Is there a relationship between clipping weight and volume on golf course fairways?

Abstract

Plant growth regulators (PGRs) are regularly used on golf courses to reduce mowing requirements. PGR efficacy is commonly assessed via measurements of clipping weight; however, this process is time consuming and requires specialized equipment. Golf course superintendents have started to evaluate PGR efficacy via measurements of clipping volume. Field research was conducted in Knoxville, TN, during June 2022 and 2023 to evaluate the relationship between clipping weight and volume following trinexapac-ethyl applications to hybrid bermudagrass (C. dactylon × C. transvaalensis Burtt-Davy, cv. ‘Latitude 36’) and manilagrass (Zoysia matrella, cv. ‘Trinity’ and ‘Zorro’) golf course fairways. Four experimental formulations of trinexapac-ethyl [97 g ha⁻¹ (11.4 fl oz/A)] were applied to plots 16 ft² (1.5 m²) organized in a randomized complete block design with four replications. Clippings were collected twice weekly with volume assessed via a graduated cylinder; weight was quantified after drying clippings in a forced-air oven for 48 hours. For hybrid bermudagrass, clipping weight and volume measurements returned similar conclusions regarding trinexapac-ethyl efficacy for growth regulation. On dates where both metrics resulted in treatment differences, a linear relationship was present between clipping weight and volume data (R² = 0.84). Similar responses were observed on manilagrass; however, clipping weight and volume were less closely associated (R² = 0.78). This difference could be related to growth rate, as well as clipping size and mass differences between species. Overall, results indicate that either metric could be used to study efficacy of trinexapac-ethyl for regulating growth of these species maintained as golf course fairways.