THATCH

PART 2

ADVANTAGES AND DISADVANTAGES OF THATCH IN SPORTS TURF

Numerous research projects have found that thatch can become a problem when it’s thickness exceeds 12mm. But for most sports, a thin, uniform thatch layer can improve turf quality.

Advantages of thatch maintained at a 12mm or less:

• Increased resiliency.
• Increased wear tolerance.
• Increased impact absorption.
• Insulates soil against extreme temperature changes.

This benefits of thatch are especially important in contact sports were players frequently impact the field surface. 

Disadvantages of thatch unmanaged over a 12mm.

• Provides a desirable environment for turf insects. Insect injury is more severe on grasses with growth restricted to thatch.
• Provides conditions favorable for disease organisms. Disease injury is more severe on grasses with growth restricted to thatch.
• Promotes shallow rooting by limiting root and rhizome penetration into the soil.
• Can create hydrophobic turf.
• Can affect performance of ball roll and bounce.
• Can prevent seed establishment

MAINTAINING A MANAGED THATCH LAYER

There are many factors affecting the thatch status of a turf ecosystem. However, since there are clear benefit to having a managed thatch layer on most types of sports field, careful management can be well worth the effort.

Creating a suitable managed thatch layer is also assisted by appropriated cultural practices. Top dressing with sand helps to firm the thatch layer and integrate the thatch with the turf and the soil. The resulting thatch sand mat is more beneficial than a loose thatch layer that causes shallow rooting and hydrophobic conditions. Core aeration promotes thatch decomposition, but like top dressing, this practice helps to firm the remaining thatch layer, providing a better surface for player performance. 

REDUCE EXCESSIVE THATCH BUILDUP

Mechanical Thatch control

One of the most common methods of thatch control is vertical mowing (dethatching).  As the name indicated, the blades of the mower cut vertically into the turf canopy, severing lateral stems and removing some of the thatch that develop on the surface of the soil.

Thatch should only be removed before or during periods of active turfgrass growth. This will ensure recovery from injury that may result during removal.