Research at the University of Minnesota continues to answer critical questions asked by golf course managers across the state. Since 2013, the Member-Driven Research Initiative has investigated numerous practices, such as precise applications for plant growth regulators, ways to minimize winter injury and wetting agent impacts on surface characteristics. These studies have increased our knowledge of fine turf management on golf courses.
The leadership of the MGCSA and Executive Director, Jack MacKenzie, have developed a successful outreach program in five regions of the state and western Wisconsin. These outreach events are important for educating the MGCSA membership on the Member-Driven Research projects as well as environmental issues on the horizon.
To develop this research, the MGCSA membership is surveyed every two years to determine topics that have the most interest or value. Our last survey went out to the membership in the spring of 2015 and identified research areas of wetting agents, winter injury and water conservation; these have been our main areas of research for the past two years. The MGCSA membership will be surveyed again in January of 2017.
Wetting agent research
Our research on wetting agents has led to new information regarding the impacts of wetting agent applications to putting green surface characteristics. In 2014 and 2015, we studied the impact of monthly wetting agent programs on putting green surface firmness, bentgrass quality, volumetric moisture content and winter survivability. You can read about this work in back issues of Hole Notes magazine (April 2016, April 2015, May 2014). Additionally, a comprehensive review of wetting agent research is provided in the July, 2013 issue of Hole Notes.
A trending strategy for wetting agent applications has been to make a final application in mid to late October with the goal of improving soil moisture dynamics over the winter and into the following spring. For this, mid-October applications were made in the fall of 2014 and 2015. Wetting agent persistence was assessed in late-March of the following spring through water drop penetration tests. We found persistence into the spring from wetting agents applied in mid-October of both years, over five months later, and it was product dependent.
Based on the results from these degradation studies, we have started to investigate the breakdown of various wetting agent chemistries based on soil temperature over time. This research began in the summer of 2016, with a treatment list covering the major wetting agent categories. All wetting agents were applied at a rate of 6oz/1000ft2. Applications were made in mid-July to both native soil and sand based creeping bentgrass putting greens and irrigated immediately with 0.35 inches. Immediately following the irrigation, 2 inch diameter cores were pulled and transferred to a controlled environment set to average temperatures for this time period. As average temperatures cooled, so did the growth chamber. The growth chamber component was used to validate the results witnessed in the field. Cores were pulled from the field and from the growth chamber at 10-day intervals to measure the presence of surfactant. The same treatments were applied in early-October to native and sand-based bentgrass grown on the same research greens, but on a different trial area. While there wasn’t a growth chamber component for the October applications, soil cores were pulled from the field every 10 days. Additionally, surfactant presence will be assessed in the spring through core sampling in March and April. We anticipate the preliminary results of this work to be available to MGCSA members at the 2017 Northern Green and during 2017 outreach events.
Winterization and recovery research
We are currently conducting the second round of trials on the freezing tolerance of creeping bentgrass and bentgrass germination under cool temperatures. In round one of this freezing trial, we cloned out 10 specific genotypes each of Penncross, T-‘1, L-93, 007, and Penn A-4. We witnessed an approximate 1°C difference in LT50 (low temperature where 50% of the plants die) between the top and bottom varieties (Table 3). Although this difference is small, it was significantly different and should be considered when comparing these five varieties. The second replication of this trial is currently being grown in the greenhouse and freezing trials will be conducted in December and January.
A second study on cold tolerance is evaluating bentgrass variety germination in cold temperatures. The first round of this study was completed in the fall of 2015 and it was repeated in the spring of 2016. For this, we chose 22 varieties and germinated them in a growth chamber under simulated spring time temperatures. In replication 1, the average temperatures were 40, 50 and 60⁰F which represents the historical average temperature on April 1st, April 24th and May 17th respectively. At 40⁰F, first germination was not seen until 21 days after seeding. However, little happened after that with only 0.4% of the 8,800 seeds germinating at 31 days after seeding. In replication 2, we increased the minimum temperature to an average of 45 degrees.
Replication 2 results confirmed the results from the first run of this trial. At the 45°F average temperature, several varieties—Proclamation, Pure Select, Declaration—produced over 40% germination by day 14 (Figure 1). At this same time, several others—Independence, Penn A4, Memorial—achieved less than 15% germination. At the 50°F average temperature, Penn A4 did not reach 50% by day 14, while many others germinated to 95% (Figure 2). A similar reduced germination was recorded for Penn A4 at the 60°F temperature average(Figure 3). We have also analyzed the 7-day germination of each variety at each temperature and the cumulative total germination.
Water conservation
Water management is considered one of the most important day to day practices on a golf course and for good reason. Firm and fast is the name of the game today for playability, and from an agronomic standpoint moisture has a direct impact on turf health and rooting. In recent years we have witnessed a steady increase in the number of golf courses that are purchasing and using soil moisture meters to aid in managing water.
In the spring of 2016, we conducted a survey of MGCSA members asking questions related to moisture meter use and the results are fairly interesting. Almost 60% of the respondents (n=54) indicated that they use a soil moisture meter in some capacity. Spectrum Technologies TDR 300 is the meter in use by most, but multiple respondents indicated using the POGO meter by Stevens Water. No other meter brands were mentioned by the 31 respondents who used meters. From the survey, the main reasons for using moisture meters include to improve the precision of hand watering and to schedule nightly irrigation .
Moisture meters come in all shapes and sizes, and they have various features from wifi technology and cloud based software, to smart phone mapping systems. With all of the different features, the world of moisture meters can get confusing really quickly. We were curious to know what features are most important to you as a manager of turf. Based on your responses, quick measurement was the most important feature, followed by affordability. Surprisingly, mapping software ranked lowest in importance and this is likely a reflection of the fact that most use these tools for hand watering and nightly scheduling.
We are currently evaluating several moisture meters and they are outlined in the September, 2016 issue of Hole Notes. Our outreach program this fall is educating MGCSA members how to utilize these tools and the various features of each.
The full report is available under the Resources Tab
