ATHLETIC FIELD MANAGEMENT
Good athletic field management program produces an attractive and wear-resistant surface. Such a surface results from proper field construction, turfgrass selection, properly timed cultural practices and good judgment of field use.
In Georgia, the best and most commonly used turfgrasses for sports fields are Tifway (also called Tifton 419) and Tifway II hybrid bermudagrasses, with little difference between the two. Common bermudagrass is preferred for nonirrigated, low maintenance fields.
Proper construction produces a field with good surface and internal drainage that is more easily maintained. Therefore, field maintenance is generally easier on sandy, well-drained soils than on finer-textured soils that have high clay and silt content.
A football field should have a crown of 12 inches for sandy soils and 18 inches for clay soils from the sideline to the center or a 1 percent to 1 percent slope (Figure 1). Baseball infields should have a 1 percent slope or an eight-inch fall from the bottom of the pitchers mound to beyond the baseline (Figure 2).
Maintaining acceptable playing surfaces requires properly timed cultural practices. These practices include mowing, fertilization, irrigation, cultivation, weed control, post game repair, controlling field use, and controlling other pests like insects or diseases when necessary. A well- developed and maintained sports field can withstand extensive use.
Proper mowing promotes deep rooting and good shoot density, desirable mat and uniform growth. Regular mowing at the right height with properly-maintained equipment cannot be over-emphasized. For the hybrid bermudagrasses, (Tifway and Tifway II), a mowing height of 3/4 to one 1 is preferred, and for common bermudagrass 1 ½ to 2 inches is preferred. The first mowing in the spring should be low by as much as one-half the desired final height. This helps increase turf density and allows the cutting height to be raised during the summer if scalping occurs.
The grass should be mowed often enough so that no more than 1/3 of the leaf surface is removed at a mowing. Generally, this means the field should be cut twice a week during the summer. Higher mowing heights don't need as frequent mowing but result in lower quality and weaker turf.
If mowing frequency is properly adjusted, clippings may be returned without harming the turf. If excessive clumping of clippings occurs, they should be dispersed or removed. Reel mowers provide the best cut for bermudagrass turf. Regardless if a reel or rotary mower is used, the blades must be kept sharp and properly adjusted.
Applying fertilizer at the right time is as important as using the right fertilizer. Fertilization should be determined from soil test analysis for pH, phosphorus and potassium needs. Most turfgrasses do best when fertilized with a 3-1-2 or 4-1-2 ratio fertilizer if soil test is not available.
Most turfgrasses require 3 to 7 pounds of nitrogen per 1,000 sq. ft. per year (3 to 5 pounds in north Georgia and 4 to 7 in south Georgia). The nitrogen is usually applied at a rate of 1 pound of nitrogen per 1,000 sq. ft. per month of active growth. A typical example of a fertilizer program would be to apply a complete fertilizer (one that contains nitrogen, phosphorus, and potassium) in early spring when greenup begins, and again 2 to 4 weeks before the average first frost date. Between these times, only nitrogen need be applied as desired to maintain turf vigor. The more often a field is used, the more frequent fertilizer should be applied to maintain rapid growth for proper recovery from use.
It is very difficult to maintain an athletic field without irrigation. Irrigation should be scheduled to supplement rainfall and frequency and duration depends on environmental factors and limitations of the irrigation system.
The best time to irrigate is just before wilt occurs. Most grasses have a darker or a dull bluish green color and the leaf blades begin to fold or roll when the grass is under water stress. Irrigation should begin when these signs are first observed.
Apply enough water to soak the soil to a depth of at least 6 to 8 inches. On medium-textured soils, this usually means applying about 1 inch of water per week during the summer. Light, frequent irrigations encourage shallow, weak root systems and thatch accumulation.
The best time of day to irrigate is before sunrise because there is less wind and lower temperatures, thus less water loss to evaporation. Night irrigation is more efficient than during the day. Irrigating after dew develops or before the morning dew dries off does not increase disease problems. Irrigating 24 to 48 hours before major field use will help reduce soil compaction.
