LAWN & TURF: SPRINT/SUMMER - COMPACTION

Effects from vehicular or foot traffic can cause injury to turfgrass in two ways:

Injury is grass shoot tissue manifested by abrasion, tearing, or stripping of the leaf tissue.

Damage from traffic to the root system resulting from soil compaction due to traffic weight. Often damage from traffic will cause both types of injury simultaneously.
Rates of recovery of the grass vary based on, the capacity of the grass to tolerate traffic injury, the growth rate of the turf and how long it will take to grow out, and the degree of severity.

There are specific management and maintenance practices that will improve the wear tolerance of your turfgrass. Warm-season grasses grown throughout Florida are generally more wear tolerant than cool-season grasses grown in northern climates.

The factors, other than genetics, that are important in determining wear tolerance are:
• Amount of shoot tissue present to absorb the injury.
• Proper hydration status.
• Proper fertilization practices.
• Potassium.
• Avoiding injury, if possible.

For constant vehicular or foot traffic use pavement, brick or stone ground cover.

Fertilization regimes strongly influence the ability of the grass to withstand injury. Excess nitrogen reduces wear tolerance. Proper nitrogen fertilization improves wear tolerance.

Proper potassium fertilization allows grass to survive with less injury and retains adequate carbohydrates for regrowth. Potassium should be in an amount ranging from ½ to equal amounts of potassium to nitrogen. (16-4-8 would supply ½ the amount of potassium to nitrogen).

Mowing practices influence your grass wear tolerance. Higher mowing heights improve tolerance. Scalping, or low mowing, results in greater damage, slower recovery, and possible death. Adequate irrigation allows turf to absorb, resulting in less damage than on dry turf.

If soil compaction is the primary problem, there are several steps to be taken:

• Compaction can be alleviated by aeration of the soil, allowing oxygen to reach roots.
• Aerate using a small foot-press aerator in small areas.
• For larger jobs use equipment to drill holes in the soil.
• Follow by top-dressing, which may alleviate compaction, reduce thatch, and improve the drainage or water retention of the site.
• Remember that some traffic may be unavoidable on your lawn. In these cases, adopting a "wear-tolerant" attitude may be helpful.

 
For more information go to: http://edis.ifas.ufl.edu/EP071
Minimizing Traffic Damage to Your Florida Lawn. L.E. Trenholm.Department of Environmental Horticulture, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published: August 2000.

AERATION

Core-type aeration is recommended to relieve soil compaction. Compacted soil does not have the proper amount of oxygen for deep rooting of the grass, and will result in the grass thinning, or showing excess wear and tear from what would otherwise be normal use. Additionally, in dry periods, compacted soil does not absorb water properly and will often actually repel irrigation water.

Soil compaction can result from a number of causes. Pedestrian or equipment traffic, heavy organic soil in poorly drained areas, trees depleting the organic matter in the soil causing it to collapse, and fill soil with heavy clay content can all result in compacted soil.

Core type aeration machines can be rented at many equipment rental stores. When aerating a lawn, be sure to use a machine that will remove a core of soil and NOT simply punch holes in the ground. Spikes punched into the soil do not relieve compaction; in fact they increase compaction. The soil should be wet before aerating, so the soil core will be removed intact, and the yard should be covered twice, once north and south, and a second time, east and west. Leave the removed cores where they fall. They will disappear after a few days.

Aeration can also be beneficial in helping to accelerate thatch decomposition by increasing the air circulation to the thatch layer