The Sportsturf Quality Manager at the Greece Super League has issued a warning about Black Layer in football turf, and, in particular, hybrid turf surfaces. According to Antonis Grimotsis, managing this phenomenon is significantly more challenging in hybrid turf surfaces.

Black Layer can undermine the performance of both natural turf and hybrid turf surfaces. The phenomenon is a subsurface accumulation of metal sulphides, formed when hydrogen sulphide reacts with metals like iron under anaerobic (low-oxygen) conditions. “It typically develops in the soil beneath the turf and appears as a black or grey layer that severely restricts water infiltration and air exchange,” Grimotsis explains in a post on his LinkedIn profile.

Particularly concerning for hybrid turf systems
As hybrid turf systems rely on precise water management and a healthy root zone to maintain their unique balance of natural and synthetic components, Black Layer is a particular concern for this type of surface.

“The inability to use hollow core aeration on hybrid turf systems undoubtedly is a significant cause of Black Layer development compared to fully natural surfaces,” Grimotsis claims. As compaction levels can be significantly higher on stitched surfaces, compared to any other type of surface, preventing Black Layer from forming can be particularly challenging.

According to the Sportsturf Quality Manager, when Black Layer develops, it will drop in drainage efficiency. The resulting waterlogged conditions will impact root health and microbial activity. Subsequently, root growth will stifle and shallow root systems compromise the natural component of hybrid turf. The final result will be a reduced playability as the surface becomes uneven, softer, and less predictable. This directly affects ball roll, bounce, and player performance.

Preventing and managing Black Layer

To prevent and manage Black Layer in hybrid surfaces, Grimotsis advises to strategically and frequently aerate. This will maintain air circulation and prevent anaerobic conditions. This is especially crucial for stitched systems, where the synthetic structure can limit soil aeration.

Furthermore, topdressing is of importance to dilute organic matter and enhance drainage, reducing the likelihood of Black Layer formation. Optimising water management is another crucial step. One should avoid overwatering and ensure the subsurface drainage system operates efficiently. At the same time, water distribution must be improved. This can be achieved by using a wetting agent to improve water penetration and distribution in the soil profile. However if anaerobic conditions are already present, wetting agents alone will not eliminate the problem; additional measures such as aeration and improved drainage are essential.

Last but not least, Grimotsis advises soil testing and monitoring. Soil oxygen levels, organic matter, and water movement should be assessed regularly to identify early signs of anaerobic conditions.