INFIELDS

Photos and graphic provided by DuraEdge Products , Inc .

By Luke Yoder and Paul Zwaska

Back in the 1960s , groundskeepers began incorporating different products into their infield skins to try to improve playability . These products were initially produced for the golf and automotive industries , and consisted of diatomaceous earth , porous ceramics and even crushed corn cobs . They were referred to as amendments or conditioners because the products were typically blended into the infield profile .

By the 1980s , calcined clays became the primary product to apply to infields , either by tilling in as an amendment or applying across the surface as a topdressing . Utilizing the calcined clay on the surface improved the sliding surface , provided a buffer between the infield mix and the athlete ’ s feet , and improved moisture management .

In 1990 , vitrified clay topdressing was introduced to the sports field management industry as an infield amendment . The clay product was baked much hotter than calcined clay , which ultimately changed its water absorption capabilities . What you had was a harder particle that absorbed much less water than calcined clays . These vitrified clays only lasted for 10 to 15 years and were eventually replaced by expanded shale , which acted very similarly to the vitrified products , except they were even more durable . The changing landscape of these products during that period left many groundskeepers confused as to what to do with their fields . It took some time for end users to understand the benefit , as there was little to no research during that 30-year span to guide the field managers in the application of these various products on their infields .

By the 1990s , the term “ infield topdressing ” became more prevalent terminology in the sports field manager ’ s vocabulary . The practice of using these products strictly on the surface — not tilling into the infield soil profile — started to change the way infield skins were managed .

Today , calcined clay and expanded shale products now dominate the infield topdressing industry . Calcined clay , with a massive amount of pore space in the particle , can absorb its own weight in water . Expanded shale has very little absorption capacity , allowing more water into the infield skin and holding it there while it acts like a mulch on the infield skin surface . Shale ’ s heavier bulk density also slows its migration on the infield surface . The different attributes of calcined clay and expanded shale are subtle to some , but can provide solid maintenance options depending on climate and labor capacity .

In the past , the terms topdressing , conditioner and amendment were used interchangeably by manufacturers and field managers to describe multiple products . The practice of tilling into the profile of the infield skin to amend or condition was preached as gospel throughout the industry . Tilling in calcined clay was the solution to every possible problem on an infield — too hard , too soft , too dry , too wet , just till in calcined and all is good . There are obvious shortcomings with a one-size-fits-all solution to multiple problems . Tilling in calcined clay to improve a poor rootzone was a good idea and still is today .

It will increase pore space , relieve compaction , increase CEC , improve vertical drainage and encourage stronger rooting for a healthier , happier turf plant . A good infield profile requires a totally different structure than a rootzone . A certain amount of compaction is essential , and , because of that , vertical drainage is virtually nonexistent . Horizontal or surface drainage is what saves games . Using calcined clay as a conditioner will compromise the structure , reduce the moisture-holding

30 SportsField Management | December 2023 sportsfieldmanagementonline . com