Andy McNitt, Ph.D. candidate in agronomy

Public participation in sports, both recreational and on organized teams, is skyrocketing. Overuse of sports fields often leads to compaction of the soil beneath them and can quickly wear out the turf. "When this problem was first recognized on playing fields," Andy McNitt says, "the industry borrowed from golf courses the idea of making putting greems with a sand base. But when they added sand to playing field soil, the surface became prone to divoting and the turf wore out quickly. So next the playing field industry borrowed an idea from civil engineering, which involved supplementing the sand with fiber materials the same size as the pore space between sand grains. Well, this wasn't ideal either because although the divot resistance increased, the surface was so hard that players were getting injured more often." Through his Ph.D. research, McNitt tried to determine what type of soil inclusions support the most wear-resistant turf, yet provide a surface that is soft enough to minimize player injury.      With the guidance of Dr. Pete Landschoot, associate professor of turfgrass science, and help from Dr. Donald Waddington, professor emeritus of soil science, McNitt tested the effectiveness of various manufactured and recycled products as inclusions in playing field sand. The recycled materials included ground-up, used Nike sneakers and DuPont shredded carpet filaments at various percentages. He also examined the properties of sand mixed with Sportgrass, Turfgrids, and Netlon, products manufactured for this purpose.      Generally, materials that made the surface softer increased turf wear resistance. Those that hardened and compacted the surface were least resistant to football-type wear. McNitt found that all but one of the tested materials, DuPont shredded carpet, produced at least one negative characteristic for playing field applications.

The shredded carpet decreased the soil bulk density, making it softer for players to fall on and increasing wear resistance, but it was also divot-resistant.      McNitt's research has facilitated the commercialization of modular turf systems that can be laid down temporarily or permanently. Sand is mixed with recycled carpet filaments to support cut sod from which the sand won't fall out when it's moved. This turf allows flexibility to rotate, replace, and rehabilitate worn grass areas and is ready to play on just a few days after installation. This system was recently installed at PSINet Stadium, home of the Baltimore Ravens professional football team.      In January, McNitt will begin a position as assistant professor of soil science-turfgrass. He intends to expand his research program on ideal athletic field surfaces. "I hope we can eventually determine what mixture of sand, soil, and organic material will provide the best playing surface for athletic fields so that we can minimize the reliance on synthetic reinforcements," says McNitt. He also hopes to continue developing a working relationship with the National Football League and various other national and statewide professional and recreational athletic organizations. He coordinates an internship program with the NFL for turfgrass undergraduates.      McNitt has been a faculty instructor in the department since 1998. He has been part of the team developing courses for the Penn State World Campus turfgrass management certificate program. He can be reached by e-mail at asm4@psu.edu or by phone at (814) 865-6541.      The sand inclusions study was funded by the Pennsylvania Turfgrass Council, DuPont Nylon, Nike, Inc., and Sportgrass, Inc.