont.) – Mowing above the tolerance range will reduce tillering and cause matting of the grass. • Reduced tillering results in fewer and coarser plants, while matted grass creates a good microenvironment for disease development. –Also increases thatch accumulation, which creates a need for higher maintenance. 46
  46. 46. Variables Influencing Mowing Height• Root-to-Shoot Ratio – Turfgrasses have a ratio of shoot to root tissue that is optimal to support growing grass. • If turf is mowed too low at one time, this results in an imbalanced ratio with more roots available than the plant physiologically requires. –The excess roots are then sloughed off. 47
  47. 47. Variables Influencing Mowing Height 48
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  49. 49. Variables Influencing Mowing Height• Use – The use of the site will dictate how short or tall to mow. • Putting green = 5/32" or lower. 50
  50. 50. Mowing Heights Species/Variety Use Mowing Height (in)Tifgreen Golf Greens 5/32 to 3/8Tifdwarf Golf Greens 1/8 to ¼Ultradwarfs Golf Greens 1/3 to 1/10 Champion FloraDwarf TifEagleTifway (419) Golf Tees 3/8 to 1¼Tifway II FairwaysGN1TifSportCommon Bermudagrass Fairways 1 to 4 RoughsBahiagrass Roughs 3 to 4St. Augustinegrass Out-of-Play areas 51
  51. 51. Mowing Frequency Determine the mowing frequency by the grass growth rate, not by any set schedule. Remove no more than one-third of the total leaf area at any one mowing.  For example, if you mow a St. Augustinegrass lawn at 3”, the grass should be 4” tall.  Removing more than one-third shocks the turf, which may result in temporary thinning.  Reserve carbohydrates are utilized for shoot regrowth, which will deplete the stored carbohydrates and reduce the capability of the turf to withstand environmental stresses. 52
  52. 52. Variables Influencing Mowing Height• Season (Time of year) – Spring - turfgrasses tend to have a more prostrate growth habit. • They can be mowed closer than during other seasons without consequence. • Close mowing in the spring: –controls thatch; –increases turf density; –removes excess residues or dead leaf tissue; 53 –promotes earlier green-up.
  53. 53. Variables Influencing Mowing Height• Season (Time of year) – Summer - turfgrasses tend to have a more upright growth habit and are healthier if the mowing height is raised to compensate for it. • Increases turf rooting, reducing watering needs and stresses imposed by increased nematode activity. 54
  54. 54. Variables Influencing Mowing Height• Season (Time of year) – Fall • Mowing height may need to be raised to reduce the chance of low temperature damage during winter (north Florida) and to provide cushion for grass crowns in winter where bermudagrass is dormant. 55
  55. 55. Variables Influencing Mowing Height• Shade – Under shady conditions, grass leaves grow more upright in order to capture as much of the filtered sunlight for photosynthesis as possible. • As a result, mowing height for grasses grown under these conditions needs to be raised at least 30%. –If mowing height is not raised, grasses grown under shaded conditions gradually thin out and die. 56
  56. 56. Clipping Removal• It has been taught that clippings should be removed because they contribute to thatch. – Clippings contribute very little to thatch development because clippings are primarily water and cellulose that decompose easily. – Only remove long clippings that remain on top of the grass. • Excess clippings shade the turfgrass and create a microenvironment that favors disease development. 57
  57. 57. Grass Clippings• Clippings are a source of nutrients. – Clippings provide nutrients 3-6% N, 2-3% K, 0.5-1% P. • If clippings are removed, application of additional fertilizer to compensate for those nutrients is needed. 58
  58. 58. Grass Clippings• Clippings should be removed only when they are so heavy that they smother the grass or interfere with the playing surface, such as on golf greens.• Clippings pose an environmental problem. – Most municipal landfills no longer accept them. • 14-25% of material sent to landfills is lawn debris.• Clippings from greens should be disposed of properly to prevent undesirable odors near the playing area and to prevent fire hazards. – Composted clippings can be used as a ground mulch in flower beds or inaccessible areas. 59
  59. 59. Fertilization
  60. 60. Fertilization Frequency• Ideal fertilization program would be to apply very small amounts of essential nutrients each week or two during the growing season. – Rates can be continually adjusted up or down depending on the turfgrass response. • Extremely expensive • Totally impractical 61
  61. 61. Fertilization Frequency• The presence and availability of essential plant nutrients determines the minimum fertilization frequency.• The number of fertilizations can be minimized with the use of slowly available nitrogen carriers. 62
