THE RESEARCH PLAYBOOK
Wendell Hutchens , Ph . D .
“ Those are three primary management practices for turfgrass , but particularly with winterkill , they play a major role ,” he said . “ We found some pretty interesting data during the first couple of years of our study .”
Roberts noted that , historically , avoiding late-summer applications of nitrogen on bermudagrass was the standard . “ Healthy roots are vital to winter survival , and it was thought that fall fertilization could favor lush foliar growth in lieu of root growth , therefore increasing chances of winter injury ,” said Roberts . “ However , our research showed that slow-release nitrogen applications through mid-September had either no impact or , in some cases , positive impacts on turfgrass quality and color .
“ More importantly , no negative impacts were observed as a result of late-season nitrogen applications ,” he added .
According to Hutchens , the work with mowing height also yielded an interesting insight .
“ Mowing height didn ’ t have a substantial effect on winterkill , but it did reduce winter weed populations when we mowed at higher heights , which is a really
Joseph Roberts , Ph . D . useful finding and a serendipitous takeaway from the study ,” he said .
“ The general rule of thumb is to increase mowing heights slightly as bermudagrass approaches winter dormancy ,” said McCall . “ How much depends on the starting point while actively growing in-season .
“ In our study , 0.75 inches seemed to be the sweet spot , though we did not see consistent impacts of mowing height on winter injury . We did , however , notice that mowing lower at 0.5 inches opened the canopy enough for weeds to germinate much more frequently , and mowing at 1 inch sometimes slowed spring green up a little ,” he said .
McCall noted that these mowing heights are considerably lower than how a home lawn should be maintained .
SOIL MOISTURE IS CRITICAL Due to mild and wet winter conditions at the field trial locations in Maryland and Virginia , the researchers performed several experiments using freeze chambers to mimic winter weather conditions . When Hutchens started his job in Arkansas , he worked with Battaglia and DeBoer to evaluate the relationship between soil water content and level of cold-weather injury .
DeBoer , who mainly participated in the study as a Ph . D . student at the University of Arkansas before taking up his post with the LSU AgCenter , said the research found a strong association between soil moisture and winterkill symptoms .
“ There is definitely a positive correlation with increased soil moisture prior to short-term freezing events , resulting in better turf survival ,” DeBoer said .
One possible explanation according to DeBoer may be a temporary heating effect from the irrigation water sportsfieldmanagementonline . com December 2024 | SportsField Management
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