Carbon Sequestration Under Warm Season Turfgrasses in Home Lawns.

Turfgrass cover in the U. S. is expanding because of increasing urbanization and the addition of approximately 675,000 ha of residential property every year. Such perennial grass covers could have a significant effect on the soil carbon (C) cycle. Despite its large-scale presence in the urban ecosystem, the role of turfgrasses in C cycling in home lawns in southeastern U. S. soils has not been documented, and studies in warm-season turfgrasses are lacking. The objective of this study was to estimate C sequestration in soil as affected by turfgrass species including: bermudagrass (Cynodon dactylon x C. transvaalensis), centipedegrass (Erecholmoa ophroides Munroe Hack.), and zoysiagrass (Zoysia japonica Stued.). The study was initiated in summer, 2012 on loamy sand and sandy loam soil textures (fine-loamy, kaolinitic, thermic Typic Kanhapludults). Eighteen lawns were sampled, six lawns of each grass species (three of each soil texture), with the harvested grasses separated into stems (rhizomes and/or stolons), above ground biomass (verdure), and belowground roots. Underlying soil samples (0-5, 5-10, and 10-20 cm) were also collected. Total C concentration was determined on finely ground oven-dried samples by combustion. Results showed an accumulation of organic C in the top 20 cm of the soil profile in sandy loam soils. These results indicated that C sequestration in soils have increased from 3.8±0.2 (bermudagrass) to 5.3±0.6 (zoysiagrass) kg m^-2.