  62. 62. Fertilization Timing• The proper timing becomes more critical as the number of applications per growing season is reduced. – Warm-season Turfgrasses • Late spring / early summer best - plants actively growing. • Late summer / early fall fertilization may reduce their cold-hardiness and result in some winterkill. 63
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  64. 64. Fertilization Timing• Cool-season Turfgrasses – Fall fertilization best - minimizes disease problems, promotes better fall color retention, and earlier spring green-up. – Early-spring / Mid-spring may encourage diseases and favors weed growth. – Early-summer / Mid-summer fertilization should be avoided to reduce stress levels. 65
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  66. 66. Fertilization Rate• General rule: Never apply more than ½ lb. of quickly available nitrogen per 1000 ft2, or 1 lb. of slowly available nitrogen per 1000 ft2. – As temperatures increase, decrease rate. – Lower mowing height, decrease single application rates • Individual shoots are smaller and thus more susceptible to injury from large concentrations of fertilizer nutrients. • Close-cut grass is often so dense that fertilizer particles cannot fall into the turf; 67
  67. 67. Methods of Application – Liquid• Foliar feeding Sprayers – Spray volumes less than 0.5 gal/1000 ft2 or lower. – Significant quantities of the nutrients are absorbed directly by the turfgrass leaves, thus the name. – Only low rates of fertilizer (1/8 lb N or Fe / 1000 ft2) should be applied to avoid burn. 68
  68. 68. Methods of Application – Liquid• Sprayers Liquid Fertilization – Spray volumes of 3 to 5 gal / 1000 ft2 are used. – With this method, much of the fertilizer is washed off the foliage, and root absorption occurs. 69
  69. 69. Granular Spreaders - Drop Spreader• Drop spreaders can provide very accurate and uniform application of granular materials.• Fertilizer exits through a series of openings at the base of the hopper.• The rate can be changed by adjusting the size of the openings. 70
  70. 70. Drop Spreader 71
  71. 71. Drop Spreader Application 72
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  73. 73. Granular Spreader - Rotary (Centrifugal) Spreaders• Very efficient for fertilizing large areas.• Fertilizer falls through one or more openings of adjustable size onto a rotating plate at the base of the hopper and is propelled away in a semicircular arc.• Most effective with uniform sized particles. 74
  74. 74. How To Properly Apply Fertilizer• Use a deflector shield when fertilizing near water bodies or impervious surfaces. 75
  75. 75. Fertilizing Around Water “Ring of Responsibility” 76
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  78. 78. Thatch Control / Cultivation• What is it? – Thatch is composed of an intermingled layer of living and dead stems, stolons, rhizomes, and roots between the green vegetation and the soil surface. 79
  79. 79. Thatch Control / Cultivation• What is the difference between thatch and mat ? – Mat is thatch intermixed with mineral matter. – Thatch may be transformed into a mat as a result of top dressings. – Like thatch, mat develops between the green vegetation and the soil surface. – Mat develops on putting greens and other areas of turf that have been top dressed. 80
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  81. 81. Thatch Control / Cultivation• What causes thatch? – Thatch is basically a residue problem that occurs in most turfgrasses. • Thatch accumulates and persists largely because the tissues occurring in the thatch contain decay resistant lignin. –Tissue components such as cellulose and hemicellulose decompose rather quickly. »Failure to remove clippings after mowing does not cause thatch 82
  82. 82. Thatch Buildup• Attributed to: – Species & Cultivars • Different species produce thatch at different rates. –Perennial ryegrass produce less than most other cool-season grasses. –St. Augustinegrass, hybrid bermudagrass and zoysiagrass may have excessive thatch accumulation, while centipedegrass and bahiagrass also form thatch, but at a slower rate. 83
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  86. 86. Thatch Buildup• Attributed to: – Improper management • Mowing –In general an increase in mowing height will cause an increase in thatch. • Excessive Fertilization –High levels of nitrogen fertilizer results in increased thatch accumulation. 87
  87. 87. Thatch Depth as Influenced by Mowing Height 88
  88. 88. Why is thatch a problem?• Only when thatch becomes excessive is it a problem. – Moderate thatch accumulation can • Cushion turf, • Improve wear tolerance, and • Moderate soil temperatures. 89
