Mississippi Turfgrass Association – Michael Richard, Mississippi State University, Turfgrass Extension Associate
Across Mississippi, youth of all ages are enjoying America’s greatest past times. There’s no denying that sports are interwoven into the fabric of who we are as a nation. Some of my fondest memories as a child were made on the baseball, football, or soccer field. In my current role, I have the pleasure of visiting high school sports fields across Mississippi. The coaches and field managers I meet have a great passion for providing the best playing surface for their athletes. They juggle several job responsibilities and have limited budgets – making field maintenance a difficult task. In my travels, I have noticed some common maintenance practices that are lacking or in need of correction.
Compacted soils may be the biggest constraint to proper turfgrass growth. Compaction occurs from excessive traffic that compresses soil particles, which restricts water and air movement through the soil profile. Turfgrass roots may be unable to penetrate the soil, which decreases turfgrass resilience to wear. Soil of our sports fields must be physically modified to relieve compaction, either modestly on a yearly basis, or more aggressively on a less frequent basis. The most effective way to do this is through annual aerification and topdressing. Aerification involves removing or loosening soil to relieve compaction, which improves drainage and increases water and air infiltration to turfgrass roots. This is best accomplished with a hollow tine core-aerifier that pulls soil plugs (Figure 1). Core aerification is most effective in conjunction with sand topdressing. Applying 1/8 to 1/4 inch of coarse sand during or immediately after core removal will fill the holes and help alter soil structure (Figure 2). Sand topdressing aids in making the aerification process last longer. Both of these processes should take place when the turfgrass is actively growing to help it recuperate more quickly.
Mowing is the most important, but often most mismanaged, aspect of sports field management. A properly mown sports field promotes lateral turfgrass growth, which increases shoot density and provides a denser turfgrass canopy. Mowing height and frequency directly impact the playability of sports fields. Hybrid bermudagrass sports fields perform best when mown between roughly 0.75 to 1.0 inches in canopy height. When bermudagrass is mown above these heights it becomes puffy and less wear tolerant (Figure 3).
Correct mowing should never remove more than one third of the leaf blade. For example, if target mowing height is 1 inch, we mow when the grass reaches 1.5 inches. Depending on temperature, fertilization, and irrigation, fields may need to be mown every 2 to 3 days during summer months (an amount that many low-maintenance field managers are not comfortable with). An easy way to know if your mowing practices are adequate is by checking the turfgrass color. The grass should be green from the soil surface to the tip. Brown stems indicate improper mowing – generally too high and infrequent. Gradually decrease mowing height over the course of two weeks to avoid scalping the turfgrass. Properly aerified and topdressed fields should allow mowing, even when conditions might otherwise be too wet. If fields are not able to be mown during wet conditions, we must raise mowing heights or plan on removing clippings in order to prevent thatch accumulation.
The cornerstone of any agronomic program is a soil test. When we visit a doctor, they check our vitals to get a baseline of our current health. Analogously, a soil test is a checkup for your field’s soil chemical health. A basic soil test measures pH and nutrient levels. Soil pH is measured on a 1 to 14 scale, with 1 being highly acidic, 14 being highly alkaline, and 7 being neutral. Bermudagrass grows best at a pH between 6.0 and 6.5. If the soil test reveals an acidic soil (less than 5.8), limestone should be added to raise pH. Unless soil pH is low, lime is not generally recommended. If soil pH is high, it may be due to some underlying soil characteristics that are not always easy to solve. Sometimes in extreme circumstances, elemental sulfur is applied to acidify excessively alkaline soils, but routine fertilization and topdressing generally counteract alkaline conditions, so sulfur is less commonly recommended. Routine fertilizer applications should also be based on soil test results. Excessive nutrients are wasteful, decrease plant health due to excessive growth, and may be harmful to the environment. Most soil test results provide recommendations for improving pH and for replacing deficient nutrients. Soil tests are provided through Mississippi State University Extension Soil Testing Laboratory.
Accurate Sprayer Calibration
Calibrating a sprayer involves selecting the proper nozzles, pressure, and speed of travel. There are several different ways to accurately calibrate a sprayer, but the simplest is the 1/128th acre method, also called the “baby bottle” method. The spray collected from a single nozzle measured in ounces directly converts to gallons per acre regardless of the number of nozzles on the boom. Because there are 128 ounces in a gallon, the ounces collected from 1/128th of an acre will equal gallons of solution per acre. Follow the 10 easy steps below to avoid needless chemical waste, improper application, and potential turf injury.
- Fill sprayer with water. Use only clean water to calibrate sprayer.
- Measure the distance (in inches) between nozzles on the spray boom. If your sprayer has only one nozzle, this number equals the expected spray width. Refer to the chart on the opposite page to obtain a test course distance (in feet).
- Measure the course distance (in feet) according to the chart and flag it for easy visibility.
- Drive or walk the test course at an acceptable spraying speed with the sprayer on. Make note of the engine RPMs, and most importantly, record the seconds it takes to travel the measured distance between the two flags. Be sure to take a “moving start” to the beginning flag, and continue moving beyond the ending flag to maintain a uniform speed within the flagged distance.
- Park the tractor/sprayer, set the brakes, but keep the engine RPMs at the same setting used to drive the test course.
- To check the uniformity of all nozzles on the boom, collect the spray from each nozzle for exactly 1 minute. If the flow rate of any spray tip is 10 percent greater or less than that of the others, replace it. Whatever the type of sprayer tips you use, be sure they are all the same type. Make sure strainers are present within the nozzle body, as the absence or presence can significantly impact tip output. Strainers also protect spray tips and prevent clogging.
- Make any final sprayer pressure adjustments (this will vary with the type of spray tips you use and the gallons per minute you wish to spray through them).
- Using a plastic measuring container that is marked in ounces, collect the water sprayed from one nozzle for the same amount of time it took to drive the test course.
- The amount of water collected in ounces will equal the gallons applied per acre.
- Last, but not least, be sure to read all product labels for proper application information.
For additional information, you can access the Mississippi State University Extension Publication 2086 – Managing Mississippi Sports Fields online at extension.msstate.edu.
Michael Richard is an Extension Associate at Mississippi State University. He coordinates the Mississippi Sports Field Maintenance Clinics – a MSU Extension program designed to assist low-maintenance sports field managers with providing safe playing surfaces for Mississippi youths. He resides in Starkville, MS with his wife and four children. His hobbies include hunting and RV’ing.READ THE ISSUE