Effectiveness of Cultural Thatch‐Mat Controls for Young and Mature Kikuyu Turfgrass

Abstract

Excessive thatch and mat can be detrimental to turfgrass health and management. Mechanical and topdressing techniques to reduce accumulation of thatch and mat were evaluated in a 24-mo fi eld study of kikuyu [Pennisetum clandestinum (Hochst. ex Chiov.)] turfgrass of two contrasting organic matter (OM) contents in the surface 50 mm of soil. Treatments included two kikuyugrass ages (established from 20 wk or 20-yr-old kikuyugrass) and fi ve renovation techniques (none, verticutting, coring, topdressing with sand, coring + topdressing). Th e renovation techniques varied in eff ectiveness depending on the initial OM content of the soil immediately underlying the kikuyugrass. Annual verticutting, or twice annual topdressing with or without annual coring a young kikuyugrass were most successful at restricting the accumulation of soil OM (P < 0.05), with OM content <3.5% by 24 mo. Twice annual topdressing with or without annual coring, most rapidly decreased soil OM in the mature kikuyugrass (P < 0.05), with OM content averaging 6.2% by 24 mo. Combining coring with topdressing did not necessarily further decrease OM contents. Topdressing was up to three times more eff ective at reducing soil OM content than coring alone (P < 0.05). Th e color and N concentration of both kikuyugrass ages was maintained to local standards by all mechanical and topdressing techniques, although verticutting decreased the incidence of mower scalping in the second year. Verticutting was the most eff ective approach for restricting the progressive soft ening of young kikuyugrass with time (P < 0.05), whereas the mature kikuyugrass soft ened by the same amount irrespective of the renovation treatment.

Granular wetting agents ameliorate water repellency in turfgrass of contrasting soil organic matter content

“…Various methods are used for decreasing the OM content in soil underlying turfgrass. At the present study site, renovation techniques varied in their effectiveness to decrease soil OM depending on the initial OM content of the soil immediately underlying the kikuyugrass (Barton et al 2009b). For example, annual verticutting or twice annual topdressing the younger kikuyugrass were most successful at restricting the accumulation of soil OM, while twice annual topdressing most rapidly decreased soil OM in the older kikuyugrass (Barton et al 2009b).…”

“…At the present study site, renovation techniques varied in their effectiveness to decrease soil OM depending on the initial OM content of the soil immediately underlying the kikuyugrass (Barton et al 2009b). For example, annual verticutting or twice annual topdressing the younger kikuyugrass were most successful at restricting the accumulation of soil OM, while twice annual topdressing most rapidly decreased soil OM in the older kikuyugrass (Barton et al 2009b). Applying the same amount of an effective soil wetting agent decreased soil water repellency to a greater extent in the younger turfgrass than the older turfgrass in the present study; particularly in the first 4 weeks following application.…”

“…The older turfgrass was cut from a golf course fairway to a depth of 50 mm so as to include a mat layer of high OM content, while the younger turfgrass was newly-grown sod with a depth of 15 mm. The soil OM content of the surface 50 mm of the older turfgrass was 32±1% OM, and for the younger turfgrass was 8.6±1% OM; measured on the 20 November 2008 using combustion at 600°C (Barton et al 2009b;Carrow et al 1987). The soil wetting agent treatments were either products 3, 4, 9, 10 or nil (control), and applied at the manufacturer's recommended rate and frequency (Table 1).…”

“…These assessments of liquid wetting agents involved intensively managed turfgrass systems (i.e., sports grounds and golf courses), but in less resource-intensive turfgrass systems in Australia, granular wetting agent formulations are often used. Furthermore, the turfgrass may also contain high organic matter (OM) content due to irregular renovation (Barton et al 2009b). Given the number of factors influencing the effectiveness of soil wetting agents, choosing a soil wetting agent is not considered a simple process by turfgrass managers (Karnok 2006).…”

Characterization, Development, and Management of Organic Matter in Turfgrass Systems

“…Barton et al (2009) described mat as a "tightly intermingled layer of decomposing OM and soil, usually brown in color and easily distinguishable at the upper surface of the root zone." Because of inherent ambiguity in terminology and sampling techniques, the term thatch-mat has appeared frequently since the late 2000s (McCarty et al, 2007;Barton et al, 2009;Fu et al, 2009). Close observation reveals that the thatch-mat layer, if it exists, is the uppermost portion of the growing medium for turf.…”