On many fine-textured soils, runoff may begin before the soil is properly wet to the right depth. When runoff occurs, stop irrigating and let the water soak into the soil for one to two hours before starting again. It may be necessary to repeat this cycle several times before irrigation is complete.
Cultivation generally includes aeration, vertical mowing and topdressing. The traffic on fields produces a compacted surface layer in the top 2 to 3 inches of the soil. This results in reduced pore space, reduced internal air and water movement and gradual thinning of the turf.
The centers of football fields, around sideline bench areas, soccer goal mouths and baseball diamond infields are good examples of areas prone to soil compaction. Even sandy soils are prone to compaction in these areas, especially when the field is used under wet conditions.
Aeration using hollow tines (coring) or open spoons are the most common means of relieving soil compaction, encouraging deep rooting and improving turf quality. Aeration is also one of the most important and most neglected practices. Coring commonly uses a machine that removes a soil core 3/4 of an inch to 1 inch in diameter to a depth of 3 to 4 inches. A core of soil should be removed and deposited on the soil surface.
There are many other acceptable aeration techniques and pieces of equipment. Frequency of aeration generally depends on soil texture and frequency of field use. Fine texture soils, fields with heavy use and fields used when wet need more frequent aeration.
As a general rule, the spacing between aeration holes should be 2 to 3 inches. This often means three passes in different directions with most aerators is necessary.
Fields should be aerified a minimum of two times per year. The first should be done in the spring just before fertilization and the second in mid summer. Each aeration should involve a minimum of three passes over the playing field. If field use is heavy or the soil is compacted, aerifying can be conducted monthly during the growing season. After the soil cores have dried, they can be crumbled and spread over the turf by using a flexible steel drag mat or some other means.
Slicing with solid blades 1/4 to ½ inch wide cultivates the soil with minimum surface disruption. Units with offset tines can be quite effective in relieving soil compaction.
Aerate when soil moisture is at field capacity. This generally translates to 8 to 24 hours after rainfall or irrigation or when a spoon-type aerator would remove soil cores to the surface. If moisture were higher or lower, cores would not easily move to the surface. However, some equipment, particularly solid tines or blades are most effective when soil moisture is drier than field capacity. Aeration should be done when the turf is actively growing and not under stress.
Topdressing is the addition of a thin layer of soil on the turf surface. Parts of the field which are used continuously tend to become depressed from the heavy use. Topdressing with a 1/8 inch layer (10.4 cu. ft. or 0.4 cu. yds. per 1000 sq. ft.) can level and smooth these areas. In addition to smoothing the surface, topdressing also reduces thatch. Topdressing after fertilization and during periods of active growth is best. Light, frequent topdressings to build up lower areas are preferred over less frequent, heavier topdressings. The topdressing soil should be of similar texture to the soil on site and can be dragged into the turf with a flexible mat.
Vertical mowing is only needed where thatch is excessive (generally thicker than ½ inch). Thinned areas should not be vertically mowed unless done prior to reseeding or overseeding and when the turf is actively growing.
High Wear Areas
Soccer fields often create special challenges because the fields are heavily used in the fall and spring, when bermudagrass is growing slowly are not at all. Obviously proper field construction is important. One technique used to address this issue is to construct fields so that sidelines can be moved two to three yards in all directions. This helps reduce wear from the linesman. Also using movable goals helps disperse traffic.
Another practice for such conditions is to use more fertilizer later in the year. This helps retain growth later in the fall and earlier in the spring. These areas also need more aeration to reduce the soil compaction. Finally, allowing the turf to grow slightly higher (up to one-half inch) in the fall should improve wear tolerance.
