TURF TIPS
Rx
for Heavily Trafficked Turf Tom Samples,a John Sorochana and Alan Windhamb The University of Tennessee
T
urfs often receive extra-heavy traffic during special events. Turfgrasses may be injured and soils may compact as visitors or vehicles move throughout the landscape. Tents, outdoor displays and portable flooring may shade the turf and limit air flow among plants. Water may pool and soils may erode if rain falls. Several turf care practices implemented before, during and after an event, in addition to routine mowing, fertilization and irrigation, may help protect or strengthen turfgrasses and speed their recovery.
Cultivation depth, spacing and levels of soil loosening and soil disruption of several aeration methods.
Before:
Aeration Method
Cultivation Depth (inches) Soil Loosening
Turf Disruption
Hollow Tine
2 to12
low to high
medium to heavy
Slice
2 to 8
low
low
Solid Tine
2 to 16
low
low to medium
1. Aeration. Turfs can be “selectively” cultivated to relieve compaction and speed the movement of air, water and nutrients into the soil. Soil aeration may be accomplished using several machines including slicers, spikers and hollow-tine (core), deep-tine (hollow or solid), deep-drill and water-injection aerators. The benefits of slicing and spiking are considered short term in duration compared to core aeration. However, slicing and spiking can temporarily “part” the thatch, and speed the movement of water from the turf surface into the soil. Although benefits of core aeration are long-lived compared to slicing or spiking, this cultivation method does injure turfgrasses and disrupt the turf surface. Turfgrasses may require several weeks to fully recover and conceal aeration channels following core aeration.
Spike
1/4 to 2
low
low
Water Injection
4 to 20
low to medium
low
Liming Material
Chemical Formula
Rate of Release
Potential to Burn Turf
2. Nitrogen and potassium. Prevent excessively lush growth before and during an event by reducing the amount of nitrogen available for plant uptake from the soil. Rapidly growing turfgrasses containing high levels of nitrogen in leaf and stem tissues are often prone to wear injury and disease. Rather than applying a fertilizer containing concentrated, water-soluble nitrogen days before an event, consider an application of potassium (e.g. one pound of potassium per 1,000 sq. ft.). Potassium applied several weeks before an event may help strengthen turfgrasses while improving drought and high temperature tolerance as well as disease resistance.
Calcium Carbonate
CaCO3
slow
low
Calcium Oxide
CaO
fast
high
slow
low
3. Liming. Apply lime according to soil test recommendations. The availability of mineral nutrients in soils can be maximized by maintaining a pH from 6.0 to 6.5. Routine nitrogen fertilization often increases the acidity of the soil and lowers the soil pH. Applying lime several weeks before an event will neutralize soil acids, increase pH and provide calcium. Turfgrass leaves contain large (e.g. 1/5 to 1 16
Level of
TENNESSEE TURFGRASS AUGUST/SEPTEMBER 2003
a
Department of Plant Sciences and Landscape Systems, The University of Tennessee
b
Department of Entomology and Plant Pathology, The University of Tennessee
Chemical formula, release rate and foliar burn potential of several liming materials.
Dolomitic Limestone CaCO3*MgCO3 Hydrated Lime
Ca(OH2)*Mg(OH2) medium
high
Quicklime
CaO*MgO
high
fast
percent of the dry weight) quantities of this essential nutrient. Calcium is permanently fixed in the walls of plant cells. Sloweracting liming materials such as calcium carbonate and dolomitic limestone are preferred for application to established turf due to a relatively low foliar-burn potential. Dolomitic limestone is an excellent source of both magnesium and calcium. Gypsum (calcium sulfate) can be applied to turfs to supply calcium and sulfur with little, if any effect on the soil pH. Gypsum contains approximately 20 percent calcium and 19 percent sulfur.
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