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/506886
50 SportsTurf | May 2015 www.sportsturfonline.com Our bermudagrass has not yet come out of dormancy. Is it ok to aerify? We normally aerify in June and August but thought the extra aerification would be good for the fields. We would be using ½-inch hollow tines and picking up cores, then leaving the holes open. Labor-wise it is a good time for us to do this since we are not so busy with mowing. Also, the field is not being used heavily for the next several weeks. STMA member from Western NC T his is an excellent question that often comes up during the winter. The simple answer that I often tell people whenever they ask if they should aerify is yes, since a turf manager cannot aerify too much. I say that mainly because most field managers do not aerify enough. I generally encourage aerification and more aerification. Unfortunately in this case the answer is not so simple. But before I address timing, I would like to address frequency. Some of you may be familiar with Jerad Minnick, former head groundskeeper at a 22-field soccer complex in Boyds, MD. The last few years he has spoken at a number of turfgrass conferences. If you have not heard him at one of those, perhaps you have read his popular blog (growing- greengrass.net). He is a huge proponent of using natural grass and he has proven his philosophies can work considering his MD fields hosted more than 350 events apiece each year while still looking great. He attributes much of his high-use suc- cess to his cultivation program. I was in the audience when Jerad spoke at a recent conference in Indiana. He mentioned that he typically accomplished some sort of aeration on his cool-season grass fields weekly. Some of these aera- tions are without soil removal during in-season, but he tries to remove cores on the majority of the cultivation trips across his field. Sports Field Manager Allen Reed at FC Dallas Stadium also is a big pro- ponent of weekly aerification. He has a bermudagrass-based field that also hosts numerous events through the year. I know these two examples are a bit extreme but they prove the point that most should aerify the fields much more often for opti- mum performance. Several years ago, Dr. Beth Guertal at Auburn University conducted deep-tine aeration studies on compacted native soils growing Tifway bermudagrass. Aerations were applied either once (July), twice (April and July), or four times (January, April, July, and October) a year with 0.75- inch solid tines that penetrated 8 inches on 4-inch spacing. Despite the total area impacted by those big tines going down deep, she found that the effects only lasted about 1 month on heavily trafficked turfgrass. This study proved that turf managers should aerate more than just once or twice a year. As a side benefit, the winter/spring aerification improved early spring green-up. So, this leads back to timing of aeri- fications. All the literature indicates that warm-season grass aeration should take place when the grass is actively grow- ing; for much of the US that is from May to September. It is best to not narrow it down by specific dates considering some climates may allow bermudagrass growth year-round. This timing is suggested primarily since there can be increased soil and tissue desiccation due to the aeri- fication holes. If the turfgrass is actively growing, roots will quickly begin to grow in around the hole's walls, cavitation of soil will begin to fill the void, and lateral stems will cover the surface. The plant will get maximum benefit from the aeration hole during this time. If the turfgrass is not actively growing, either from dormancy or due to a stress such as drought, the turf will not see the same benefit since respiration may be so low. The aerification holes can also increase the stress due to the desiccation with more tissue dieback. In addition, research suggests that the soil may even become re-compacted before the turfgrass resumes active growth. Open aerification holes in the spring may promote more soil warming since air is more easily heated than soil. This can be good or bad. If there is early green up and a late freeze, then it can increase freeze damage since it results in a more rapid drop in the soil profile's temperature and the greater chance of turf desiccation. Dr. Guertal's research work suggests it can be a positive if earlier greening is not subject to freezing injury and no one minds the open holes for the time being. Considering your situation, if you have few worries about late spring freezes and your labor situation allows you to easily get an extra aerification in for the year, then my practical side would say "start punching holes." The academic side of me would tell you to wait and try to get an extra aeration in during the growing season for optimum benefit. The final decision is yours. ■ ST PUNCHING HOLES Q&A with Dr. Grady Miller Questions? Send them to Grady Miller at North Carolina State University, Box 7620, Raleigh, NC 27695-7620, or email grady_miller@ncsu.edu Or, send your question to Pamela Sherratt at 202 Kottman Hall, 2001 Coffey Road, Columbus, OH 43210 or sherratt.1@osu.edu Professor, North Carolina State University I know these two exam- ples are a bit extreme but they prove the point that most should aerify the fields much more often for optimum performance.