Shade effects on overseeded bermudagrass athletic fields: II. rooting, species composition, and traction

Shade from athletic stadium structures can be a significant detriment to turfgrass performance. The objective of this study was to determine the effects of shade on rooting and playing surface stability, measured as traction, on overseeded or non-overseeded bermudagrass (Cynodon spp.) turf. An experiment was established in 2013 on a mature bermudagrass [Cynodon dactylon (L.) Pers. cv. Riviera] turf that was either overseeded with perennial ryegrass (Lolium perenne L.) or non-overseeded. Shade structures were installed to create four light level treatments, including 0%, 30%, 60%, or 90% light-reducing shade cloth. The light treatments resulted in average daily light integrals (DLI) of 40.8, 26.2, 14.8, and 3.3 mol m–2 d–1, respectively. Data were collected on rooting characteristics, species composition, and two forms of traction measurements. Moderate levels of shading (30%) caused a significant decline in rooting characteristics in non-overseeded turf, while rooting of overseeded turf was not significantly affected until a 60% light reduction. Rotational resistance and peak horizontal force, measurements of athlete traction, were affected by increasing shade in both overseeded and non-overseeded turf, but the association between traction and a minimum DLI was not conclusive. The persistence of bermudagrass in overseeded turf was significantly reduced at all shade levels studied. This study clearly demonstrates that rooting, bermudagrass persistence and traction of overseeded and non-overseeded bermudagrass athletic fields are negatively affected by even modest levels of shade.