Effect of Crumb Rubber Topdressing on Athletic Fields:

Pilot Study

D.K. Tompkins, J.B. Ross and D.L. Moroz

Introduction

A pilot study was established in 1997 on an athletic field in Edmonton (Austin O’Brien High School) to determine the effect of using crumb rubber topdressing.

In western Canada, athletic fields receive considerable traffic in the late fall and during the winter from various sports activities. During this time, the turf is in a dormant state due to the cold temperatures and is unable to recover from heavy use. It was hoped that the use of crumb rubber would improve both resiliency and wear tolerance (resulting in improved area cover in the spring). Results of this pilot study showed that both of these factors were improved with the use of crumb rubber topdressing. Consequently, a more in depth study was initiated in 1999 on two athletic fields in Edmonton.

There was, however, concern about the potential for zinc from the crumb rubber to have a negative impact on turf quality. This was a particular concern for turf receiving multiple applications of crumb rubber. Consequently, this pilot study was extended for an additional year in order to evaluate a second application of crumb rubber.

Materials and Methods

This experiment was established in 1997 in a Randomized Complete Block Design with four replications of each treatment. Treatments included four different crumb rubber depths: 0 mm, 6 mm, 12 mm and 18 mm. In the summer on 1999 the original plots were subdivided into two and a second application of crumb rubber was made on one subplot.

Area cover, turf density and turf colour were monitored using a 1-9 scale. Non-replicated soil samples were taken from each treatment to determine soil zinc levels. These samples were taken on three occasions: mid-July (just prior to the second application), mid-September and Mid-October.

Results and Discussion

A second application f crumb rubber had no significant impact on area cover (Table 1), turf density (Table 2) or turf colour (Table 3). The second application showed no negative impact on the measured quality factors.

Table 1: Effect of crumb rubber depth and number of applications on area cover at Austin O’Brien.

¹Within a column, for each source of variation, numbers followed by the same letter are not significantly different at p=0.05.

Table 2: Effect of crumb rubber depth and number of applications on Turf density at Austin O’Brien.

¹Within a column, for each source of variation, numbers followed by the same letter are not significantly different at p=0.05.

Table 3: Effect of crumb rubber depth and number of applications on Turf colour at Austin O’Brien.

¹Within a column, for each source of variation, numbers followed by the same letter are not significantly different at p=0.05.

The soil zinc levels were similar on July 15, prior to the second application (Table 4). However, by mid-September, there was a dramatic increase in soil zinc levels associated with increasing crumb rubber depth. By mid-October, this effect had largely disappeared. It is possible that the increase in soil zinc is only a temporary effect. Perhaps, the increase in soil zinc is coming from finer particles that are quickly leached. If this is the case, it may be possible to wash the crumb rubber prior to application and eliminate the problem.

Table 4: Effect of crumb rubber depth and number of applications on soil zinc (ppm) at Austin O’Brien.

Summary

A second application of crumb rubber did not negatively affect turf area cover, density or quality. The level of soil zinc temporarily increased. However, by the end of the season, there were only relatively small differences among the crumb rubber treatments. Also, the difference between soil zinc levels in the one and the two applications was minimal.