  89. 89. Why is thatch a problem?• Excessive thatch results in numerous problems. – Foot printing • Excessive thatch promotes a spongy surface that can foot print, or even worse disrupts the smooth, firm surface needed on putting greens. – Scalping • When the thatch becomes excessive, the turf gets puffy and becomes prone to scalping from mowers which causes severe injury. 90
  90. 90. Foot Printing 91
  91. 91. Scalping 92
  92. 92. Why is thatch a problem?• Localized Dry Spot – Thatch has profound effects on water relations in turf. • Under normal conditions thatch will allow rapid percolation of water through its large pores. • Upon reaching the thatch-soil interface, however, downward water movement slows resulting in a temporary water table within the thatch. 93
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  94. 94. Why is thatch a problem?• Localized Dry Spot – As evapotranspiration proceeds and moisture in the thatch zone is depleted, water from the underlying soil (finer textured medium) does not move readily into the dry thatch (coarser textured medium). • As a result a thatchy turf will often wilt even though the soil beneath has adequate water. 95
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  96. 96. Why is thatch a problem?• Localized Dry Spot – Thatch becomes hydrophobic once it dries out. • When this occurs uniform wetting from irrigation is impossible because water fails to penetrate the surface. • One solution to localized dry spots is the addition of wetting agents which reduce the surface tension and allow water to penetrate thatch. 97
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  99. 99. No Wetting Agent Wetting Agent 100
  100. 100. Why is thatch a problem?• Wet Spots – On heavily thatched athletic fields subject to traffic and wear during the wet season, thatch may become compressed and stay saturated. • When this occurs, the thatch often acts as a sponge and impedes water movement into even a porous rooting medium. 101
  101. 101. Why is thatch a problem? Reduced Drought, Heat, and Cold Tolerance  Extreme differences in bulk density between thatch and the underlying soil reduce drought tolerance since root growth occurs primarily in the thatch zone and not in the compacted soil.  Without excessive thatch, root and rhizome growth occurs in the soil and roots can draw moisture from a larger, more stable reservoir.  Turfgrass crowns, stolons, and rhizomes tend to be elevated and grow in the thatch instead of the soil.  This brings them into closer proximity to the temperature extremes. 102
  102. 102. Why is thatch a problem?• Poor Fertilizer Response – Thatch is a poor environment for microorganisms to live. • Upon fertilizer application, the particles become trapped in the thatch layer. –Fertilizer activity that is dependent of microbial breakdown will be limited.• Poor Color Retention – Thatch free turf retains color longer. 103
  103. 103. Poor Fertilizer Response 104
  104. 104. Why is thatch a problem?• Increased Pest Problems – Thatch layers provide environments for some disease and insect organisms to live. • Brown patch, dollar spot, and leaf spot diseases as well as sod webworms are examples.• Reduced Effectiveness of Overseeding – Overseeding turfs with high thatch levels very difficult because seed is planted into the thatch, and not the soil. 105
  105. 105. Thatch Control – Mechanical Removal Vertical mowers for dethatching generally utilize either solid blades, flail blades, or spring tines. A vertical mower has a series of knives vertically mounted on a horizontal shaft.  The shaft is rotated at high speeds and the blades slice into the turf and rip out thatch and other debris. Dethatching machines are available in a variety of sizes. The objective is to remove as much thatch as possible without damaging the turf. 106
  106. 106. Thatch Control – Mechanical Removal• Vertical mowing is quite disruptive – Timing is important - it should be timed to precede a period of major vegetative growth. • Cool-season grasses = early spring • Warm-season grasses = early summer – Improper timing can result in weed invasion because the turf is open. 107
  107. 107. Power Raking 108
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  109. 109. Power Raking 110
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  111. 111. Power Raking Promotes Early Green-up 112
  112. 112. Vertical Mowing (Verticutting)• Vertical mowing meets different objectives depending on the depth of the knives: – Slight - grain is reduced when knives are set to just nick the surface of the turf. – Shallow - breaks up cores following aerification, facilitating a topdressing effect. – Deep - stimulates new growth when stolons and rhizomes are severed and results in removal of accumulated thatch. 113
