Carbon accumulation of cool season sports turfgrass species in distinctive soil layers

Abstract Carbon sequestered by turfgrasses may contribute to reducing atmospheric CO2 levels, to improved soil health, and to increased turfgrass quality. The objective of this study is to compare the amount of soil C accumulated by nine cool season turfgrass monocultures and 12 mixtures of turfgrass species during the first 3 yr of establishment. Thatch, mat, and other soil layers were sampled and thickness of these layers was quantified in a field study conducted in the Netherlands. From these samples, dry matter, C and N concentrations, and C/N ratio were measured. Festuca rubra spp. and Poa pratensis had a thicker thatch layer than Lolium perenne, Festuca arundinacea, Festuca ovina, and Agrostis stolonifera. Lolium perenne had a thicker mat than Festuca rubra spp. Mixtures of turfgrass species and subspecies seemed to vary more in thatch and mat thickness, as well in the total thickness of both layers combined, than did monocultures. Thatch thickness but not mat thickness correlated to C accumulation in the soil, and this accumulation in the top soil till 20‐cm deep was species dependent. The highest amount of C accumulated in Festuca rubra spp. monocultures, whereas the smallest amount was found in soils with Lolium perenne. Thatch of Festuca rubra spp. showed high C accumulation with high C and N concentrations, whereas in Lolium perenne and Poa pratensis monocultures low C accumulation was related to low C and N concentrations. Only for Festuca rubra spp. and Poa pratensis, C/N ratios partly explained variation of C accumulation with soil depth.