Correlating Methods of Measuring Zoysiagrass Thatch

Abstract

In the absence of regular management, zoysiagrass (Zoysia spp.) thatch can be problematic and result in unacceptable turf quality. At least three methods of measuring thatch are used in turfgrass science, including organic matter percentage by weight‐loss‐on‐ignition (WLOI), depth by ruler, and mass by balance. The objective of this study was to determine if thatch compression using the faster Volk “thatchmeter” correlated to the three abovementioned methods. The four methods were evaluated as part of a field study designed to determine the influence of fertility and cultural management practices on thatch development of five zoysiagrass cultivars. Treatments were verticutting, topdressing, and fertilization arranged in a split‐split‐plot design with three replications. Thatch measurements were collected approximately every other month from June to November during three consecutive growing seasons in Jay, FL. The thatchmeter resulted in lower F values on Zoysia japonica Steud. than on Z. matrella (L.) Merr. Cultivars, indicating that the instrument had reduced sensitivity on the higher cut Z. japonica cultivars. Linear regression of the thatchmeter and the WLOI, ruler, and mass measurements resulted in 80% of the R2 values being <0.1. The increase in turf leaf blades likely contributed to the reduced sensitivity of the thatchmeter on Z. japonica cultivars. Although the thatchmeter sensitivity increased on the Z. matrella cultivars, the instrument failed to correlate to WLOI, ruler, or balance measurements.