Slide 1 LHAP 106 Turfgrass Maintenance Regular Care: Water Slide 2 What is the Function of Turfgrass Maintenance? ie: if grasses are our native plant material here, why do we have to maintain it so much? Native grasses link Slide 3 How Do Plants Use Water? Slide 4 Water Use: Photosynthesis & Turgidity Required for photosynthesis Transport medium for starches, sugars, & carbs With sufficient turgidity, Stomata open Cells are stronger Wilted plants lose aggressiveness, wear tolerance and recuperative ability Slide 5 Water Use: Transpiration Absorption, transport and release of water via xylem Regulates leaf temperature Pulls fertilizer in solution throughout the plant Process is at its peak on hot, dry days and slower at night or cooler, moist conditions Different types of grasses have different water content and requirements. ANY damage will require more moisture. Slide 6 Water Gain: Absorption Most water absorption occurs through the root hairs Secondary absorption through the foliage – leaves and stems Slide 7 Water Gain: Absorption Rate of absorption depends on: Number of root tips Rate of root growth How deep the root system has grown Amount of available water in rootzone Soil temperature Rate of absorption is reduced by: Excessive Nitrogen or Sodium Over watering Compacted soils Slide 8 Water Loss Sources: EVAPOTRANSPIRATION Leaf Surfaces Evaporation from soil with low density Wind Wicks away moisture Cool strong winds are worse than light hot breezes. Slide 9 Water Loss The initial symptom of water deficits is a colour change from emerald green to dark blue green Wilt occurs after colour change Turfgrass lays down or leaves droop and stay that way “footprinting” No permanent damage from wilt Wilt greatly reduces a plant’s ability to withstand wear Slide 10 Slide 11 Wilt Traffic over wilted turfgrasses can result in injury Cell walls can be permanently damaged In extreme cases, the plant can’t recover when water is replaced Leaf tips will be dead above where the damage has occurred Plant will regrow when watered again (dead growth can be mowed off) Signs of initial wilt present as “foot printing” - the inability of the grass to spring back after being walked on. Slide 12 Wilt - Remediation Reduce transpiration Proper irrigation Syringe after first symptoms appear Increase absorption Maintain active healthy roots Slide 13 Drought: Summer Dormancy Prolonged water stress that limits or prevents turfgrass growth Wilting cycle is repeated Leaf firing and dormancy Death of plant if water deficit continues for a sufficient period of time Extended periods with no irrigation, high ET rate, no precipitation Slide 14 Slide 15 KB summer dormancy Slide 16 Kentucky Bluegrass Lawn in Picture Butte, Alberta. (July) One week of watering once a day with the sprinkler broke summer dormancy of cool season grass. Slide 17 Water Sources Slide 18 Precipitation Effectiveness of precipitation depends on degree of water infiltration into the soil. All irrigation systems should have their precip rates (PR) closely aligned with the infiltration rate of the soil high intensity cycles that exceed infiltration rates promote excessive water loss through runoff frequent light irrigation promotes shallow rooted species (Poa annua) and water is lost to evaporation Slide 19 Precipitation Rule of Thumb: Long duration/low intensity irrigation cycles promote deep rooted turfgrass species and places stress on shallow rooted species Water Out must balance Water In (internally). The timing and rate of irrigation must be adjusted in relation to natural precipitation received