More Americans get screaming notices for unsatisfactorily mowed front lawns than parking tickets. They may not be batshit crazy about football or soccer, but Americans can get ridiculously pedantic and particular about their front yard grass or turf lawns.
So when FIFA faced a knotty issue – eight of the sixteen stadiums hosting the World Cup were designed for artificial turf—and FIFA only used natural turf, USA’s ace grass experts were summoned. The University of Tennessee (UT), Knoxville’s world-renowned turfgrass experts led a first-of-its-kind research collaboration with Michigan State University and FIFA, the global governing body for soccer, to set up the pitches.
While the uneven bounce at Pan-Am drew criticism, the UT were confronted with the eventual question. “How can a soccer ball bounce the same on a pitch in Vancouver, Canada, and in Mexico City?” the UT website writes. So through a five-year research project, UT’s expert turfgrass team developed turfgrass systems along with irrigation, maintenance, and testing methods to produce identical pitches that were same and safe for players.
‘Two of these systems include conventional rootzone and shallow profile. Conventional rootzone systems are typically found beneath high-end, natural turf fields. But eight of the sixteen stadiums hosting the World Cup are designed for artificial turf—and FIFA only uses natural turf. That’s where the shallow profile system comes in. Instead of a gravel base layer used in the conventional rootzone system, the shallow profile system uses permavoid and geotextile materials,’ the website writes.
Bermudagrass, the turf itself for warm climes, is well known to all American home owners, and the Sod is the top layer of both turfgrass systems. For cooler climes, it’s a mix of Kentucky bluegrass and perennial ryegrass.
The website elaborates: ‘A method known as hybrid stitching provides additional stability by reinforcing the pitch with fibers. The rod method of stitching, used for most outdoor stadiums and some indoor stadiums, injects reinforcing fibers into the soil as the grass grows. Some pitches for both domed and one outdoor stadium are grown using the carpet method, in which seeds are planted directly into a layer of fiber-reinforced soil, allowing the grass to grow into the stitching.’
The middle layer is a sand rootzone. It allows for more consistent footing and surface firmness. It reduces compaction compared to native soil fields and supports healthier turfgrass growth by allowing for more air and water movement, they elaborate.
Conventional rootzone systems have the Gravel base which allows for quick water drainage while retaining enough moisture to promote healthy root growth. Drainpipes move excess water away from the pitch. UT informs that all FIFA World Cup 26 stadiums are equipped with an in-ground irrigation system with sprinkler heads that can emerge and water the entire pitch. They also have a vacuum ventilation system to assist with water drainage
The unique feature however is the Shallow profile system. The UT website explained how instead of the traditional gravel, the shallow profile system used permavoid and geotextile materials.
Geotextiles were a plastic woven sheeting that rests on top of the permavoid, the geotextile layer prevents sand from filling the openings in the permavoid and helps regulate moisture by allowing excess water to pass through. The Permavoid, UT explained, was the base layer of the shallow profile system — a high-strength modular interlocking plastic structure that allows for adequate water drainage and can be more quickly removed than gravel when a pitch is temporary.
Besides an in-ground irrigation system with sprinkler heads that can emerge and water the entire pitch, FIFA will also have a vacuum ventilation system to assist with water drainage.
