ABSTRACT
It is a common turf maintenance practice in temperate climate zones to collect and remove fallen deciduous tree leaves from turfgrass sites in the late fall into the spring. Without tree leaf removal, turfgrasses can sustain sever damage due to light exclusion and high temperature buildup. The collection and tree leaf removal processes are very labor intensive, costly and sites for disposal are becoming very limited. With the development and wide spread use of mulching mowers, it is now possible to mow fallen tree leaves, thus, depositing them into the turfgrass canopy. The hypothesis tested in this study was that yearly tree leaf deposition would have no effect on Kentucky bluegrass (Poa pratenses L.) shoot growth, visual quality, soil pH and thatch accumulation and, thus, would be a suitable landscape/solid waste disposal method. Fallen leaves of red oak (Quercus ruba L.) and Norway maple (Acer platanoides L.) were air-dried, deposited on the turf surface at a rate of 0.54 kg of dry leaves/m2 (about 12 cm thick layer) and mown with a mulching mower. Turfgrass clipping yields were collected weekly and at least monthly visual quality ratings were determined. Thatch thickness, soil pH and organic matter levels were determined at the end of the second and third year of the study. Based upon the three years of this field study, mulching mower deposition of tree leaves, of either species, had no effect on visual quality, shoot growth, thatch accumulation, soil organic matter content and soil pH during the three years of this study. Therefore, using mulching mowers to finely grind and deposit fallen tree leaves on turf provides for an alternative tree leaf disposal method while not affecting the health and vigor of lawn turf.