What is the definition of thatch in turf management?

The definition of thatch in turf management is a layer of living and decomposing turfgrass roots and leaves. Thatch is an organic matter that accumulates on the surface of the soil beneath the turfgrass canopy. It consists primarily of stems, roots, and other plant debris that haven't fully decomposed. This layer can be beneficial to the turf when it is thin, as it helps retain moisture and provides a cushion for foot traffic. However, when thatch builds up excessively, it can inhibit water and nutrient absorption, leading to issues with turf health.

In contrast, the other options do not accurately describe thatch. A dense layer of soil refers to the physical soil structure rather than organic material. A type of pesticide implies a chemical control product, which does not relate to the biological composition of turf. Non-organic matter suggests material that is synthetic or mineral-based, further diverging from the organic nature of thatch.