SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
Issue link: https://read.dmtmag.com/i/141613
FieldScience It may take a couple of years to see the benefits of dressing with sand. Obviously, the more sand applied, the faster the desired 70% by weight goal will be reached. It is not a good idea to apply more than 0.25 inch at any one time as the sand can be abrasive to both turf equipment and the grass, but two or three applications could be made each year, outside of the playing season. If there is money and manpower available, a new "fast-track" sand build-up system could be employed. This system was recently developed by Michigan State University and can be accessed through their website. In addition to improving the rootzone soil, there are several drainage options for fields: Surface Drainage refers to the ability of water to shed or run off the surface due to the installation of a slope or crown. The severity of the slope or crown depends upon the amount of sand in the rootzone. Fine textured soils with <45% sand should have crowns/slopes of 1.5 - 2 % while rootzones with >70% sand can have smaller crowns/slopes of 0.75 – 1.0 %. For a more detailed guideline on this, refer to ASTM WK37583 – New Guide for Construction or Renovation of Native-soil Athletic Fields. Internal Pipe Drain: The origin of this type of installation is in agriculture and it is relatively cheap to install. It consists of a grid of piping below the surface of the subsoil. The benefits are (1) the gradual lowering of the water table and (2) shorter drying time. However, this system is not accustomed to dealing with high volumes of water in short periods of time, such as during a game. Also the area affected by the drainage pipes is usually restricted to within a few feet or so of the pipes. The main objectives of pipe drainage is to lower water tables, control or cut off flow of extraneous water, and drain any surface water directed to them.. The disadvantages to this system are that the water must flow to the drains in order for them to be effective. Slit Drains: Slit-drained fields are designed so that surface water bypasses the native soil, and the local soil has less of an influence on drainage rate. A common specification is to install sand slits 1-inches wide, 10-inches deep, on 3 ft. spacing (Fig- 16 SportsTurf | July 2013 ure 7). Most importantly, the slits must transmit surface water through the native soil surface to a more permeable material underneath - such as a gravel layer or permeable fill over pipe drains. The slits run perpendicular to the pipe drains. Two problems can occur with slit drained fields: (1) when the permeable material does not come into contact with the sand slit (i.e. there is a soil layer between the sand slit and the underlying permeable material), or (2) when the slit is not kept directly at the field surface and the slit is sealed off by adjacent native soil. This can occur rapidly, even during one game if field conditions are very wet. To prevent the latter, a heavy annual sand topdressing program has to be initiated to make sure that the slits are not "capped off " over time. Research by the STRI has indicated that these types of field can accommodate 6 hours adult play per week (95-125 events per season). In addition, they have suggested that, if managed correctly, a slit-drained field should last about 7 years before needing to be slit again. Suspended Water Table (USGA, PAT system or similar): By far the most expensive of the options to install and maintain, the suspended water table (SWT) construction consists of internal drain pipe, a gravel blanket and a sand rootzone. The biggest benefit is that it resists compaction and has very high infiltration rates. The challenges are that they require greater input (water, fertilizer) and they can lose grass cover quickly from over-use if the sand is not stable, or if regular over-seeding and topdressing is not performed. Organic matter accumulation is also a challenge. Switching from a native soil field to a SWT field is not economically viable in many cases and can only really be justified from a financial point of view if play has to be guaranteed irrespective of the weather (except snow and frost). OTHER NATIVE SOIL FIELD IMPROVEMENTS Moving on from discussing the intricacies of removing water quickly from soil fields, adding water to soil fields is also an important part in native soil field improvement. Irrigation is undoubtedly the most underused management practices on native Figure 7 Figure 8: This new field was constructed in the spring and then not irrigated during the summer. The football season then had to be played at another location. soil fields, especially during renovations or overseeding/sodding operations. It is highly unlikely that turf will recuperate from wear or that new seedlings will survive if supplemental water is not added to the field during drought (Figure 8). Even in Ohio, with 40-inches of precipitation per year, it is not uncommon to have drought conditions June, July and August. Adding water to a field does more than grow healthy grass, but can significantly reduce surface hardness on fine textured, dry and compacted soils. Dry and compacted native soil fields can have Gmax (hardness) readings in excess of 400, which is four times harder than recommended for athlete safety. And with the CDC reporting that 135,000 children between the ages of 5 and 18 are treated each year for concussion and other head injuries, it is best to make sure that the playing surface is not one of the contributing factors. Guidelines for best management practices on native soil fields, like mowing, regular and timely applications of fertilizer, over-seeding etc. can be found through the STMA website or University turfgrass program website. For example, Ohio State has a free factsheet entitled "Standard Guide for Maintaining Sports Fields and Recreational Turf in Ohio." n Pamela J. Sherratt is the sports turf extension specialist for the turf program at The Ohio State University in Columbus. www.sportsturfonline.com