Discussion Classes

1. Discussion Classes Blue Course Green

2. Analysis

3. general deterioration of #4 green

4. shade from trees and tower general deterioration of #4 green

5. shade from trees and tower poor air circulation from trees and shrubs general deterioration of #4 green

6. shade from trees and tower poor air circulation from trees and shrubs general deterioration of #4 green concentrated traffic between trap and green

7. shade from trees and tower poor air circulation from trees and shrubs general deterioration of #4 green concentrated traffic between trap and green poor internal and surface drainage

8. shade from trees and tower poor air circulation from trees and shrubs general deterioration of #4 green concentrated traffic between trap and green poor internal and surface drainage

9. shade from trees and tower poor air circulation from trees and shrubs delicate turfgrass hot, humid microenvironment general deterioration of #4 green O2-deficient rootzone concentrated traffic between trap and green poor internal and surface drainage

10. QUANTITATIVE reduced photosynthetically active radiation (PAR) QUALITATIVE photomorphogenetic response due to phytochrome Shade Effects

11. Effect of Reduced PAR on Net Photosynthesis Light compensation point: • PAR intensity at which photosynthesis = respiration • No net exchange of CO2 & O2 • Higher in C3 species Light saturation point: • PAR intensity at which additional light yields no increase in photosynthesis • Higher in C4 species

12. Red and Blue Light Photosynthetically active wavelengths include: • red light at 600-700 nm. • blue light at 400-500 nm. Other wavelengths are: • green light at 500-580 nm, which is reflected. • far-red light at 700-770 nm, which is transmitted.

13. Far Red Light • PAR (red & blue light) intensity are reduced by shading. • Light transmitted through tree canopies comes through at longer wavelengths, including far red light.

14. Phytochrome Pr Pfr Pr - blue pigment that absorbs red light, converting phytochrome from the inactive form (Pr) to the active form (Pfr). Pfr - olive-green pigment that absorbs far-red light, converting phytochrome from the active form (Pfr) to the inactive form (Pr); this conversion also occurs slowly in the dark.

15. Active (Pfr) Inhibits stem and leaf elongation Promotes tillering Inactive (Pr) Promotes stem and leaf elongation Inhibits tillering Phytochrome

16. Other Shade Effects • Thinner leaves and cuticles • Shallower rooting • Reduced carbohydrate reserves A “shade” turf is thus more delicate and less tolerant of wear, disease, and environmental stresses.

17. shade from trees and tower reduced PAR and inactive phytochrome delicate turfgrass reduced tolerance to environmental stresses general deterioration of #4 green

18. Poor Air Circulation • Closely planted trees and shrubs restrict air flow, resulting in a warmer, more humid microenvironment. • As a consequence, disease pressure is greater.

19. Wind Effect Wind moves parcels of air from the turf and incorporates them into the larger volume of air above it. Thus, the accumulation of heat and humidity are dissipated.

20. Moisture Moisture accumulation within a turfgrass canopy comes primarily from an evaporative process, called transpiration.

21. Transpiration Water is absorbed by roots, translocates upward, and accumulates as films of moisture on internal leaf cells. Water films evaporate and exist the leaf through pores, called stomates.

22. Boundary Layer Water vapor exiting the stomates accumulates in a layer of humid air immediately around the leaf. With the development of boundary layers around all leaves, the environment of the turfgrass canopy can become quite humid.

23. Wind Effect With moderate air movement across the turf, however, the humidity of this environment can be substantially reduced. And the potential for disease is proportionately reduced.

24. shade from trees and tower poor air circulation from trees and shrubs reduced PAR and inactive phytochrome allows build-up of temperature and humidity delicate turfgrass hot, humid microenvironment reduced tolerance to environmental stresses increased disease potential general deterioration of #4 green

25. Surface Drainage Reflects the ease with which water can move downslope. Reflects access to catch basins through which surface water can be removed from a site. Internal Drainage Reflects the ease with which water can move through the soil matrix. Reflects the presence or absence of obstacles (e.g., pans, layers) to internal soil water movement. Poor Drainage

26. Surface Drainage To the extent that water falls at a rate in excess of a turf’s infiltration capacity, the excess will flow downslope and accumulate in depressions. Catch basins situated in depressions can remove surface water and conduct it to drain lines or elsewhere.

27. Internal Drainage Water moves through the pores permeating the soil matrix. The larger the pores, the faster the movement of water through the soil.

28. Soil Water Water movement from a saturated soil is from the macropores and is due to gravity; thus it is called gravitational water. Water in the mesopores and micropores is called available and unavailable water, respectively.

29. Soil Aeration As water drains from the macropores, O2 is drawn in and CO2 and other gases are liberated from the soil. A favorable relationship between O2 and CO2 in the turf rootzone is thus maintained.

