Surface Stability Reinforcement and Measurement. Thomas Serensits Penn State University USA

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1 Surface Stability Reinforcement and Measurement Thomas Serensits Penn State University USA

2 Surface Stability Divoting = complete shearing (removal) of turf root system from rootzone

3 How to Increase Surface Stability? Stabilize the soil Synthetic reinforcements Artificial root system Improve plant growth Tiller density Rooting

4 Objective Evaluate the effects of 1) Synthetic reinforcements 2) Multiple application regimes of the plant growth regulator trinexapac-ethyl on the divot resistance of natural turfgrass athletic fields

5 Synthetic Reinforcement Study High-sand rootzone Perennial ryegrass (Lolium perenne L.) 3 traffic levels June to mid-october Split-block, 3 replications, ANOVA

6 Turfgrids (3, 5 g kg-1) Nike Reuse-A-Shoe Heavies and Lights(30 g kg-1) Netlon (3, 5 g kg-1) DuPont Shredded Carpet (5, 10, 20, 30 g kg-1)

7 Sportgrass

8 Divot Resistance Measurement Weighted pendulum 76 kg weight Pitching wedge head Beard and Sifers, 1990; Adams, 1997 Consistent drop height Measure divot length

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10 Mean divot lengths for the synthetic reinforcement main effect (p<0.01) 450 Divot Length (mm) 400 = Fisher s Least Significant Difference (LSD) at p < Reinforcement

11 Mean divot lengths for the synthetic reinforcements High Traffic(p<0.01) 450 Divot Length (mm) 400 = Fisher s Least Significant Difference (LSD) at p < Reinforcement

12 Synthetic Reinforcements Summary Synthetic reinforcements beneficial only after turfgrass cover significantly reduced Healthy root system masked benefits Increasing rates of reinforcement = smaller divots

13 Plant Growth Regulator Study

14 Plant Growth Regulator Study Plant growth regulator Reduce vertical shoot growth by altering hormone levels Trinexapac-ethyl (TE) Inhibits gibberellic acid Side effects increased tiller density and rooting

15 Plant Growth Regulator Study High-sand rootzone 9 cultivars of Smoothstalked meadow grass (Poa pratensis L.) 3 traffic levels July to October Strip-split plot, 3 replications, ANOVA TE (0.17 kg a.i. ha-1) application regimes (28day intervals) May through July (3) May through October (6) Cultivation treatment (May) Core aerification Vertical Mowing

16 Plant Growth Regulator Study Divot Resistance Weighted Pendulum Tiller Density Below-ground biomass Loss on ignition test

17 Mean divot length values for the treatment main effect (p<0.01) Divot length (mm) Treatment Control TE May-July TE May-Oct Cultivation LSD (0.05) 27 18

18 Mean tiller density values for each treatment (both years combined) 2000 Tillers m = Fisher s Least Significant Difference (LSD) at p < Control TE May-July TE May-Oct Cultivation Treatment

19 Mean below-ground biomass values for each treatment (both years combined) 85 = Fisher s Least Significant Difference (LSD) at p < 0.05 g m Control TE May-July TE May-Oct Cultivation Treatment

20 Plant Growth Regulator Summary TE applied May-July reduced divot size most TE applied May-October and cultivation produced inconsistent results TE applied May-July increased tiller density and below-ground biomass

21 Conclusions Synthetic reinforcements On high-use, high-sand rootzones, synthetic reinforcements can provide a decrease in divoting Plant growth regulators (trinexapac-ethyl) Preconditioning the turf before use with TE, then allowing a return to uninhibited growth, can decrease divoting

22 College of Agricultural Sciences Department of Crop and Soil Sciences