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Turfgrass Nutrition and Winterkill Research Update

Evaluating the effects of soil test philosophies recommendations on creeping bentgrass and annual bluegrass

This research is the Masters thesis of Jackie Guevara. The research evaluates two methods of soil test interpretation and fertilizer recommendations, Sufficiency Level of Available Nutrients (SLAN) and Minimum Levels for Sustainable Nutrition (MLSN). SLAN is an established method for determining fertilizer recommendations based on soil test results. MLSN is a more recent method for determining fertilizer recommendations and when compared to SLAN generally recommends lower application rates of phosphorus and potassium.

Winterkill Research Update

Soils were sampled in the spring of 2020. Mehlich 3 soil test extractant was used to determine soil nutrient levels and nutrient recommendations were made according to the formulas used by the MSU Soil and Plant Nutrient Lab for the SLAN method and MLSN nutrient recommendations were determined from published MLSN formulas. The study has three treatments: (1) phosphorus and potassium applied according to MLSN guidelines; (2) phosphorus and potassium applied according to SLAN guidelines; and (3) nitrogen only treatment with no phosphorus or potassium added. These treatments were applied to creeping bentgrass and an annual bluegrass putting green. The nitrogen source for all treatments is liquid urea. Treatments were applied on two blocks: Penn A-4 bentgrass and mix of Penncross creeping bentgrass and annual bluegrass. Half of the plots are trafficked three times a week. Data such as normalized difference vegetation index, turf color and quality are collected biweekly. Soils will be sampled in April 2021 and the third year of treatment applications will commence in May 2021.

Results after two years of treatments indicate few differences in turfgrass quality between the two soil testing theories. Research will continue for at least 1 more year.

Winterkill Sensor Research

In the autumn of 2020, the MTF Founders Society funded the purchase of six sensor packages to monitor winter conditions on golf course putting greens in Michigan. The sensor package was developed by scientists at the University of Minnesota that we’ve been working with as part of a large multi-university grant proposal to study winterkill. Many superintendents have written letters of support for this grant and several participated in monitoring winter conditions on putting greens at their golf courses this past winter. We are submitting this grant to the United States Department of

Agriculture Specialty Crops Research Initiative grant program again this spring with hopes that our 3rd time will be the charm.

The full title of our proposal is “WinterTurf: A holistic approach to understanding the mechanisms and mitigating the effects of winter stress on turfgrasses in northern climates.” The winterkill sensors we installed at 6 golf courses in Michigan last winter was part of the process of collecting preliminary data to support this grant. The sensor package included: soil temperature and moisture sensors at 3 depths, and oxygen and carbon dioxide sensors. Data collection from the sensors was powered by a solar panel and data was transmitted via real time via a cell signal.

We are still in the process of downloading all the data from this • past winter and troubleshooting issues with some of the sensor packages we installed.

The objectives of this research are:

1 Determine if the sensors reliably record and transmit data throughout the winter

2 Develop a model that could notify superintendents when conditions are likely to cause winterkill. This could be from soil gas, temperature, moisture data or perhaps a combination of all. Ultimately to develop a model we will need to monitor conditions on putting greens when winterkill occurs. This didn’t happen at our locations in Michigan last winter but sensors were also installed in Minnesota and Norway. Our hope is that with enough locations over enough years we will find conditions that cause kill.

3 Make the sensor package commercially available to superintendents.

I would like to thank the following superintendents for hosting sensor packages this past winter.

Jeff Holmes, Egypt Valley CC Doug Hoeh, Treetops Resort Scott Pulaski, Walloon Lake CC Jim Bluck, Arcadia Bluffs Ryan Moore, Forest Lake CC Eric Davey, Prestwick Village Golf Club