30. Soil Water Movement Therefore, the rate at which water moves through the soil reflects its porosity and pore-size distribution. Soils with a high proportion of macropores (i.e., coarse textured soils) conduct water more rapidly than finer textured soils. As the surface dries from ET, water moves up from lower regions of the soil.

31. Water Potential (Yw) YW is a measure of the energy status of water; as free standing water has no energy, its YW = 0. Soil water potential is symbolized by YSW The components of water potential are: matric potential (YM), osmotic potential (YO), and pressure potential (YP). YSW is measured in units of pressure, including bars and Pascals; 1 bar = 100 kP or 1 cb = 1 kP.

32. Matric Potential (YM) This reflects the amount of water retained by the soil matrix. As this amount declines, the water films surrounding soil particles become thinner and are held more tightly, and YW decreases correspondingly. • At saturation, YM is near 0. • At field capacity, YM = -0.1 to -0.33 bar (-10 to -33 kPa). • At the permanent wilting point, YM = -15 bar (-1500 kPa).

33. Osmotic Potential (YO) This reflects the concentration of solutes in the soil water. As this concentration increases, YO decreases. In pure water (containing no solutes), YO = 0. In saline soils, the combination of YO and YM can reduce YSW dramatically, especially as the soil dries (e.g., where YO = -216 kP and YM = -200 kP, YSW = -416 kP, which indicates a major reduction in soil water availability).

34. Pressure Potential (YP) This reflects the positive pressure to which water may be subjected in some environments. In a glass of water, the water at the top of the glass would have a YP of 0; however, the YP of the water at the bottom would have a positive number. Where a perched water table exists above the base of a soil or sand layer, the YO may be positive as well; however, YO = 0 in most soils.

35. Textural Layers Textural layers within the soil profile can seriously disrupt water movement. Where a fine textured layer occurs above a coarse textured layer, a perched water table can form. Conversely, where a coarse textured layer occurs above a fine textured layer, a temporary water table can form.

36. Soil Structure As a soil becomes more compacted: • bulk density increases • porosity (especially macroporosity) decreases • water movement through the soil is restricted

37. Water Potential Gradient Water moves from a region of higher YW to a region of lower YW in the soil. This difference in YW is called the water potential gradient. As plant roots absorb water, the YW around the roots decreases, creating a water potential gradient.

38. shade from trees and tower poor air circulation from trees and shrubs reduced PAR and inactive phytochrome allows build-up of temperature and humidity delicate turfgrass hot, humid microenvironment reduced tolerance to environmental stresses increased disease potential general deterioration of #4 green poor soil aeration O2-deficient rootzone poor growth, increased compaction poor internal and surface drainage

39. Traffic Depending on the nature, intensity, and duration of traffic, affected turfs are susceptible to increased: • turfgrass wear • soil compaction • rutting and soil displacement • divots and ball marks

40. Traffic Threshold The traffic threshold (TT) is the traffic intensity above which a measurable deterioration in turf quality is likely to occur. Factors that can decrease TT include unfavorable cultural practices and environmental conditions, and poorly adapted turfgrasses.

41. shade from trees and tower poor air circulation from trees and shrubs reduced PAR and inactive phytochrome allows build-up of temperature and humidity delicate turfgrass hot, humid microenvironment reduced tolerance to environmental stresses increased disease potential general deterioration of #4 green induces severe wear and compaction poor soil aeration O2-deficient rootzone poor growth, increased compaction concentrated traffic between trap and green poor internal and surface drainage

42. Solutions

43. Advantages Solution #1 Disadvantages Advantages Problem Statement Solution #2 Decision Disadvantages Advantages Solution #3 Disadvantages

44. Tree Pruning/Removal Inexpensive alternative Enables addressing air circulation problem Ownership concern Green Relocation Expensive alternative Enables addressing other problems (air circulation, drainage, traffic) Shade Strategies

45. Tree Pruning/Removal Inexpensive alternative Enables addressing shade problem Ownership concern Green Relocation Expensive alternative Enables addressing other problems (shade, drainage, traffic) Fan Installation Works where other (tree removal, green relocation) strategies are not practical Cost of running power to fan locations Noise Installation Reliability Air Circulation Strategies

46. Green Reconstruction Expensive alternative Enables addressing other problems (shade, air circulation, internal drainage, traffic) Improve Sloping Inexpensive alternative Reduces internal drainage problem by lessening hydraulic loading Surface Drainage Strategies

47. Green Reconstruction Expensive alternative Enables addressing other problems (shade, air circulation, surface drainage, traffic) Cultivation/Topdressing Inexpensive alternative Increases volume of suitable rootzone Drill & Fill Provides water access to more-permeable soil Internal Drainage Strategies

48. Reduce Traffic Intensity Increase green size Increase access to/from green Move sand bunkers further away from green Increase TT Reduce shade Improve air circulation and drainage Replace annual bluegrass with creeping bentgrass Traffic Strategies