With the growing popularity of lacrosse, rugby and field hockey, many sports fields have added other sports to become true multiuse fields, making it more important than ever to incorporate strategies to keep turf cover later into the season. Dig into the basics of each field so you can establish a baseline to clearly define existing conditions and better fine-tune your management program. Use soil test results to provide detailed information on what is required within the soil. If the budget allows, add tissue testing for additional data on the nutrients the grass is actually using. Monitor conditions closely. Often, the watchful eye of a good turf manager will catch subtle deviations in turf quality and growth that indicate a nutrient deficiency.
Chelated iron and micronutrient combinations can be incorporated into the overall fertility program to improve turf color or vigor without spurring a burst of growth. Plant growth regulators (PGRs), applied separately or in conjunction with compatible products, can increase lateral growth and improve wear resistance
Stephen T. Cockerham, superintendent of agricultural operations for the College of Natural and Agricultural Sciences at the University of California, Riverside, says, “Build biomass in summer for fall traffic tolerance. The increase in biomass, including thatch, enhances sports traffic tolerance of the turf. In the late summer and early fall, turf biomass can be increased with applications of nitrogen fertilizers. In addition to the nitrogen fertilizer, adjust the mowing height for optimum density. That height is about .75 inch for cool-season grasses and about 5/8 inch for warm-season grasses.”
Consider changing the timing of some standard maintenance procedures to produce different results. Cockerham says, “A light to medium vertical mowing in the late summer to encourage lateral growth will increase turf density, which will improve footing and traffic tolerance.”
Anticipate potential damage and develop strategies to counteract it. Cockerham says, “Turf recovery from sports traffic injury can be increased by applying a combination of 1 pound nitrogen plus 1 pound phosphorus as P2O5 per 1,000 square feet. The application should be made in mid to late summer for maximum late-season benefit.”
As turf growth patterns change with weather conditions, adjust your procedures for optimum turf performance. “In the fall, as the temperatures decrease, plant growth also decreases,” notes Cockerham. “When the soil temperature, measured at 2 inches, drops below 50 degrees, there will be little benefit from applied fertilizer.” Microclimates vary from field to field and even across the same field, so check the temperatures at the 2-inch depth to better time applications, especially those planned for later in the season.
Consider strategies to extend the turf growing season. “Temperature modification can be used to lengthen the season for high-end sports fields. Some high-visibility sports fields have heating units built into the rootzone,” says Cockerham. While budget constraints put that option beyond the reach of the majority of facilities, there are other methods to manipulate soil temperatures. Cockerham says, “A vented plastic tarp can be used to build heat, acting somewhat like a greenhouse. The heat builds during the daylight hours, and the tarp retains heat at night. It is not unusual to raise the soil temperature measured at 2 inches by nearly 15 degrees. Venting is important to prevent smothering the turf. The temperature difference can prevent loss of color of warm-season grasses and promote overseed germination. On both warm and cool-season grasses, growth can be generated and recovery from injury can be increased.”
While full-field tarping is the best choice for overall turf consistency, it is labor intensive. If you will be replacing a worn tarp, consider recycling the useable sections of it to create smaller tarps with the specific dimensions of heavy wear areas, such as the goalmouths of soccer fields. You’ll need to monitor conditions closely, as you do with full-field tarping, but the process could be handled by one or two people, rather than a full crew.
“Overseed for color and to extend the season, particularly for high-end fields, says Cockerham. “The ryegrasses are preferred for winter overseed, either for color or covering worn areas on warm-season grasses such as bermudagrass, or for increasing density on cool-season grasses. Ryegrasses can germinate in five to seven days, with the seedlings expressing turf cover in 14 days. Traffic tolerance of the seedlings takes another two to three weeks. Perennial ryegrass is more durable than annual ryegrass. Other cool-season species can be used, but require several days or weeks longer to germinate.”
Check out the options when overseeding. New introductions in the perennial, intermediate and annual ryegrasses provide characteristics such as quick establishment, drought resistance, cold hardiness and durability that allow you to select the characteristics that best match your specific needs.
Time overseeding before games to allow players to cleat in the seed. Use seed in your divot mix for postgame repairs. Cockerham adds, “Using presoaked or pre-germinated seed are techniques that can be used to speed the process.”
Combine tarping with overseeding when possible. “Temperature is important for seed germination and seedling growth,” notes Cockerham. “Ryegrass germination will occur when daytime air temperatures are in the upper 50s, as long as there is no frost at night. At the low temperature, the time to germinate is longer.”
The tarp will be of little use for heating purposes to keep grass growing when the temperatures get to freezing levels, but it can protect the turf from desiccation during dry, cold and windy conditions.
Cockerham says, “Drainage is a major influence for sports field performance. Well-drained fields much more readily respond to late-season treatments and have greater traffic tolerance.” Identify drainage problems and explore options to correct them. Even minor changes can be beneficial. Check the degree of slope if surface drainage has been the primary method of water control on an existing field. Field maintenance procedures or minor renovations may have altered conditions. Consider including a grade adjustment to restore or improve field surface drainage as part of the next field renovation project.
In some instances, construction or renovation of areas near the field will have altered water flow patterns, either channeling water to the field from other locations or hindering the flow of excess water away from the field. You may be able to correct these situations by incorporating additional off-field drainage to channel the excess water away from the field, either into a retention area or into the facility’s drainage system.
Cockerham says, “Aerification for compaction relief is a major factor in extending the season. As the season progresses for a sports field, opening the surface by aerifying keeps the turf growing, improves drainage and helps dry the turf. Core cultivation is preferred with the cores dragged in.”
Select another method of aerification if field use schedules won’t allow the surface disruption of core aerification. “Solid-tine aerification, spiking and water jetting are also effective methods,” notes Cockerham.
Combine sand topdressing with core aerification to create sand channels to help surface water infiltrate more effectively. Increase the number of aerification passes within heavy-wear areas, or increase the frequency of aerification in these spots. A small, walk-behind aerator with multiple choices of tines gives you the flexibility to spot-aerify as needed, but even a few minutes of working a heavily compacted area with a hand-held spiker or a pitchfork can provide enough aerification to improve conditions temporarily.
Be realistic. As temperatures drop late in the season, the time and material investment required to push turf growth will no longer be cost-effective. Focus resources on maintaining the safety and playability of the field surface with the existing turf. “At that point, colorants can be used to extend the season, although they only add to the appearance and not turf performance,” notes Cockerham. “Turf that shows late-season wear or is losing color due to cool temperatures can be greened up temporarily with colorants, which may be an important detail for special events.”