Potassium Nutrition Effects on Agrostis stolonifera L. Wear Stress Tolerance

Intensively used turfs, like golf course putting greens, are exposed to wear injury. Creeping bentgrass (Agrostis stolonifera L.) has only moderate wear resistance compared to many cool and warm season turfgrasses. There is the possibility of improving wear tolerance by manipulating plant nutrition. With this in mind, a series of experiments were conducted to evaluate the effects of potassium nutrition levels on A. stolonifera wear tolerance and associated plant characteristics. These experiments were conducted at the Michigan State University Turfgrass Research Center in East Lansing, MI and the University of Nebraska-Lincoln John Seaton Andersen Turfgrass Research Center located near Mead, NE, USA. A randomized complete block experimental design with four replications was used in all experiments. Potassium nutrition treatments were 0, 20, 30 and 40 g K m⁻² season⁻¹ with a plot size of 2.5 × 10 m. Potassium sulfate (0-0-41.5K) was used as the K-source. Potassium treatments were applied in eight equal applications made every three weeks during the growing season. Turfgrass wear tolerance, leaf tissue potassium content, shoot density, verdure, load bearing capacity (LBC), leaf blade tensile strength (LBTS), relative turgidity, tissue moisture content and cell wall constituents were determined. Potassium nutrition levels increased wear tolerance linearly with an increase >40% between the untreated control and the 40 g K m⁻² season⁻¹ treatment. Wear tolerance was correlated (r=0.93) to LBC. Potassium nutrition levels increased total cell wall (TCW) content of plant tissue. Tissue moisture content was negatively correlated to TCW (r=−0.89) and tissue K-content (r=−0.90). These results support the role of K-nutrition in improving turfgrass wear tolerance of A. stolonifera. Improvements in TCW content, LBC, and LBTS appear to be important factors contributing to the increased wear tolerance. Turfgrass managers have the opportunity to manipulate potassium nutrition for turfgrass wear stress tolerance improvement on intensively used turfgrass sites, like golf course putting greens.