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  114. 114. Post Verticutting Care Soil and thatch should be dry or turfgrass injury will be more extensive, since moist conditions encourage excessive plant material to be removed. Following verticutting, debris should be removed and the area immediately irrigated. Apply 0.5 pound of quick-release nitrogen per 1,000 ft2 to encourage rapid recovery. A 30-day period of favorable growth is needed for the turf to recover.  Therefore, the last vertical mowing of the season should be timed at least four weeks before the average frost. 115
  115. 115. Grooming• A groomer is a miniature vertical mower mounted in front of the reel cutting unit of a greensmower. – Each time the turf is mowed with this unit, the turf is lightly vertically mowed (or groomed). • Improves the surface by standing up the leaf blades before mowing – removing surface grain. 116
  116. 116. GroomingGroomers are easily knockedout of adjustment and muchcaution should be used. 117
  117. 117. Thatch Control• Biological Control – This approach utilizes management techniques that create an environment that is conducive to thatch decomposition. • Topdressing • Core Aerification • Spiking/Slicing • Grooming 118
  118. 118. Topdressing• Adds a thin layer of soil or root zone mix to the turf surface which is then incorporated by dragging or brushing it in. – On newly established turf, topdressing: • partially covers and stabilizes the newly planted material; • smooths gaps that result from sodding; and • minimizes turfgrass desiccation. 119
  119. 119. Topdressing• On established turf, topdressing: – smooths the playing surface; – controls thatch and grain; – promotes recovery from injury; and – can change the physical characteristics of the underlying soil. 120
  120. 120. Belt-Type Topdresser 121
  121. 121. Topdressing Frequency & Amounts:  Following coring and heavy verticutting, moderate to heavy topdressing amounts are used to help smooth the surface, fill coring holes, and cover exposed roots.  Irregular playing surfaces or soil profile renovation will require frequent and relative heavy topdressing.  Rates range from 1/8” to 1/4” (2 to 4 yds3 of soil per 5,000 ft2.)  Soil Physical Characteristic changes -  Heavy topdressing program following numerous deep core removal operations over a period of years is required. 122
  122. 122. Improper Topdressing Layers Developed 123
  123. 123. Topdressing• Materials: – Topdressing material should match the construction material. • The only difference may be the absence of organic matter. –Enough organic matter is produced over time by turfgrass plants to cover future needs. 124
  124. 124. Topdressing• Materials – Pure Sand: • Sandy soils tend to produce harder (firm) playing surfaces that do not hold approaching shots well. • Sandy soils also require an increase in nutrient and water application since they drain so well and localized dry spots may develop if the sand becomes hydrophobic. 125
  125. 125. Topdressing Home Lawns 126
  126. 126. Topdressing Home Lawns 127
  127. 127. Aerification or Coring• Is the removal of small soil cores or plugs from the turf surface. – Normally 1/4” to 3/4” in diameter, however, larger sizes are now available. – 2” to 4” depths with cores spaced on 2” to 6” centers. 128
  128. 128. Aerification or Coring – Benefits Relieves soil compaction Allows deeper, faster penetration of water, air, fertilizer, lime, and pesticides. Allows for release of toxic gases (CO2 and CO) from the root zone. Improves surface drainage. Penetrates through soil layers that develop form topdressing with dissimilar materials. Thatch control by stimulating microbe environment. Increased rooting. 130
  129. 129. Aerification or Coring - Disadvantages• Temporary surface disruption.• Increased turf surface desiccation as roots are exposed.• Coring holes provide a habitat for insects (cutworms). 131
  130. 130. Slicing• A slicer has a thin, V-shaped knives bolted at intervals to the perimeter of metal wheels that cut into the soil. – Turf is sliced with narrow slits about 1/4”-wide 2” to 4” deep. – Much faster than coring and does not interfere with turf use since there is no removal of cores. – Performed on fairways and athletic fields and other large, trafficked areas during mid- summer stress periods when coring may be 132 too injurious or disruptive.
  131. 131. Spiking• A spiker provides an effect similar to a slicer. – The penetration is limited to approximately 1”, however, the distance between perforations along the turf’s surface is shorter. • Spiking causes less disruption than coring. – Used for: • breaking up soil surface crusting; • breaking up algae layers; and • improving water penetration and aeration. 133
  132. 132. Thatch Control• Integrated Cultural Practices – Fertilization • Avoid excessive application of fertilizer. – Maintain pH of soil • A pH of 7.0 is ideal for maximum microbial activity and decomposition. – Proper Watering • Maximum decomposition occurs if the soil is at optimum moisture, not too wet or too dry. 134 – Mowing Practices