Wednesday, November 7, 2007 - 9:15 AM

Effect of Mulched Maple Leaves on Common Dandelion in Established Kentucky Bluegrass.

Alexander Kowalewski, Douglas Buhler, Suzanne Lang, Muraleedharan Nair, and John Rogers. Michigan State University, Michigan State University, 162 PSSB, East Lansing, MI 48824

Research conducted at Michigan State University (1998) showed that maple (Acer spp.) leaf litter mulched into established turfgrass as a disposal method resulted in fewer weeds than control plots and plots treated with oak (Quercus spp.) leaf mulch. However, findings could have been the result of herbicide residues on the mulched leaves. Also, leaves were separated by genus, not species. This presents the opportunity for new research comparing the effects of different mulched maple species, collected from known herbicide free tree plantations, on broadleaf weeds in a cool-season turfgrass zone. The objectives of this study were to a) quantify the effectiveness of maple leaf mulch as an organic broadleaf weed control method, and b) identify which maple species and at what rate (particle size and rate per unit area) provide the most effective control. The experimental design was a RCBD in a 5x2x2+1 factorial, tree leaf species, leaf particle size, leaf application rate, and control, respectively. Leaf species were red maple (Acer rubrum L.), silver maple (A. saccharinum L.), sugar maple (A. saccharum M.), sugar maple (high sugar content), and red oak (Quercus rubrum L.). Particle sizes were coarse (2.5-6.4 cm2) and fine (1.3 cm2), and application rates were low (0.5 kg m-2) and high (1.5 kg m-2). Data were collected in 2004 and 2005 on Kentucky bluegrass (Poa pratensis L.) spring green-up, and clipping yield, surface temperature, soil temperature, soil moisture content, and common dandelion (Taraxacum officinale W.) plant counts. Results obtained in 2004 and 2005 showed that after one annual application of fall tree leaves, the high mulch application rate provided the greatest dandelion control, up to 80% (2004) and 70% (2005) in comparison to the control regardless of tree leaf species. Results also indicate that sugar maple species provide the greatest dandelion control, up to 81% (2004).