Q: What are your thoughts on rolling native soil fields to get them ready for play in the spring? Do the benefits outweigh the risk?
A: All athletes deserve a consistent, even playing surface, and, in some situations, rolling can help achieve that. First, consider the type of roller – walk-behind, ride-on, or pull-behind. Turf rollers should always have rounded edges to prevent damage to the turf. Rollers come in all sizes and weights, but are typically 300 to 2,000 pounds in weight or greater. This equates to approximately 3 to 15 pounds per square inch (psi) load applied to the soil surface and is similar in weight to vehicular traffic such as ride-on mowers. Although there is no set weight for athletic field rollers, on native soil fields the maximum recommended weight is one ton (2,000 pounds). The weight of a roller can be increased by filling the roller with water, sand, or cement. The stress at the soil surface is proportional to tire pressure, or psi. Therefore, a roller or mower with tires inflated to 15 psi will apply 12 to 15 psi pressure to the soil surface. What’s also interesting to note is that the force applied dissipates as a function of depth. For higher loads, the stress penetrates more deeply into the soil. How much stress a certain soil can withstand depends upon many factors. In particular, a soil’s ability to resist compaction depends upon soil texture (sand or native soil) and moisture content.
Rolling in the spring can smooth out uneven surfaces after winter heave or heavy traffic. Rolling cannot rectify poor grades, but is used to address minor undulations and can produce a firm surface that would be considered “faster,” which is why rolling is a common practice in golf green and soccer field management to increase speed short-term. Rolling is also utilized in sports that require ball bounce, such as tennis, cricket, and baseball. Rolling newly seeded or sodded turf areas can aid turf:soil contact and speed up establishment. Also, mowing patterns, typically created by the rear roller on a cylinder mower, can also be achieved by using a roller.
Keep in mind that rolling does not improve turf quality. In fact, overuse results in turf thinning, and quality is significantly reduced. Soils that are wet and/or frozen are susceptible to surface compaction. Using them excessively will also result in surface compaction, so it’s critical that rolled fields are regularly aerated/vertidrained. Fields that are rolled too often are more likely to become infested with shallow rooted weeds such as Poa annua and prostrate knotweed, because these weeds can survive in soils with surface compaction, whereas turfgrasses cannot. Soils that are too dry will not benefit from the impact of rolling. Furthermore, if the turf is wilted or dormant it will be severely stressed and may die, so only roll when grass is actively growing. Fields with 100% grass cover and a moderate thatch layer are less likely to be affected by rolling as a method to increase field “speed.” Also, never roll fields that have disease problems, particularly infectious diseases such as gray leaf spot, pythium, or brown patch
Whether you roll or not is a decision made on a field-by-field basis. Factors such as athlete safety and playability, soil moisture, recovery time and turf quality all come into play. In general, rolling should only be carried out “as-needed,” not routinely. This may be once per year in the spring (after winter soil heave) or several times during the playing season to keep the field safe and playable if grass cover is lost.
Pamela Sherratt Sports turf extension specialist The Ohio State University
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