There is a limit to the amount of traffic even the best managed turf can stand without excessive injury. Steps which reduce management problems include the following: (1) schedule minimum use when the field is wet; (2) rotate areas of play to permit recovery of turf; (3) avoid or reduce concentrated foot traffic, such as band practice whenever possible; (4) limit or withhold use of newly-planted areas until the turf is mature and developed; (5) allow the turf to recover from winter dormancy before using it in the spring.
Since sports fields are subjected to tremendous wear and damage within a relatively short period, turfgrass cover is decreased and weeds can become a major problem. Herbicides are often needed during the playing season and in the off-season to control these weeds. Successfully controlling weeds depends upon correctly identifying the problem weed species and applying the appropriate herbicide at the correct time of the year. Weed identification assistance is available through your county Extension office.
Bermudagrass usually becomes dormant before football and soccer game schedules are completed. The cool temperatures of fall produce poor growing conditions and the turf has little opportunity to recover from use, especially in the center of the field and around the benches. The dormant or semi-dormant turf provides minimal competition to winter weeds and subsequent summer annual weeds.
A dense infestation of winter weeds can severely inhibit the early spring growth of bermudagrass. The turf will weaken and summer annuals, such as crabgrass and goosegrass, will readily invade the open areas that remain when the winter weeds die.
The most commonly used herbicides to control winter annuals in bermudagrass that is not fall-overseeded with a cool-season turfgrass are atrazine (Aatrex), simazine (Princep, Wynstar), and metribuzin (Sencor Turf). These herbicides will provide good to excellent control of annual bluegrass, common chickweed, lawn burweed, and other winter annuals. All three herbicides have preemergence and postemergence activity on winter annuals; however, metribuzin has the shortest period of preemergence activity.
Preemergence or postemergence activity enables these herbicides to be applied over a wide time period, from November through February. It is generally recommended to apply atrazine, simazine, or metribuzin after the last game. Atrazine or simazine at the recommended rate (1.0 lb. a.i./acre) applied in November and again in early February consistently provides excellent weed control. For maximum turf safety, use atrazine only on dormant bermudagrass.
Pronamide (Kerb) which also has preemergence and postemergence activity on annual bluegrass, corn speedwell and common chickweed may also be used over a similar time period on non-overseeded bermudagrass fields.
Two-way and three-way mixed herbicides contain mixtures of 2,4-D, MCPP, dicamba or 2,4-DP and may be used for winter broadleaf control in non-overseeded and overseeded bermudagrass fields. In addition to controlling winter annual broadleaf weeds, these herbicides control perennials such as plantains and wild garlic. Apply these herbicides on warm, sunny days. Two applications, at intervals of 14 to 21 days, may be required to control certain weeds. Wild garlic can also be effectively controlled in non-overseeded bermudagrass with imazaquin (Image).
Weedy grasses constitute the greatest weed problem during the summer in bermudagrass. Annuals, such as crabgrass spp. and goosegrass, and perennials, such as dallisgrass and bahiagrass, are the most common grassy weeds. Preemergence herbicides provide good control of annual grasses. However, they will not control established perennial grasses. Preemergence herbicides are recommended for use on established turfgrasses that have good density and cover.
If the field has been severely damaged from the fall or winter sports program, use only a herbicide that contains oxadiazon (Ronstar, Regalstar). Unlike other preemergence herbicides, oxadiazon does not inhibit root development from the stolon nodes of bermudagrass. Ronstar formulations may also be used at the time of sprigging bermudagrass. If seeding of common bermudagrass is planned for the field, do not apply any preemergence herbicide. Residues from a spring application can prevent the establishment of common bermudagrass from seed.
In athletic fields with large, thin, weak turfgrass areas, or on sites where renovation operations are scheduled, postemergence herbicides can control emerged weeds. MSMA or DSMA can be used to control annual and perennial grasses. Two to three applications of MSMA or DSMA are usually needed to control emerged grasses. The second application should be made 5 to 10 days after the first application. If perennial grasses show signs of recovery 3 to 4 days after the second application, apply a third treatment 7 to 10 days after the second application. On newly sprigged bermudagrass, delay applications until the sprigs are well rooted and actively growing. MSMA and DSMA will moderately discolor (yellow) bermudagrass. However, the discoloration is temporary and normal color will return one to three weeks after the last application.
