Abstract
Thatch is an intertwined layer of dead and living stems and roots that accumulates in turfgrass when organic matter production outpaces decomposition, affecting turfgrass quality and playability. This study evaluated thatch accumulation and performance of various zoysiagrass (
Zoysia
spp.) genotypes across six locations (Olathe, KS, USA; Stillwater, OK, USA; West Lafayette, IN, USA; Dallas, TX, USA; and Davie and Citra, FL, USA) for the National Turfgrass Evaluation Program (NTEP) and United States Golf Association (USGA) trials. Thatch accumulation in the NTEP trial was measured 5 years after planting, while the USGA trial was assessed 3 years after planting. The objectives were to 1) evaluate thatch accumulation across cultivars and breeding genotypes and 2) evaluate the correlations between zoysiagrass thatch depth vs. other genotype morphological traits. Thatch depth, thatch mass, turfgrass quality, and other traits were measured across locations. In the NTEP trial, significant differences in thatch depth among cultivars were observed only in Dallas, TX, where ‘Emerald’ had the highest thatch depth (0.73 inch) and ‘Meyer’ and DALZ 1808 had the least (<0.35 inch). The USGA trial showed no significant thatch depth differences in Olathe, KS, and West Lafayette, IN, but minor variations were noted in Citra, FL. Correlations between thatch depth and other traits showed that thatch depth was negatively correlated with surface firmness at Dallas, TX, and Citra, FL, locations (NTEP trial) and with Normalized Difference Vegetation Index (NDVI) in West Lafayette, IN (USGA trial). Positive correlations with thatch depth were found with tiller numbers in Stillwater, OK; Dallas, TX; and Davie, FL (NTEP trial) and were positively correlated with the thatch mass in Olathe, KS (USGA trial). Environmental conditions could impact the performance of zoysiagrass genotypes, although these conditions were not considered in this study. The correlations noted at each location give guidance on what may impact thatch development or its influence over time.