Realistic traffic simulation is crucial to the validity of athletic field research. Previously developed athletic field traffic simulators contain studded drums that turn at different speeds, creating shear forces at the playing surface. The Cady Traffic Simulator (CTS) (a modified walk‐behind core cultivation unit) was developed at Michigan State University in 2000. The objective of this study was to compare the magnitude and direction of the forces produced by two traffic simulators: the Brinkman Traffic Simulator (BTS), a pull‐behind unit, and the CTS. Both simulators were operated over an in‐ground force plate, which measured the forces in three directions: front to back, side to side, and vertical. The CTS produced a higher compressive stress and net shear stress when operated in either direction than the BTS. The average peak compressive stress produced by the feet of the CTS when operated in the forward direction was approximately 30 times higher than the combined compressive stresses of both BTS drums. The average peak net shear stress produced by the feet of the CTS when operated in the forward direction was approximately 15 times higher than the combined net shear stresses of both BTS drums. Operating in the reverse direction, the average peak compressive stress produced by the feet of the CTS was greater than five times the compressive stresses of both BTS drums combined. The average peak net shear stress produced by the feet of the CTS was approximately four times higher than the combined net shear stresses of both BTS drums.

Many organic products have been used effectively in turfgrass management progranns, but their exclusive use in athletic field maintenance and effect on playing surface quality has not been extensively researched. The objectives were to determine the effects of management regimes and overseeding during simulated traffic on (i) turfgrass color and quality, (ii) percent cover, and (iii) weed populations. The experimental design was a 2 X 6 factorial, with two overseeding levels (overseeded and not overseeded) of a perennial ryegrass (Lolium perenne L.) blend during traffic and six management regimes: (i) conventional, (ii) organic manure (OMan), (¡ii) organic protein (OPro), (iv) organic manure plus compost tea (OMan+GT), (v) organic protein plus compost tea (OPro+GT), and (vi) none or the control. This research was conducted over 2 yr on a mature stand of 'Lángara' Kentucky bluegrass {Poa pratensis L.) on a Paxton sandy loam soil. Fall traffic was simulated with a Gady Traffic Simulator. The conventional treatment consistently produced higher quality turfgrass, lower weed counts, and better mid-to late-fall color. Weed populations were significantly less with the conventional regime. Overseeding increased cover at the end of the traffic periods by 32% in the first year and by 103% in the second year. Overseeding was also beneficial to turfgrass color and quality and in reducing weeds. The conventional treatment also retained significantly higher turfgrass cover than the organic regimes under trafficked conditions late into the fall in 2008. However, no difference in late fall cover between the conventional and organic management regimes was observed in late fall 2009. Gompost tea applications showed no enhancement of turfgrass color, quality, or cover over the entire duration of the study.

The Brinkman Traffic Simulator (BTS) has been a useful tool to simulate sports field traffic. However, rate of traffic stress produced by the BTS, a pull‐behind unit with two differentially connected studded rollers, has been questioned. The Cady Traffic Simulator (CTS), a modified walk‐behind core cultivation unit, was developed and tested to potentially produce more aggressive traffic stress. A comparison study was initiated between the BTS and CTS to evaluate these simulators on a Kentucky bluegrass (Poa pratensis L.) stand. Playing surface data collected were surface hardness, traction, soil moisture, bulk density, porosity, and plant counts. Higher surface hardness, lower traction, and lower plant count values resulted when the CTS applied 10 passes per week (PPW) compared with other treatments. Surface hardness, traction, and bulk density values were statistically similar when the CTS applied 2 PPW, and BTS applied 10 PPW.

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Sands used to construct athletic fields and golf course putting greens are characterized in laboratory tests to evaluate their suitability before construction. Many of these tests provide quantitative measurements of soil physical properties; however current evaluation procedures for particle shape rely on subjective visual assessments. The objective was to quantify differences in the particle shape complexity of sands using a dynamic, digital image analyzer, the Camsizer, and correlate those values to current quantitative and qualitative methods of particle shape analysis. The Camsizer uses two cameras to capture images of randomly falling particles at a rate of 60 frames s−1 These images are analyzed and shape parameters such as sphericity and aspect ratio are calculated. Five monosize sands of varying shape were evaluated, as well as a rounded and angular control. The dynamic method showed significant differences between sphericity and aspect ratio values of all sands, indicating these parameters can be used to quantitatively assess particle shape complexity. The values obtained with the Camsizer and with a well accepted static, quantitative technique that uses light microscopy were correlated for both aspect ratio (r = 0.935) and sphericity (r = 0.982). The Camsizer values also exhibited a positive relationship with the qualitative shape parameters, sphericity, and angularity. The coefficient of variation values for the aspect ratio and sphericity data, as determined by the dynamic method, were significantly lower than the static method or the qualitative analysis. These results indicate that this digital imaging analysis tool provides an accurate, objective means of quantifying particle shape complexity.