Goosegrass is less susceptible than crabgrass spp. to MSMA or DSMA. A mixture of metribuzin (Sencor at 0.125 lbs. a.i./acre) + MSMA (2.0 lbs. a.i./acre) will provide good control of goosegrass. Two applications, 7 to 10 days apart are required to control established, mature goosegrass. Metribuzin can interfere with root development from the stolon nodes of bermudagrass. Do not use MSMA + metribuzin on newly sprigged bermudagrass until complete soil coverage has been achieved.
If nutsedge becomes a problem during the summer months, use either imazaquin (Image), halosulfuron (Manage), bentazon (Basagran T/O) or MSMA. The choice of which herbicide to use often depends on the species of nutsedge. For example, bentazon will control yellow nutsedge and annual sedges, but will not control purple nutsedge. Imazaquin applied alone, or in combination with MSMA, will provide approximately 6 to 8 weeks control of purple and yellow nutsedge, and other sedge species. Similar to imazaquin, halosulfuron has activity on both yellow and purple nutsedge; however, this herbicide is less injurious to bermudagrass than imazaquin. For season-long control of nutsedge, halosulfuron should be applied in two applications, each 6 to 10 weeks apart. Monthly applications of MSMA also can be used to suppress the growth of many sedges.
Two-way or three-way herbicides (2,4-D, MCPP, dicamba, or 2,4-DP) may be used for summer broadleaf weed control. Turfgrass tolerance and weed control will be better when applications are made in the late spring or early summer months when temperatures are less than 90F.
Recommendations for weed control in turf are constantly changing. The current issue of the Georgia Pest Control Handbook and the weed control calendar for athletic fields on page 5 in this bulletin will help you in selecting the appropriate herbicide.
In most cases insects and diseases are not nearly as much a problem as weeds. However if these pests do occur, contact your county Extension office for information. When using any chemical, be sure to read and follow all label directions.
Fertilizer calculations: The following
are examples of the amounts of fertilizer needed to apply one pound of
nitrogen per 1000 sq. ft.
Football Field Dimensions And Areas
Soccer Field Dimensions And Areas
SUGGESTED WEED CONTROL CALENDAR FOR BERMUDAGRASS ATHLETIC FIELDS
NOTE: ALL HERBICIDE RATES ARE EXPRESSED
ON A PER ACRE BASIS
GENERAL GUIDELINES FOR HERBICIDE USE ON ATHLETIC FIELDS
1. Use a spray volume of 20 to 40 gpa.
2. Avoid the use of postemergence herbicides at air temperatures greater than 90o F. Herbicide injury usually increases at high air temperatures.
3. Avoid the use of postemergence herbicides, simazine and atrazine during the spring green- up of bermudagrass. Herbicide use at this time can temporarily injure bermudagrass (about one month) and retard spring green-up. Use herbicides at this time only if there is a severe weed infestation.
4. The re-entry restriction, or time interval, for all herbicides that are used on athletic fields in Georgia is 24 hours. The Georgia Department of Agriculture Posting Rule - Chapter 40-21-9 requires that athletic fields be posted with a sign informing the public that a herbicide (as well as any other pesticide) has been applied to the field. Players or spectators should not be allowed to enter a herbicide-treated field until 24 hours after herbicide application. Contact the Georgia Department of Agriculture for additional information.
5. Water-in all preemergence herbicides with one-half inch of irrigation water. This removes spray residues or granular materials from the foliage and prevents player contact with the herbicide.
6. Schedule herbicide applications during periods of time that players are not using the field.
7. READ THE LABEL OF ALL HERBICIDES THAT WILL BE USED ON THE FIELD.